[advances in agronomy] volume 123 || global warming and its possible impact on agriculture in india

CHAPTER TWO

Global Warming and Its PossibleImpact on Agriculture in IndiaBhagirath Singh Chauhan*, Prabhjyot-Kaur†, Gulshan Mahajan†,Ramanjit Kaur Randhawa{, Harpreet Singh†, Manjit S. Kang}*Crop and Environmental Sciences Division, International Rice Research Institute, Los Banos, Philippines†Punjab Agricultural University, Ludhiana, Punjab, India{Indian Agricultural Research Institute, New Delhi, India}Department of Plant Pathology, Kansas State University, Manhattan, Kansas, USA

Contents

1.

AdvISShttp

Introduction

ances in Agronomy, Volume 123 # 2014 Elsevier Inc.N 0065-2113 All rights reserved.://dx.doi.org/10.1016/B978-0-12-420225-2.00002-9

66
2. Greenhouse Effect and Global Warming 67 3. Agents of Global Warming 68
3.1
Carbon dioxide 69 3.2 Methane 69 3.3 Nitrous oxide 69 3.4 Water vapor 70 3.5 Ozone (O3) 70
4.
Evidence for Climate Change and Impacts on Agriculture 70 5. Projected Climate Change in India 72 6. Impact of Global Warming on Agriculture and the Food Supply 75
6.1
Effect of elevated concentrations of CO2 on crop growth 76 6.2 Effect of ozone on plants 80 6.3 Effect of increasing temperature on crop growth 81 6.4 Interactive effects of changing climatic factors on crop production 86 6.5 Effect of climate change on the quality of produce 90 6.6 Agricultural surfaces and climate change 91 6.7 Soil erosion and soil fertility 93 6.8 Potential effects of climate change on pests 97
7.
Key Adaptation and Mitigation Strategies to Reduce the Effects of Climate Change 103 7.1 Crop-based approaches 105 7.2 Crops and cultivars that fit into new cropping systems and seasons 106 7.3 Cultivars suitable for high temperature, drought, inland salinity, and
submergence tolerance
107 7.4 Cultivars that respond to high CO2 concentration 109 7.5 Mitigation of the impact of climate change 109 7.6 Other strategies 111 7.7 Policy issues for managing climate change 112
65

http://dx.doi.org/10.1016/B978-0-12-420225-2.00002-9

66 Bhagirath Singh Chauhan et al.

8.
Conclusions 113 Acknowledgment 114 References 114
Abstract

Progress has been significant in climate science and the direct and indirect influences ofclimate on agricultural productivity. With the likely growth of the world's populationtoward 10 billion by 2050, demand for food crops will grow faster than demand forother crops. The prospective climate change is global warming (with associatedchanges in hydrologic regimes and other climatic variables) induced by the increasingconcentration of radiatively active greenhouse gases. Climate models project thatglobal surface air temperatures may increase by 4.0–5.8 �C in the next few decades.These increases in temperature will probably offset the likely benefits of increasingatmospheric concentrations of carbon dioxide on crop plants. Climate change wouldcreate new environmental conditions over space and time and in the intensity and fre-quency of weather and climate processes. Therefore, climate change has the potentialto influence the productivity of agriculture significantly. Climate variability has alsobecome a reality in India. The increase in mean temperature by 0.3–0.6 �C per decadesince the 1860s across India indicates significant warming due to climate change. Thiswarming trend is comparable to global mean increases in temperature in the past100 years. It is projected that rainfall patterns in India would change with the westernand central areas witnessing as many as 15 more dry days each year, whereas the north-ern and northwestern areas could have 5 to 10 more days of rainfall annually. Thus, dryareas are expected to get drier and wet areas wetter. It is projected that India's popu-lation could reach 1.4 billion by 2025 andmay exceed China's in the 2040s. If agriculturalproduction is adversely affected by climate change, livelihood and food security in Indiawould be at risk. Because the livelihood system in India is based on agriculture, climatechange could cause increased crop failure and more frequent incidences of pests.Therefore, future challenges will be more complex and demanding. This chapterfocuses on the variability of climate change and its probabilistic effects on agriculturalproductivity and adaptation and mitigation strategies that can help in managing theadverse effect of climate change on agricultural productivity, in particular for India.

1. INTRODUCTION

Climate is the synthesis of weather conditions in a given area, charac-

terized by long-term statistics (mean values, variances, probabilities of

extreme values, etc.) for the meteorologic elements in that area (World

Meteorological Organization, 1992). Generally, the quantities measured

are surface variables, such as temperature, precipitation, and wind. More

broadly, the “climate” is the description of the state of the climate system

67Global Warming and Its Possible Impact on Agriculture in India

(IPCC, 1995). Climate variability reflects deviations in climate statistics

across a given period (a specific month, season, or year) from the long-term

climate statistics relating to the corresponding calendar period (World

Meteorological Organization, 1992).

Climate affects human life on Earth. It regulates food production and

water resources and influences energy use, disease transmission, and other

aspects of human health and well-being (National Research Council

(United States), 2010). Earth’s atmosphere is mainly composed of nitrogen

(N) and oxygen (O2), but these gases have little or no influence on radiation

coming from the sun or that emitted by Earth’s surface. The so-called green-

house gases (GHGs), which include water vapor, carbon dioxide (CO2),

methane (CH4), nitrous oxide (N2O), and chlorofluorocarbons (CFCs),

however, absorb and reemit infrared radiation emitted by the surface of

the Earth and trap heat in the atmosphere. This amplified warming keeps

Earth’s surface warmer (about 33 �C) than it would be without the presenceof GHGs (National Research Council (United States), 2010).

Then, what is climate change? According to the World Meteorological

Organization (1992), climate change represents a significant change, that is, a

change with important economic, environmental, and social effects, in the

mean values of a meteorologic element, such as temperature and amount of

precipitation during a certain period, for which the means are computed

across a decade or longer (World Meteorological Organization, 1992). In

the IPCC usage, climate change occurs because of internal changes within

the climate system or in the interaction among its components or because of

changes in external forcing, either for natural reasons or because of human

activities (IPCC, 1995). Projections of future climate change reported by the

IPCC generally consider the influence on the climate of only anthropogenic

increases in GHGs and other human-related factors (IPCC, 1995). Agricul-

ture accounted for 10–12% of the total global anthropogenic emissions of

GHGs (IPCC, Working Group III, 2007).

2. GREENHOUSE EFFECT AND GLOBAL WARMING

According to the Free Dictionary by Farlex, greenhouse effect is the

phenomenon whereby Earth’s atmosphere traps solar radiation, caused by

the presence in the atmosphere of GHGs, which allow incoming sunlight

to pass through but absorb heat radiated back from Earth’s surface. Earth’s

atmosphere balances the absorption of solar radiation with emission of long-

wave radiation (infrared) to space. Not only does Earth’s surface primarily

Table 2.1 Relative contribution of greenhouse gases to anthropogenic greenhouseeffect in the United States (EIA, 2008)

Greenhouse gases

Carbon equivalent

Million metric tons Percentage

Energy-related carbon dioxide 5735.5 81.3

Methane 737.4 10.5

Nitrous oxide 300.3 4.3

Carbon dioxide from other sources 103.8 1.5

Hydrofluorocarbons (HFCs), perfluorocarbons

(PFCs), and sulfur hexafluoride (SF6)

175.6 2.5


absorb most of the short-wave radiation from the sun, but also it reradiates

some of this radiation as long-wave radiation. The atmosphere is more effi-

cient at absorbing long-wave radiation, which is then emitted both back to

space and downward toward the Earth. This downward emission heats Earth

further. This further warming by reradiated long-wave radiation from the

atmosphere is known as the greenhouse effect. The amount of long-wave

radiation that is absorbed and then reradiated downward is a function of

the constituents of the atmosphere. Certain gases in the atmosphere are

particularly good at absorbing long-wave radiation and are known as GHGs.

These include water vapor, CO2, CH4, N2O, and CFCs. (Table 2.1). If the

makeup of the atmosphere changes and the result is an increase in concen-

trations of GHGs, then more of the infrared radiation from Earth will be

absorbed by the atmosphere and then reradiated back to Earth. This changes

the radiative forcing of the climate system and results in increased temper-

ature of Earth’s surface, which affects crop growth and production. Global

warming results from the increase in greenhouse effect in the atmosphere. It

is a blanket of gases that wraps around the Earth and holds the heat in. CO2 is

the most common gas that causes global warming. The more the global tem-

perature increases, the more the climate changes.

3. AGENTS OF GLOBAL WARMING

Human and industrial activities are mainly responsible for the rise in

the concentration of GHGs in the atmosphere. CO2, the most abundant

GHG, is mainly increasing because of fossil fuel combustion. Similarly,


industrial processes cause CFC emissions. The increased agricultural activ-

ities and organic waste management are presumed to be contributing to the

buildup of CH4 and N2O in the atmosphere (Hundal and Abrol, 1991). The

GHGs produced by various activities are considered as the agents of climate

change; a brief description of these agents is given in the succeeding text.

3.1. Carbon dioxideThere is a large fixation of CO2 in agriculture, but its estimates are generally

not available because of the continuous consumption of its products by

human beings and other secondary consumers. In India, fixation of CO2

is assumed to be important because almost 190 million hectares of land is

being used for farming. The estimated dry matter production from agricul-

ture in India is almost 800 million t year�1 (Khan et al., 2009). This is equiv-

alent to fixation of 320 Tg of C or 1000 Tg of CO2 per annum. Only a part

of this is retained over time, while the rest is released back to the atmosphere.

3.2. MethaneThe total annual output of CH4 into the atmosphere from all sources in the

world is estimated to be 535 Tg year�1 (Khan et al., 2009). India’s total con-

tribution to global CH4 emissions from all sources is only 18.5 Tg year�1.

The increase in annual load of CH4 in the atmosphere is much less than that

of CO2, but its higher absorption accounts for a major contribution to global

warming. Agriculture, mainly continuously flooded rice (Oryza sativa L.)

fields and ruminant animals, is the major (68%) source of CH4 emissions.

Global annual CH4 emissions from rice paddies are less than 13 Tg year�1

and the contribution of Indian paddies to this is estimated to be only 4.2 Tg

year�1 (Bhattacharya and Mitra, 1998; Sinha et al., 1998). Low CH4 emis-

sions from rice fields in India are mainly because the soils of the major rice-

growing areas have very low organic carbon and are not continuously

flooded.

3.3. Nitrous oxideN2O, which is present in the atmosphere at a very low concentration

(310 ppbv), is increasing at 0.22�0.02% per year (Battle et al., 1996;

Machida et al., 1995; Mosier et al., 1998). But, in spite of its low concen-

tration and less rapid rise, N2O is becoming important because of its longer

lifetime (150 years) and greater global warming potential than CO2 (about

300 times more than CO2). Both fertilized and unfertilized soils contribute


to the release of this gas. The estimates of total N2O released from Indian

agriculture are low because of relatively low native soil fertility and lower

amounts of fertilizer used than in many developed countries (Khan

et al., 2009).

The major contributor to global warming is the energy sector (which

includes fossil fuel burning), which is responsible for 61% of the total con-

tribution toward global warming. Agriculture and its allied activities con-

tribute to 28% of global warming, followed by the industrial sector (8%),

wastes (2%), and land-use changes (1%).

3.4. Water vaporWater vapor is the most abundant and most important GHG because of its

contribution to the natural greenhouse effect (National Research Council,

United States, 2010). Its concentration in the lower atmosphere is controlled

by the rate of evaporation and precipitation. It is not considered a climate

forcing agent.

3.5. Ozone (O3)Ozone is found in its highest concentrations in the stratosphere that extends

from 15 to 50 km in height. It is produced by the dissociation of O2 by ultra-

violet light. It absorbs harmful ultraviolet radiation. However, the use of

aerosols, man-made halogenated gases, and CFCs has destroyed the ozone

layer in the stratosphere, contributing to global warming. The Montreal

Protocol, signed in 1987, has been ratified by 196 countries now. The ozone

layer has started to recover, but it may take decades for complete recovery

(Ebi et al., 2008). Near the Earth’s surface, however, ozone is regarded as a

pollutant, causing damage to plants, animals, and humans, and it is the main

component of smog (National Research Council, United States, 2010).

4. EVIDENCE FOR CLIMATE CHANGE AND IMPACTSON AGRICULTURE

During the past few decades, climate change, caused by global

warming, has received worldwide attention (Baer and Risbey, 2009).

The most significant change is the rise in the atmospheric temperature cau-

sed by increased concentrations of GHGs in the atmosphere. Between 1000

and 1750 AD, CO2, CH4, and N2O concentrations were 280�6 ppm,

700�60 ppb, and 270�10 ppb, respectively (IPCC, 2007a). More


recently, however, these values have increased to 369 ppm, 1750 ppb, and

316 ppb, respectively.

The global mean annual temperature at the end of the twentieth century

was almost 0.7 �C above that recorded at the end of the nineteenth century

and it is likely to increase further by 1.8–6.4 �C by AD 2100, with a best

estimate of 1.8–4.0 �C (IPCC, 2001, 2007a,b). The decade 1990–2000

was the warmest in the last 300 years and was 0.5 �C warmer than the mean

temperature of 1961–1990. Warmer summers have included record hot

spells and high sunshine hours, and the warm winters have reduced the

number of frosts. The quantity of rainfall and its distribution are also greatly

affected by climate change and these are expected to increase the problems of

flooding and soil erosion.Moreover, the sea level has risen and snow cover is

also gradually decreasing due to glacier meltdown, especially near the poles,

and arable land is decreasing near coastal regions due to inundation.

The Panel on Advancing the Science of Climate Change, set up by the

National Research Council (United States) (2010), arrived at several conclu-

sions, whose important ones were (1) that several different research groups

had shown that the planet’s mean temperature was 0.8 �C higher during the

first decade of the twenty-first century than during the first decade of the

twentieth century; (2) that much of the warming during the past several

decades could be attributed to anthropogenic activities that released into

the atmosphere CO2 and other GHGs that trap heat and burning of fossil

fuels (coal, oil, and natural gas) for energy was the largest contributor to cli-

mate change; and (3) that agriculture, forest clearing, and certain industrial

activities also made significant contributions to climate change.

The United Nations Environment Programme (UNEP) and the WMO

established the IPCC in 1988 to periodically assess the state of the global

environment. A report of the IPCC during 2001 projected that the global

mean temperature above Earth’s surface would rise 1.4–5.8 �C during the

next 100 years (IPCC, 2001).

Climate change is a well-recognized, significant, man-made, global

environmental challenge and agriculture is strongly influenced by it

(Hillel and Rosenzweig, 2011; Kang and Banga, 2013). A team of experts

from the Food and Agriculture Organization (FAO) concluded that each

1 �C rise in mean temperature would cause annual wheat (Triticum

aestivum L.) yield losses in India of about 6 million tons (US$ 1.5 billion

at current prices), and, when losses of all other crops were taken into con-

sideration, farmers were projected to lose US$ 20 billion each year (FAO,

Food and Agriculture Organization, 2008; Swaminathan, 2012). Such losses


can happen as temperature can reduce crop duration; increase crop-

respiration rates; alter photosynthate movement from source to sink; affect

the survival and distribution of pest populations, thus developing a new

equilibrium between crops and pests; hasten nutrient mineralization in soils;

decrease fertilizer-use efficiencies; and increase evaporation (Kumar et al.,

2011). Indirectly, there may be considerable effects on land use that can

be attributed to snowmelt, availability of irrigation, frequency and intensity

of inter- and intraseasonal droughts and floods, and availability of energy

(Sharma and Chauhan, 2011). All of these changes can have tremendous

effects on agricultural production and hence on the food security of a region.

More flooding, droughts, and forest fires; decreases in agricultural pro-

ductivity; and the displacement of thousands of coastal residents by sea-level

rise and intense tropical cyclones are the likely consequences of climate

change in Asia. A rise in mean temperature of 2 �C above the normal could

mean that small islands, such as Tuvalu in the Pacific Ocean and Maldives,

Lakshadweep, and Andaman and Nicobar in the Indian Ocean, could be

submerged (Swaminathan, 2012).

Global warming is mainly brought about by rapid industrialization, com-

bustion of fossil fuels, increased agricultural operations, deforestation, and the

increased number of vehicles (National Research Council, United States,

2010). The driving force behind these factors is the ever-increasing human

population. The global share of various countries in CO2 emissions is given

in Table 2.2 (Sathaye et al., 2006), and per capita emissions of C by residents

of various countries are shown in Table 2.3 (Sathaye et al., 2006). The United

States is the major contributor to CO2 emission; the US share was about one-

fourth of the total global emissions, whereas India’s contributionwas about 4%

(Table 2.2). Per capita production of C was also highest in the United States

(5.4 t ofC per person), followed byCanada (5.2 t of C per person) (Table 2.3).

India’s per capita C emissions were only 0.26 t of C per person.

5. PROJECTED CLIMATE CHANGE IN INDIA

Analysis of a representative rainfall series across the past 176 years for

India as a whole did not suggest any significant trend in rainfall change

(Sontakke, 1990). However, Rao (2007) analyzed the rainfall data of

1140 meteorologic stations in India, which showed a negative trend in rain-

fall among the stations situated in the southern states of India, southern pen-

insular areas, central India, and parts of the north and northeastern regions.

Positive trends in rainfall were observed for Gujarat, Maharashtra, coastal

Table 2.2 Global share of some countries in CO2 emissions (Sathaye et al., 2006)

Country

CO2 emissions (%)

1990 2003

Canada 2.19 2.39

China 10.41 14.07

France 1.80 1.63

Germany 4.24 3.35

India 2.63 4.07

Italy 1.91 1.85

Japan 5.54 4.79

Russia 9.67 6.38

United Kingdom 2.76 2.24

United States 23.04 23.06

Rest of the world 38.61 36.17

Table 2.3 Per capita carbon emissions from energy for the year 2003(Sathaye et al., 2006)Country Carbon emissions (t person�1)

Canada 5.19

China 0.78

France 1.86

Germany 2.78

India 0.26

Italy 2.21

Japan 2.58

Russia 3.06

United Kingdom 2.60

United States 5.44



Andhra Pradesh, and Odisha. However, the parts of the country covering

eastern Uttar Pradesh, eastern Madhya Pradesh, the west coast, and greater

parts of northwest India did not show any changes. Among the rainfed dis-

tricts, 40% of the stations showed a negative trend, 48% showed a positive

trend, and 12% showed no changes in rainfall.

Based on observations from 73 stations, an analysis of the mean annual

surface air temperature across India for 1901–1988 showed a significant

warming of about 0.4 �C per 100 years (Hingane et al., 1985). This warming

trend was comparable to the global mean temperature change of 0.5 �C in

the last 100 years. Later on, using the all-India mean surface air temperature

for 1901–2000 from a network of 31 well-distributed, representative sta-

tions, the trends in mean annual temperatures across the country were deter-

mined (Rupa Kumar et al., 2002). Warming trends were observed during

four seasons (winter, premonsoon, monsoon, and postmonsoon) with a

higher rate of temperature increase during winter (0.04 �C per decade)

and postmonsoon seasons (0.05 �C per decade) compared with the

premonsoon (0.02 �C per decade) and monsoon seasons (0.01 �C per

decade). The warming across the Indian subcontinent was mainly contrib-

uted by the postmonsoon and winter seasons. The monsoon temperatures

did not show a significant trend in most parts of India, except for a significant

negative trend across northwest India (De and Mukhopadhyay, 1998). The

diurnal temperature range has also decreased, with nighttime temperature

increasing at twice the rate of the daytime maximum temperature (Sen

Roy and Balling, 2005).

In a regional study in Punjab, Prabhjyot-Kaur and Hundal (2010)

reported gradual increases in minimum temperature across a recent

30-year period. The maximum temperature, however, showed no signifi-

cant trend at most locations in the state. A 5-year mean of annual rainfall-

variability analysis in Punjab revealed that rainfall decreased significantly

during the past five decades at the rate of 5.5, 3.4, 7.1, 4.3, and 5.5 mm

year�1 at Amritsar, Gurdaspur, Ferozepur, Bathinda, and Sangrur, respec-

tively, and rainfall increased significantly at 1.4 mm year�1 during the past

108 years at Ludhiana (Prabhjyot-Kaur et al., 2011). However, no significant

trend in rainfall variability was observed in Kapurthala, Jalandhar,

Hoshiarpur, Rupnagar, Patiala, and Faridkot districts. The IPCC compiled

data on the magnitude of change in temperature, rainfall, and CO2 for dif-

ferent parts of the world, according to which CO2 was expected to increase

to 397–416 ppm by 2050 and to 605–755 ppm by 2070 (Watson et al.,

1998). By the end of the twenty-first century, there could be a change in

Table 2.4 Changes in temperature and rainfall projected for India (Lal et al., 2001)

Year Season

Temperature change (�C) Rainfall change (%)

Lowest Highest Lowest Highest

2020 Annual 1.00 1.41 2.16 5.97

Rabi 1.08 1.54 �1.95 4.36

Kharif 0.87 1.17 1.81 5.10

2050 Annual 2.23 2.87 5.36 9.34

Rabi 2.54 3.18 �9.22 3.82

Kharif 1.81 2.37 7.18 10.52

2080 Annual 3.53 5.55 7.48 9.90

Rabi 4.14 6.31 �24.83 �4.50

Kharif 2.91 4.62 10.10 15.18


precipitation of 5–25% across India, with more reductions in winter than

summer rainfall (Prabhakar and Shaw, 2008).

There is considerable uncertainty in the magnitude of change in rainfall

and temperature predicted for India. The relative increase in temperature has

been projected to be less in kharif than in the rabi season; rabi rainfall would

have a large uncertainty, but kharif rainfall is likely to increase by as much as

10% (Lal et al., 2001) (Table 2.4). Because of the large spatial and temporal

variability in weather factors in a region, the availability of more detailed

scenarios for different agroclimatic zones is desirable. There is also increasing

consensus that climatic variability will increase in the future, leading to more

frequent extremes of weather in the form of erratic monsoons and increased

frequency and intensity of drought and flooding.

6. IMPACT OF GLOBAL WARMING ON AGRICULTUREAND THE FOOD SUPPLY

Agriculture is both a victim and an abettor of climate change (Kang

and Banga, 2013). Climate change plays a significant role in a nation’s food

security and economy, especially in a developing country such as India. For

example, Killman (2008) wrote (p. iii), “Climate change will affect all four

dimensions of food security: food availability, food accessibility, food utili-

zation and food systems stability. It will have an impact on human health,

livelihood assets, food production and distribution channels, as well as


changing purchasing power andmarket flows.” All agricultural commodities

are sensitive to climate change or climate variability (Kumar et al., 2011).

The rising temperature and CO2 and uncertainties in rainfall associated

with global climate change have serious direct and indirect consequences for

crop production and food security (Sinha and Swaminathan, 1991). It is

therefore important to evaluate the direct and indirect consequences of

global warming on different crops contributing to food security. Future agri-

cultural strategies thus have to formulate a holistic approach in the coming

decades on productivity, sustainability, profitability, stability, and equity in

Indian agriculture. Dar and Gowda (2013) suggested that improved crop,

soil, and water management practices and stress-tolerant varieties should

overcome the detrimental impacts of climate change, which in turn would

lead to improved food security, livelihoods, and environmental security.

They further pointed out that negative effects of climate change on food

security can be counteracted by broad-based economic growth, particularly

improved agricultural productivity, and robust international trade in agricul-

tural products that can offset regional shortages and agricultural productivity

investments.

The effects of changes in temperature, CO2 concentrations, and precip-

itation on crop productivity have been studied broadly using crop simulation

models (Parry et al., 2004). The combined effects of climate change may

have implications for dryland and irrigated crop yields. However, the effect

on production is expected to vary by crop and location and by the magni-

tude of warming and the direction and magnitude of precipitation change

(Adams et al., 1998). Projections by the IPCC and a few other global studies

are that, unless we adapt, there is a probability of a 10–40% loss in crop pro-

duction in India by 2080–2100 as a result of global warming (IPCC, 2007a;

Parry et al., 2004; Rosenzweig and Parry, 1994) despite the beneficial aspects

of increased CO2 concentrations (Kumar et al., 2011).

6.1. Effect of elevated concentrations of CO2 on crop growthCO2 is essential for photosynthesis and hence for plant growth. An increase

in atmospheric CO2 concentration affects crop production through altering

photosynthetic and transpiration rates. It is therefore important to assess the

combined effects of elevated atmospheric CO2 concentration and climate

change on the productivity of a region’s dominant crops (Haskett et al.,

1997). The direct effects of increased concentrations of CO2 are normally

beneficial to vegetation, especially for C3 plants, as elevated concentrations


enhance assimilation rates and increase stomatal resistance, which result in a

decline in transpiration and improved water-use efficiency in crops

(Farquhar, 1997).

Several simulation studies have been carried out to predict the likely

effects of elevated CO2 on crop yield. In northwestern India, for example,

yields of rice and wheat increased by 15% and 28%, respectively, at elevated

(doubled) CO2 concentrations (Lal et al., 1998). Similarly, Hundal and

Prabhjyot-Kaur (2007) reported a gradual increase in rice and wheat grain

yield from elevated CO2. The effects of elevated CO2 on simulated grain

yield of wheat under optimal and suboptimal (stressed) moisture conditions

are presented in Table 2.5 (adapted from Pandey et al., 2007).With the grad-

ual increase in CO2 concentration from 440 to 660 ppm, yield increased

from 21% to 68% under optimal conditions, whereas, under suboptimal

conditions, similar responses were observed with slightly lower magnitudes

(19–57%). Thus, under climate change, CO2 enhancement may increase

crop productivity. Hundal and Prabhjyot-Kaur (1996) reported that, if all

other climatic variables were kept constant (normal), leaf area index

(LAI), biomass yield, and grain yield of rice increased with elevated CO2.

With an increase in CO2 from 330 to 600 ppm, an increase as high as

11% in LAI was reported, in addition to an 8% increase in biomass yield

and 9% in grain yield (Hundal and Prabhjyot-Kaur, 1996) (Table 2.6).

Rice grown under elevated CO2 had significantly more grains and grain

yield per unit land area than under ambient CO2 and open-field conditions

(De Costa et al., 2006) (Table 2.7). In the open-field treatment, rice was

grown under normal atmospheric conditions to detect whether the presence

of a chamber had any effect on the crop. The percentage of filled grains was

also significantly higher under the elevated CO2 concentration than under

Table 2.5 Change in simulated wheat yield due to varying CO2 concentration underoptimal and suboptimal (stressed) moisture conditions (Pandey et al., 2007)

CO2 concentration (ppm)

Simulated grain yield(kg ha�1)

Change (%) frombase suboptimal andoptimal yield

Suboptimal Optimal Suboptimal Optimal

330 (base value) 3112 3837 – –

440 3695 4630 19 21

550 4327 5687 39 48

660 4876 6465 57 68

Table 2.6 Effect of CO2 increase on growth and yield of rice (Hundal and Prabhjyot-Kaur, 1996)

Parameters

Deviation from normal (%)

330 ppm (normal) 400 ppm 500 ppm 600 ppm

Maximum leaf area index 5.22 þ 1.9 þ 8.5 þ 11.1

Biomass yield (kg ha�1) 12495 þ 1.1 þ 6.1 þ 7.7

Grain yield (kg ha�1) 7563 þ 1.5 þ 6.6 þ 8.7

Table 2.7 Number of grains, percent of filled grains, grain weight, grain yield, andharvest index of rice grown under elevated (570 ppm) and ambient (370 ppm) CO2 inopen-top chambers and in open-field conditions (De Costa et al., 2006)

Parameters

Treatments

Elevated CO2 Open-field Ambient CO2

Grains (no. m�2) 47007 (11) 41793 42336

Filled grains (%) 82.9 (9) 72.1 76.0

Grain weight (mg) 24.9 (2) 24.0 24.5

Grain yield (g m�2) 871 (24) 723 783

Harvest index 0.47 0.41 0.45

The values in parentheses represent percentage increase over ambient CO2 concentration.


the ambient CO2 concentration. Individual grain weight and harvest index,

however, did not differ significantly between the elevated and ambient CO2

treatments. Grain yield under elevated CO2 was 24% higher than under

ambient CO2 concentration. Panicle dry weight in the elevated CO2 treat-

ment was significantly higher than that under the ambient CO2 and open-

field treatments throughout the grain-filling period (De Costa et al., 2006)

(Table 2.8). This was attributable to the crop’s significantly higher panicle

growth rate during the early grain-filling period, that is, 54–67 days after

transplanting. The partitioning coefficient in the elevated CO2 treatment

did not exceed that of the ambient and open-field treatments during the

early and late grain-filling periods. In cotton (Gossypium spp.), an increase

in CO2 from subambient to ambient and then to elevated concentrations

resulted in a significant increase in total dry matter production by cotton

plants (Reddy et al., 2004) (Table 2.9). This response was mainly attributable

to increased boll dry weight and lint dry weight per boll.

Table 2.8 Variation of partitioning coefficient and panicle dry weight at different timesafter rice transplanting under elevated (570 ppm) and ambient (370 ppm) CO2 in open-top chambers and in open-field conditions (De Costa et al., 2006)Days after transplanting Elevated CO2 Ambient CO2 Open-field

Partitioning coefficient

54 0.14a 0.12b 0.15a

67 0.30a 0.33a 0.34a

94 0.49b 0.51a 0.47b

Panicle dry weight (g m�2)

54 165a 118b 167a

67 693a 428b 418b

94 1036a 884b 833b

Partitioning coefficient was calculated as ratio between panicle dry weight and total dry weight.For each time (days after transplanting), horizontal means with the same letters are not significantly dif-ferent at p¼0.05.

Table 2.9 Effect of different CO2 concentrations on total dry matter, boll dry weight, lintdry weight, and seed dry weight of cotton (Reddy et al., 2004)CO2

concentrationTotal dry weight(g plant�1)

Boll dryweight (g)

Lint dry weight(g boll�1)

Seed dry weight(g boll�1)

Subambient

(180 ppm)

165c 5.6b 1.8b 2.7b

Ambient

(360 ppm)

233b 5.8a 1.8ab 2.8ab

Elevated

(720 ppm)

309a 5.9a 1.8a 2.9a

Means with the same letters within the same column are not significantly different at p¼0.05.


The growth and yield response of black gram (Vigna mungo) to CO2 con-

centrations (550 and 700 ppm) was investigated and compared with ambient

CO2 concentration (365 ppm) using open-top chambers (Vanaja et al.,

2007). The growth parameters (root and shoot length, leaf area, and root

volume) were significantly greater at 700 ppm CO2 than at 550 ppm. Com-

pared to the ambient (chamber) control, the increase in total biomass at 700

and 550 ppm CO2 was 65% and 39%, respectively (Table 2.10). The

increase in seed yield at 700 ppm (129%) was attributable to an increase

Table 2.10 Yield parameters of black gram (of 10 plants) under 365, 550, and 700 ppmCO2 (Vanaja et al., 2007)

Parameters

Parameter values Increase (%)

365 ppm 550 ppm 700 ppm550 vs.365 ppm

700 vs.365 ppm

700 vs.550 ppm

Pods (#) 158 187 239 18 51 28

Pod weight (g) 35.6 66.5 78.2 87 120 18

Seed weight (g) 17.4 32.9 39.9 89 129 21

100-seed weight (g) 2.6 2.7 3.9 2 51 48

Harvest index (%) 28.5 38.7 39.5 36 38 2

Total biomass (g) 61.1 84.9 101.1 39 65 19


in the number of pods per plant and 100-seed weight, whereas the increase

in total seed yield at 550 ppm (89%) was caused by a higher number of pods

per plant and seeds per pod. The harvest index, a very important parameter

in pulses for breaking the yield barrier, increased to 36% and 38% at 550 and

700 ppm, respectively (Table 2.10).

In rice, mean biomass increment, leaf area duration, and net assimilation

rate increased with increasing CO2 concentrations (Baker et al., 1990)

(Table 2.11). In the same study, net assimilation rate decreased and leaf area

duration increased in rice with the progression of growth stages. Grain yield

increased by nearly 32%when the CO2 concentration increased from 330 to

660 mmol CO2 mol�1 air (Baker et al., 1990; Table 2.12). The number of

panicles per plant was mainly responsible for the observed differences in

grain yield among the CO2 concentrations (Table 2.12). The number of

filled grains per panicle was the most variable yield component, whereas

individual grain weight was stable across different CO2 concentrations.

Therefore, it was concluded that grain yield depended mainly on the num-

ber of panicles on rice plants.

6.2. Effect of ozone on plantsOzone is likely to have adverse effects on plant growth. Necrotrophic

pathogens can colonize plants that are weakened by O3 at an accelerated

rate, while obligate biotroph infections might be reduced (Manning, 1995).

Table 2.11 Effect of CO2 enrichment on mean biomass increment (DW), leaf areaduration (LAD), and net assimilation rate (NAR) in rice in controlled-environmentchambers (Baker et al., 1990)

CO2 concentration(ppm)

DW (g)LAD(m2 day�1)

NAR(g m�2

day�1) DW (g)LAD(m2 day�1)

NAR(g m�2 day�1)

19–44 days after sowing 44–71 days after sowing

160 1.2 0.37 4.9 1.3 1.0 1.4

250 2.1 0.50 6.0 2.2 1.2 1.8

330 2.5 0.55 6.1 2.7 1.2 2.2

500 2.5 0.51 6.5 3.9 1.2 3.2

660 3.2 0.65 6.7 2.0 1.4 1.5

900 3.9 0.76 7.1 3.8 1.6 2.4

Standard error 0.4 0.07 1.1 1.2 0.1 0.9

Table 2.12 Mean grain yield and components of yield of rice in controlled-environmentchambers (Baker et al., 1990)CO2 concentration(ppm)

Grain yield(g plant�1)

Panicles(no. plant�1)

Filled grains(no. panicle�1)

1000-grainweight (g)

160 1.4 3.6 22 17.4

250 1.3 4.6 17 18.2

330 1.9 5.4 19 17.9

500 3.0 7.3 23 18.1

660 2.8 6.0 25 18.4

900 3.3 6.4 28 18.1

Standard error 0.6 0.9 5.5 0.83


6.3. Effect of increasing temperature on crop growthIncreases in temperature increase crop-respiration rates; reduce crop dura-

tion, the number of grains formed, and crop yield; inhibit sucrose assimila-

tion in grains; affect the survival and distribution of pest populations; hasten

nutrient mineralization in soil; decrease fertilizer-use efficiency; and increase

evaporation. In a simulation study, an increase in temperature by 2 �C


brought about a 3–10% decrease in grain/seed yield of kharif crops, such as

rice, groundnut (Arachis hypogaea L.), and soybean (Glycine max L.), and a

29% decrease in grain yield of rabi crops such as wheat (Prabhjyot-Kaur

and Hundal, 2006). Pandey et al. (2007) simulated grain yield of wheat

under incremental units of maximum temperature (1–3 �C) using the

CERES-wheat model and found a gradual decrease in yield from 3546 to

2646 kg ha�1 (8% to 31% less than the base yield) under optimal moisture

conditions (Table 2.13). Similarly, under suboptimal conditions, yield

declined from 2841 to 2398 kg ha�1 (9% to 23% less than the base yield).

The reduction in wheat yield with an increase in maximum temperature

was mainly attributable to a reduction in the duration of anthesis and in grain

filling with a rise in ambient temperature, and vice versa (Aggarwal and

Kalra, 1994).

An increase in temperature from the greenhouse effect would decrease

cereal and groundnut production; however, the impact of changes in tem-

perature would vary with the type of crop and the direction of the change

occurring. For example, if all other climatic variables were kept constant, a

temperature increase of 0.5, 1.0, 2.0, and 3.0 �C compared with the nor-

mal temperature would advance the maturity of wheat by 3, 6, 12, and

17 days, respectively (Prabhjyot-Kaur and Hundal, 2010) (Table 2.14).

On the other hand, with a temperature rise of up to 1 �C above normal,

heading of rice was not affected, but a further increase in temperature to

3 �C prolonged heading and maturity by 4 and 5 days, respectively, com-

pared with the normal temperature. Flowering in soybean was delayed up

Table 2.13 Change in simulated wheat yield due to varying temperature under optimaland suboptimal moisture conditions (Pandey et al., 2007)

Change in maximum temperaturerelative to base temperature (�C)

Simulated grain yield(kg ha�1)

Change in simulatedgrain yield relative tobase yield (%)

Suboptimal Optimal Suboptimal Optimal

þ3 2398 2646 �23 �31

þ2 2668 3091 �14 �19

þ1 2841 3546 �9 �8

�1 3190 4206 3 10

�2 3358 4485 8 17

�3 3641 4817 17 26


to 4 days and its maturity was delayed by 2 days (Table 2.14). Deviation

(increase) in temperature from the normal temperature greatly influenced

flowering and maturity in gram. With an increase in temperature of 3 �Ccompared with the normal temperature, for example, flowering and matu-

rity in chickpea (Cicer arietinum L.) advanced by 23 and 24 days, respec-

tively (Table 2.14). A study analyzed the relationship between the yield

of rice and minimum temperature across the range of 22.1–23.7 �C using

a quadratic equation and reported that rice yield declined by 10%with each

1 �C rise in minimum temperature and yield declined by 15% with each

1 �C rise in mean temperature (Peng et al., 2004).

Reddy et al. (1992) reported that cotton plants grew faster at 30/22 �C(maximum/minimum temperatures) than at either higher or lower temper-

atures. However, the plants at 35/27 �C had more boll weight than those

grown at 30/22 �C and they were more advanced in fruiting-structure for-

mation (Table 2.15). The time required to produce the first square was only

2 days longer at 40/32 �C than at 30/22 �C. At 20/12 and 25/17 �C, squaresabscised at a very early stage, whereas the maximum number of squares was

Table 2.14 Effect of temperature increase on phenology of crops (Prabhjyot-Kaur andHundal, 2010)

Crop and phenological stage

Deviation from normal temperature (days)

Normala þ0.5 �C þ1.0 �C þ2.0 �C þ3.0 �C

Rice

Heading 223 0 0 þ1 þ4

Maturity 263 þ1 þ1 þ1 þ5

Wheat

Anthesis 41 �3 �6 �12 �16

Maturity 82 �3 �6 �12 �17

Soybean

Flowering 239 þ1 þ2 þ3 þ4

Maturity 294 þ1 þ1 þ2 þ2

Chickpea

Flowering 08 �4 �7 �19 �23

Maturity 99 �5 �8 �16 �24

aJulian day (calendar day).

Table 2.15 Effect of temperature on days to appearance of first flower bud (square),days to first flower, and biomass of different parts of cotton seedlings at 56 days afteremergence (Reddy et al., 1992)

Parameters

Day/night temperature (�C)

20/12 25/17 30/22 35/27 40/32

Days to first square

(day)

38 33 27 24 29

Days to first flower

(day)

a a 53 43 b

Stem biomass

(g plant�1)

3.6�0.3 18.0�1.9 33.9�3.7 31.1

�11.2

17.2�2.1

Leaf biomass

(g plant�1)

9.0�0.7 22.7�2.0 33.7�2.0 31.5�9.6 19.8�2.1

Root biomass

(g plant�1)

1.3 2.9 6.5 6.2 4.5

Boll biomass

(g plant�1)

a a 1.3�0.4 4.1�0.6 b

Square biomass

(g plant�1)

0.04�0.01 0.61�0.1 2.27�0.3 2.70�0.3 b

Total biomass

(g plant�1)

13.5�0.9 44.2�4.0 77.7�6.9 75.3

�21.7

41.5�4.2

aSquares were abscised at very early stage.bFlowers were not formed at final harvest due to slow growth.


obtained at 30/22 �C. Fruit branches were four times greater at 30/22 �Cthan at 20/12 �C, whereas maximum vegetative branches were produced

at low temperatures (20/12 �C). Bolls and squares were produced at 30/

22 �C, whereas a 10% boll and square loss was observed at 35/27 �C during

the early reproductive period.

Hundal and Prabhjyot-Kaur (2007) studied the effect of temperature on

the growth and yield of rice and wheat. An increase in temperature

decreased the growth and yield of rice and wheat, but a decrease in temper-

ature increased their growth and yield. Both the decrease in yield and the

increase in yield were more for wheat than for rice. Compared with normal

conditions, a temperature increase of 1.0–2.0 �C caused a decrease of 4–9%

in the maximum LAI in rice (Fig. 2.1) and a decrease of 18–29% in wheat

(Fig. 2.2). Similarly, biomass yield decreased by 2–5% in rice (Fig. 2.1) and

Deviation in temperature from normal (°C)

Normal 1

Grain yield

Biomass yield

Max. LAI

−15

−3 −1

−10

−5

0

5

10

15

20

25

30D

evia

tio

n in

LA

I an

d y

ield

fro

m n

orm

al (

%)

3

Figure 2.1 Effect of temperature change on growth and yield of rice using CERES-wheatmodel (Hundal and Prabhjyot-Kaur, 2007).

Deviation in temperature from normal (°C)

Normal

Grain yield

Biomass yield

Max. LAI

−50

−3 −1

−40

−30

−20

−10

0

10

20

40

30

50

Dev

iati

on

in L

AI a

nd

yie

ld f

rom

no

rmal

(%

)

31

Figure 2.2 Effect of temperature change on growth and yield of wheat using CERES-wheat model (Hundal and Prabhjyot-Kaur, 2007).



by 14–23% in wheat (Fig. 2.2), and grain yield decreased by 3–10% in rice

(Fig. 2.1) and by 10–18% in wheat (Fig. 2.2). A decrease in temperature by

1.0–2.0 �C increased the simulated maximum LAI by 3–5% in rice and by

12–28% in wheat, biomass yield increased by 4–10% in rice and by 9–16% in

wheat, and grain yield increased by 8–15% in rice and by 7% in wheat vis-a-

vis the normal conditions (Figs. 2.1 and 2.2).

A simulation study was conducted using the CERES-wheat model to

assess the effect of an intraseasonal increase in temperature on the yield of

wheat sown on different dates (Prabhjyot-Kaur and Hundal, 2010). The

simulation results revealed that, in general, an increase in temperature from

February to mid-March severely affected the yield of early-, normal-, and

late-sown wheat (Table 2.16). The temperature increase mostly affected

the yield of the early (October)-sown crop beginning in the fourth week

of January to the first fortnight of March, the timely (November)-sown crop

during February and March, the late (fourth week of November)-sown

crop during March, and the very late (December)-sown crop during

March and the first week of April (Table 2.16). A maximum of about a

17% decrease in grain yield occurred in the early-sown crop if the temper-

ature increased by 6 �C in the first fortnight of February. This was mainly

because of a reduction in grain-filling period caused by an increase in

temperature.

6.4. Interactive effects of changing climatic factors on cropproduction

The ultimate productivity of crops is determined by the interactions of cul-

tivars, soil constituents, water, temperature, day length, etc. Temperature,

solar radiation, and water directly affect the physiological processes involved

in grain development and indirectly affect grain yield by influencing the

incidence of diseases and insects (Yoshida and Parao, 1976). Rice grain yield

was positively correlated with mean solar radiation and negatively correlated

with daily mean temperature during the reproductive stage (Yoshida and

Parao, 1976). Relatively low temperature and high solar radiation during

the reproductive stage had a positive effect on the number of spikelets

and hence increased grain yield. Solar radiation had a positive influence

on grain filling during the ripening period.

The simulation results indicated that warm climate with decreasing radi-

ation would affect the growth and yield of cereal crops. However, the harm-

ful effects of increasing temperature on growth and yield could be

counterbalanced to some extent by the increasing CO2 concentrations

Table 2.16 Effect of intraseasonal temperature increase (maximum andminimum) fromnormal on grain yield (% deviation from normal) of wheat sown on different dates usingthe CERES-wheat model (Prabhjyot-Kaur and Hundal, 2010)

Time period Date of sowing

Temperature increase from normal (�C)

þ1.0 þ2.0 þ3.0 þ4.0 þ5.0 þ6.0

First fortnight of

February

Early sown

(October 28)

�3.4 �3.7 �7.6 �11.5 �13.0 �17.2

Normal sown

(November 8)

þ1.7 �1.6 �1.8 �3.9 �7.7 �7.3

Normal sown

(November 15)

�0.5 �2.7 �1.5 �2.0 �1.3 �1.9

Normal sown

(November 25)

þ0.5 þ2.4 þ2.8 þ4.7 þ4.9 þ7.0

Late sown

(December 2)

þ0.7 þ0.6 þ0.6 þ3.4 þ3.6 þ3.7

Second fortnight

of February

Early sown

(October 28)

�2.4 �2.8 �5.2 �8.1 �10.9 �13.8

Normal sown

(November 8)

�0.4 �4.1 �5.1 �9.9 �14.2 �16.4

Normal sown

(November 15)

�2.0 �5.8 �6.0 �8.7 �9.7 �14.2

Normal sown

(November 25)

þ2.5 þ1.1 þ3.4 �0.6 �2.6 �3.3

Late sown

(December 2)

�0.5 �0.4 �1.7 �2.3 �3.1 �3.6

First fortnight of

March

Early sown

(October 28)

�2.3 �4.6 �6.8 �13.8 �8.2 �10.4

Normal sown

(November 8)

�2.7 �3.3 �6.0 �9.5 �9.5 �13.0

Normal sown

(November 15)

�4.8 �9.3 �10.1 �14.2 �16.0 �20.8

Normal sown

(November 25)

�0.5 �5.4 �6.7 �3.3 �16.0 �19.4

Late sown

(December 2)

�2.3 �1.6 �6.8 �7.6 �12.5 �17.7

Continued


Table 2.16 Effect of intraseasonal temperature increase (maximum andminimum) fromnormal on grain yield (% deviation from normal) of wheat sown on different dates usingthe CERES-wheat model (Prabhjyot-Kaur and Hundal, 2010)—cont'd

Time period Date of sowing

Temperature increase from normal (�C)

þ1.0 þ2.0 þ3.0 þ4.0 þ5.0 þ6.0

Second fortnight

of March

Normal sown

(November 8)

þ1.1 �1.5 �0.5 �0.1 �1.9 �1.5

Normal sown

(November 15)

�2.5 �1.6 �4.3 �6.9 �5.9 �8.1

Normal sown

(November 25)

�0.1 �4.7 �5.6 �9.2 �10.1 �11.2

Late sown

(December 2)

�5.5 �6.6 �12.3 �14.5 �19.1 �21.4


(Hundal and Prabhjyot-Kaur, 1996). A study reported that in India, the

adverse effects of a 1–2 �C rise in temperature could be absorbed with a

5–10% increase in precipitation (Abrol et al., 1991). A grain yield increase

of 20–30% might be possible on about 70% of the area in the rice–wheat

cropping system in India. In northern India, warming could offset some

losses in yield by early pod setting in winter grain legumes, such as chickpea

and lentil.

Mahi (1996) found that the maximum LAI, biomass, and grain yield of

wheat and rice declined when radiation decreased by 10% relative to normal

radiation but increased when radiation was enhanced by 10%. The simula-

tion results suggested that the growth and yield of wheat and rice would

be influenced by increasing temperature. The adverse effects generated

by a high-temperature scenario might be lessened to some extent by a

decrease in radiation amounts. In Punjab, India, there are indications that

the amount of radiation is likely to decrease. As a result, the production

of wheat and rice could be adversely affected, depending upon the degree

of change in radiation amount in the coming years. The past increase in

CO2 experienced to date and the projections of its increase in the future will

no doubt counterbalance the negative effects of a rise in temperature on crop

productivity.

Increased CO2 concentrations could result in greater growth and grain

yield of rice and compensate for the yield reductions caused by warmer tem-

peratures (Hundal and Prabhjyot-Kaur, 1996). Under all the scenarios of


increased CO2 concentrations (i.e., 400, 500, and 600 ppm), maximum

LAI, biomass, and grain yield of rice were favorably affected (Tables 2.17

and 2.18). The interactive effect of enhanced temperature and CO2 revealed

that adverse effects caused by an increase in temperature of up to 0.5 �Ccould be compensated for by concentrations of CO2 above 400 ppm

(Hundal and Prabhjyot-Kaur, 1996). A further increase in temperature of

up to 1.0 �C did not decrease maximum LAI, biomass, and grain yield when

CO2was nearly doubled (600 ppm) relative to the normal temperature. But,

in scenarios with nearly doubled CO2 concentrations of 600 ppm, temper-

ature increases of more than 1.0 �C above normal reduced the maximum

LAI, biomass, and grain yield of rice (Tables 2.17 and 2.18).

Table 2.17 Effect of CO2 and temperature on the deviation of leaf area index of rice(Hundal and Prabhjyot-Kaur, 1996)

Temperature (�C)

Deviation of leaf area index from normal (%)


Normal [5.22]a þ1.9 þ8.5 þ11.0

þ 0.5 �5.5 �1.9 þ2.5 þ6.6

þ 1.0 �9.3 �6.1 �4.0 þ1.7

þ 1.5 �9.8 �9.1 �5.7 �1.7

þ 2.0 �12.3 �11.9 �7.8 �5.5

aLeaf area index at normal CO2 concentration and temperature.

Table 2.18 Effect of CO2 and temperature on the deviation of rice biomass yield fromnormal (Hundal and Prabhjyot-Kaur, 1996)

Temperature (�C)

Deviation of rice yield from normal (%)


Normal [12495]a þ1.1 þ6.1 þ7.7

þ 0.5 �3.5 �1.4 þ2.2 þ4.5

þ 1.0 �6.0 �1.4 þ2.2 þ4.5

þ 1.5 �7.2 �6.8 �5.0 �2.0

þ 2.0 �7.3 �7.1 �4.0 �2.6

aBiomass yield (kg ha�1) at normal CO2 and temperature.


Das et al. (2007) conducted a preliminary study to test crop simulation

model ORYZA 2000. The model has been used to investigate the impact of

climate change (with changing temperature and CO2 concentrations) on

rice yields. The model predicted direct changes in yield by �10%, �46%,

and �72% for temperature changes of þ1, þ2, and þ3 �C, respectively.The data demonstrated that even with an up toþ1 �C warmer climate than

the normal, production might increase by about 10% in an atmosphere with

doubled CO2 concentration. However, a further increase in temperature

could negate the effect of increased CO2 concentration.

The results of the simulation study for the interactive effects of increasing

temperature and CO2 concentrations revealed that the adverse effects of

increased temperature on the growth and yield of rice were counterbalanced

to some extent by the favorable effect of increasing CO2 (Hundal and

Prabhjyot-Kaur, 2007) (Table 2.19). Under enhanced CO2 concentration

of 600 ppm, a temperature increase of 2 �C compared with normal reduced

maximum LAI by 5.5%, biomass by 2.6%, and grain yield by 2.8%. With a

temperature increase of 1 �C over normal, a CO2 concentration of

>500 ppm was able to nullify the negative deviations in growth and yield,

but, when the temperature increased by 2 �C, 600 ppm CO2 was needed to

nullify the adverse effect of temperature (Table 2.19).

6.5. Effect of climate change on the quality of produceAccording to the IPCC’s Third Assessment Report, the significance of the

impact of climate change on grain and forage quality emerges from new

research. In a previous study, the amylose content in rice grain (a major

determinant of cooking quality) increased under elevated CO2 (Conroy

Table 2.19 Effect of increasing temperature and CO2 on change (%) in maximum leafarea index (LAI), biomass yield, and grain yield of rice (Hundal and Prabhjyot-Kaur, 2007)

CO2 concentration(ppm)

Temperature changefrom normal (þ1 �C)

Temperature change fromnormal (þ2 �C)

LAIBiomassyield

Grainyield LAI Biomass yield Grain yield

330 �9.3 �6.0 �6.6 �12.3 �7.3 �7.5

400 �6.1 �4.0 �4.3 �11.9 �7.1 �7.2

500 �4.0 �2.9 �2.8 �7.8 �4.0 �4.4

600 þ0.8 þ0.8 þ0.5 �5.5 �2.6 �2.8


et al., 1994). In another study, cooked rice grains from plants grown in high-

CO2 environments were firmer than those from plants grown in ambient

CO2 environments; however, the concentrations of iron and zinc, which

are important for human nutrition, were lower (Seneweera and Conroy,

1997). Moreover, the protein content of the grains decreased with com-

bined increases in temperature and CO2 concentration (Ziska et al.,

1997). Studies have shown that higher CO2 concentrations led to reduced

plant uptake of nitrogen (N) and trace elements, such as zinc, resulting in

crops with lower nutritional value (Taub andWang, 2008). This would pri-

marily impact people in poorer countries, who are less able to compensate by

eating more food and have less varied diets (Kaur andRajni, 2012). Reduced

N content in plants used for grazing may also reduce animal productivity

(e.g., sheep depend on microbes in their gut to digest plants, which in turn

depend on N intake).

In a study, the protein content of soybean grain decreased with increases

in CO2 concentration; however, because of increased grain yield, the total

quantity of nutrients accumulated in grain per hectare still increased with

high CO2 concentrations (Mulchi et al., 1992). In the same study, increases

in CO2 concentrations from 360 to 510 ppm increased grain oil from 20.4 to

22.3% and decreased grain protein content. The N content of plants is likely

to decrease with elevated CO2, implying reduced protein.

At the International Rice Research Institute, rice (“IR72”) was grown

under three different CO2 concentrations (ambient, ambient þ200, and

ambient þ300 mL L�1 CO2) and two different air temperatures (ambient

and ambient þ4 �C) using open-top field chambers (Ziska et al., 1997).

Increasing both CO2 and air temperature reduced grain quality (e.g., protein

content). The combined effects of CO2 and temperature suggested that, in

warmer regions (i.e., >34 �C) where rice is grown, quantitative and qual-

itative changes in rice supply could occur if both CO2 and air temperature

continued to increase.

6.6. Agricultural surfaces and climate changeClimate change might increase the amount of arable land near the poles by

decreasing the amount of frozen land. As per IPCCAssessment Report (AR)

4 (Bindoff et al., 2007), the reduction in area in the ice sheets of Greenland

and Antarctica contributed greatly to sea-level rise from 1993 to 2004

(Table 2.20). Although the impacts of sea-level rise are local in nature,

the causes are global and can be attributed to nonlinearly coupled

Table 2.20 Observed rate of global sea-level rise and estimated contributions fromdifferent sources (Bindoff et al., 2007)

Source of sea-level rise

Rate of sea-level rise(mm per year)

1961–2003 1993–2003

Thermal expansion 0.42�0.12 1.60�0.50

Glaciers and ice caps 0.50�0.18 0.77�0.22

Greenland ice sheet 0.05�0.12 0.21�0.07

Antarctica ice sheet 0.14�0.41 0.21�0.35

Sum of individual climate contributions to sea-level rise 1.1�0.5 2.8�0.7

Observed total sea-level risea 1.8�0.5 3.1�0.7

Difference (observed minus sum of estimated climate

contributions)

0.7�0.7 0.3�1.0

aData prior to 1993 are from tide gauges and after 1993 are from satellite altimetry.


components of the Earth system. Sea levels are expected to rise by another

1 m by 2100 though this projection is disputed (Bindoff et al., 2007). The

rise in sea level may decrease agricultural land area, particularly in Southeast

Asia. With increasing sea levels, erosion, submergence of shorelines, and

salinity of the water table could affect agriculture by inundating low-lying

areas. Future climatic changes will affect water availability for agriculture.

Apart from monsoon rains, India depends on rivers that emanate from

the Himalayas for water-resource development. As a result of global

warming, the increase in temperature may increase snowmelt and conse-

quently snow cover will decrease. In the short run, snowmelt may increase

water flow in many rivers, which, in turn, may increase the frequency of

floods. In the long run, however, the receding snow line might reduce water

flow in these rivers. In climate-change scenarios, the onset of summer mon-

soon across India may become more uncertain and could be delayed. This

will influence not only rainfed crops but also water storage in irrigated areas.

CO2-induced warming is expected to raise the sea level as a result of

thermal expansion of the oceans and partial melting of glaciers and ice caps,

which, in turn, is expected to affect agriculture, mainly through the inun-

dation of low-lying farmland and increased salinity of coastal groundwater.

The IPCC estimates of sea-level rise above present levels are 9–29 cm by

2030, with a best estimate of 18 cm, and 28–96 cm by 2090, with a best esti-

mate of 58 cm (IPCC, 2007a). Preliminary surveys of the vulnerability of


land to inundation were made on the basis of existing contoured topo-

graphic maps, in conjunction with knowledge of the local “wave climate”

that varies between different coastlines (Parry and Carter, 1988). On the

basis of the extent of land liable to inundation, 27 countries were identified

as being vulnerable to sea-level rise.

The most severe effects of climate change on agriculture are likely to be

from flooding. Southeast Asia, because of the extreme vulnerability of sev-

eral large and heavily populated deltaic regions, would be most affected.

According to more than 20-year-old projections, a 1.5 m sea-level rise

would cause submergence of about 15% of all land (and about one-fifth

of all farmland) and render another 6% of the land more prone to frequent

flooding (UNEP, 1989). Altogether, 21% of agricultural production could

be lost. Estimates revealed that, in Egypt, 17% of national agricultural pro-

duction and 20% of all farmland, especially the most productive farmland,

would be lost as a result of a 1.5 m sea-level rise. Island nations, particularly

low-lying coral atolls, would suffer the most. In the Indian Ocean, 50% of

the land area of the Maldives would be submerged as a result of a 2 m rise in

sea level. In addition to direct farmland loss from flooding, agriculture would

experience increased costs from saltwater intrusion into surface water and

groundwater in coastal regions. Deeper tidal penetration would likely

increase the risk of flooding, and recharge of aquifers with seawater would

need to be prevented.

In addition, indirect impacts of flooding would relocate both farming

populations and production to other regions, which is a serious concern.

In Bangladesh, for example, as a result of the farmland loss from an estimated

1.5 m sea-level rise, about one-fifth of the nation’s population would be dis-

placed. It is important to emphasize, however, that the IPCC estimates of

sea-level rise are much lower (about 0.5 m by 2090 under the “business-

as-usual” scenario) than 1.5 m (UNEP, 1989).

6.7. Soil erosion and soil fertilityClimatic changes are expected to affect soils in many ways. Global warming

is likely to cause soil degradation, which could influence soil fertility.

Because the ratio of carbon (C) to N is a constant, doubling of C should lead

to storage of extra N in soils as nitrates, thus providing higher fertilizing ele-

ments for plants and enhancing crop yields (Blanco-Canqui and Lal, 2010).

The average need for N could decrease and provide an opportunity for

changing costly fertilization strategies. Climatic extremes (e.g., flooding)


would probably enhance the risk of erosion. The possible evolution of

organic matter in the soil is a highly contested issue. An increase in temper-

ature would increase the mineral production rate and lessen soil organic mat-

ter content (Salinger, 1989) (Table 2.20).

High temperatures could increase the rate of microbial decomposition of

organic matter, thus adversely affecting soil fertility in the long run, but

increases in root biomass resulting from higher rates of photosynthesis could

offset these effects (Buol et al., 1990). High temperatures could accelerate

the cycling of nutrients in the soil and more rapid root formation could pro-

mote more N fixation (Hillel and Rosenzweig, 1989). However, these ben-

efits could be minor compared with the adverse effects of changes in rainfall.

Increased rainfall in regions that are already moist, for example, could lead to

increased leaching of minerals, especially nitrates. In the Leningrad region of

Russia, an estimated one-third increase in rainfall would reduce soil produc-

tivity bymore than 20% (Pitovranov et al., 1988). Large increases in fertilizer

applications would be necessary to restore productivity (Pitovranov et al.,

1988). Decreased rainfall, particularly during summers, could have a dra-

matic effect on the soil through the increased frequency of dry spells, leading

to increased proneness to wind erosion. Susceptibility to wind erosion,

however, depends in part on the cohesiveness of the soil, which is affected

by precipitation effectiveness, and wind velocity.

An experiment was conducted with free-air CO2 enrichment (FACE) in

paddy fields at Wuxi, China, to study the effects of elevated CO2 on the

availability of soil N and phosphorus (P) (Ma et al., 2007). Soil-available

N decreased with elevated CO2 by 47% in low N and by 29% in normal

N status at the rice tillering stage (Table 2.21). In this study, elevated

CO2 caused a significant increase in root biomass, which led to higher

N uptake by the rice plants. The enhanced C input by FACE increased soil

microbial use of N and this could be the reason for reduced soil-available N.

The results of the study also reported decreased extractable soil-available

N due to elevated CO2 during the early period of rice growth. Therefore,

N mineralization was increased and N uptake was decreased by elevated

CO2 concentration during the later growth stages. In the same study,

P uptake in rice was significantly increased by elevated CO2 under both

lowN and normal N rates (Ma et al., 2007). Elevated CO2 caused a decrease

in soil-available P by 32% in low N and by 30% in normal N rates at the

jointing stage, but an increase of 22% and 21% at the heading stage and

an increase of 34% and 31% at the ripening stage were observed under

low N and normal N rates, respectively (Ma et al., 2007) (Table 2.22).

Table 2.21 Effects of elevated CO2 on soil-available N in 0–15 cm soil depth at four rice growth stages (Ma et al., 2007)

Fertilizer treatment CO2 level

Content of soil-available N at different growth stages after rice transplanting

—D27— —D49— —D76— —D123—

mg kg�1 IR mg kg�1 IR mg kg�1 IR mg kg�1 IR

Low N F 17.6�0.6 �47 17.9�0.8 10 10.7�2.2 0 9.8�2.3 �10

A 33.4�5.1 16.4�3.7 10.7�2.2 10.8�2.5

Normal N F 36.3�5.3 �29 16.6�2.1 �3 10.8�0.7 �6 11.5�2.8 11

A 51.0 �10.3 16.1�1.8 11.5�2.1 10.3 �2.4

Abbreviations: A, ambient CO2; F, elevated CO2 (200 m mol mol�1 higher than ambient).Increasing rate (IR)¼ (F�A)/A�100.D27, D49, D76, and D123 are the days after rice transplanting and equal to the tillering, jointing, heading, and ripening stages, respectively.

Table 2.22 Effects of elevated CO2 on soil-available P in 0–15 cm soil depth at four rice growth stages (Ma et al., 2007)

Fertilizer treatment CO2 level

Content of soil-available P at different growth stages after rice transplanting

—D27— —D49— —D76— —D123—

mg kg�1 IR mg kg�1 IR mg kg�1 IR mg kg�1 IR

Low N F 10.4�2.3 11.3 3.3�1.0 �32.0 5.1�1.0 22.4 5.3�0.9 33.8

A 9.3�1.8 4.8�0.3 4.2�0.9 4.0�1.4

Normal N F 10.2�1.3 �5.8 4.0�1.3 �29.6 5.1�1.8 20.8 5.4�1.6 30.7

A 10.9�2.3 5.7�0.8 4.3�1.8 4.1�1.0

Abbreviations: A, ambient CO2; F, elevated CO2 (200 m mol mol�1 higher than ambient).Increasing rate (IR)¼ (F�A)/A�100.D27, D49, D76, and D123 are the days after rice transplanting and equal to the tillering, jointing, heading, and ripening stages, respectively.


Elevated atmospheric CO2 enhanced soil P mineralization and availability of

soil P. This response was mainly because of higher root biomass. Elevated

CO2 was shown to increase phosphatase activity in the rhizosphere and exu-

dates at elevated CO2 increased the availability of soil P. Besides acid phos-

phatase activity, exudation of citrate was also important in releasing

inorganic P from aluminum–iron complexes in soils of highly P-limited sys-

tems (Ma et al., 2007).

6.8. Potential effects of climate change on pestsLike crop plants, weeds would undergo the same acceleration of growth

cycle and also benefit from carbonaceous fertilization. Under high temper-

ature, weeds with a C4 photosynthetic pathway have a competitive advan-

tage over C3 crop plants (Yin and Struik, 2008).Most of the weeds in rice are

of a C4 type and elevated CO2 may give a competitive advantage to rice (a

C3 crop) over C4 weeds (Fuhrer, 2003; Patterson, 1995). In crop–weed

competition studies, in which the photosynthetic pathway was the same,

weed growth was favored as CO2 increased. For example, the infestation

of Phalaris minor Retz. (C3) in wheat (C3) would worsen with an increase

in CO2 concentration (Mahajan et al., 2012). Because of CO2 enrichment,

the wheat crop could gain greater biomass than P. minor under well-irrigated

conditions. Under water stress, however, P. minor may have an advantage

over wheat at elevated CO2 concentration (Naidu and Varshney, 2011).

In a study in the United States, weedy rice (Oryza sativa L.) responded more

strongly than cultivated rice to rising CO2 concentration with greater com-

petitive ability (Ziska et al., 2010). These results suggest that weedy rice may

become a more problematic weed in the future in India.

In a study around three decades ago (Patterson and Flint, 1980), biomass

production in four plant species responded quite differently to CO2 concen-

trations (Table 2.23). In corn (Zea mays L.), 12 days after planting, plant bio-

mass was significantly greater at 600 and 1000 ppmCO2 concentrations than

at 350 ppm. Twenty-four days after planting, however, biomass did not dif-

fer significantly among the three CO2 concentrations. Forty-five days after

planting, biomass was significantly greater at 350 ppm than at 1000 ppm. In

Rottboellia cochinchinensis (Lour.)W.D. Clayton, biomass was significantly less

at 350 ppm CO2 than at 600 ppm CO2 at all three harvests. In soybean,

increasing CO2 concentration from 350 to 1000 ppm increased the biomass

of 45-day-old plants by 72%. InAbutilon theophrastiMedic., biomass was sig-

nificantly greater at 600 and 1000 ppm CO2 than at 350 ppm CO2 and this

Table 2.23 Effect of CO2 concentration on dry biomass of corn, Rottboelliacochinchinensis, soybean, and Abutilon theophrasti harvested at 12, 24, and 45 days afterplanting (Patterson and Flint, 1980)

Species Days after planting

Biomass (g plant�1)

350 ppm CO2 600 ppm CO2 1000 ppm CO2

Corn 12 0.63b 0.73a 0.76a

24 6.96a 6.24a 6.63a

45 91.29a 89.49ab 80.08b

R. cochinchinensis 12 0.08b 0.16a 0.15a

24 2.10b 3.82a 3.50a

45 39.25b 47.47a 38.62b

Soybean 12 0.34c 0.52b 0.61a

24 3.60c 4.68b 6.38a

45 50.55c 62.19b 87.09a

A. theophrasti 12 0.08c 0.27a 0.21b

24 1.94b 3.73a 3.65a

45 35.4c 47.96b 54.34a

Different letters within a row are significantly different at 0.05 level (according to Duncan’s multiplerange test).


was true at all three harvests. Such responses of biomass production to CO2

concentrations indicate that the effects of CO2 also depend on the age or

growth stage of the plant.

In another study, soybean was grown at ambient and elevated CO2 con-

centrations (þ250 mL L�1 CO2 above ambient concentration) with and

without the presence of a C3 weed (Chenopodium album L.) and a C4 weed

(Amaranthus retroflexus L.), to evaluate the impact of rising atmospheric CO2

on crop production losses caused by weeds (Ziska and Goins, 2006).

A significant reduction in soybean seed yield was observed with both weed

species relative to their weed-free control at each CO2 concentration. Inter-

ference from C. album caused a reduction in soybean seed yield relative to

the weed-free conditions; the reduction increased from 28% to 39% as CO2

concentration increased. There was a 65% increase in the mean biomass of

C. album at the enhancedCO2 concentration. Conversely, withA. retroflexus

interference, soybean seed yield losses decreased with increasing CO2 from


45% to 30%, with no change in themean biomass ofA. retroflexus. In a weed-

free environment, elevated CO2 resulted in a significant increase in vegeta-

tive biomass (33%) and seed yield (24%) for soybean compared with the

ambient CO2 concentration. Interestingly, the presence of both weeds

negated the ability of soybean to respond, vegetatively or reproductively,

to enhanced CO2 concentration. The results from this study suggested that

rising CO2 concentrations could alter current yield losses associated with

competition fromweeds and weed control would be very crucial in realizing

any potential increase in the economic yield of agronomic crops (e.g.,

soybean) as atmospheric CO2 concentration increases.

Climate changes may also necessitate the adaptation of agronomic prac-

tices, which in turn influence weed growth. Weed management operations,

for example, chemical and mechanical, could be influenced by climate

change. Because of sudden changes in climate, environmental stress on crops

would increase and as a result the crop could become more vulnerable to

attack by insects and pathogens and less competitive with weeds. Climate

change increases the importance of conservation tillage practices and the

adoption of these practices requires knowledge of local conditions and an

understanding of the overall system dynamics. For instance, zero tillage as

a component of conservation agriculture in wheat and inappropriate fertil-

izer application in dry-seeded rice can increase weed infestation, which in

turn increases herbicide-use and/or reduces fertilizer-use efficiency. Tem-

perature changes may cause an expansion of weeds, with some species mov-

ing to higher latitudes and altitudes (Mahajan et al., 2012). Irrigation water in

northwestern India is increasingly becoming scarce and many resource-

conserving technologies are recommended to conserve irrigation water:

for example, zero tillage in wheat, bed planting in rice and wheat, and

dry-seeded rice. This will have consequences for weed abundance and com-

position. Hardyweeds, such asRumex spp., may increase in wheat because of

increased adoption of zero tillage in wheat. Flooding is commonly the pri-

mary cultural means to suppress weeds in rice as water depths of a few cen-

timeters can suppress germination and emergence of a majority of weeds in

rice (Chauhan, 2012a; Chauhan and Johnson, 2008, 2009a, b, 2010). Alter-

nate wetting and drying in puddled and in dry-seeded rice-production sys-

tems may encourage weeds, such as Leptochloa chinensis (L.) Ness., Eleusine

indica (L.) Gaertn., Panicum repens L., Eclipta prostrata (L.) L., Eleocharis

spp., and Cyperus esculentus L. (Mahajan et al., 2009b). A dwindling supply

of irrigation water makes it difficult to maintain ponding in rice for effective

weed control. Under these circumstances, where farmers are not aware of


alternative weed control, yield losses are to be expected. Therefore, strate-

gies for weed management need to be changed according to the environ-

mental conditions.

The risk of herbicide application for weed control may increase as a result

of environmental change. Problems of resistant weeds, herbicide toxicity,

and poor weed control with herbicide application may increase in the near

future. Herbicide efficacy could be affected by elevated CO2, which has

been shown to increase the tolerance of weeds of herbicide (Ziska and

Teasdale, 2000). Changes in temperature and CO2 concentration may alter

transpiration, the number of leaf stomata, or leaf thickness, which, in turn,

may affect the absorption and translocation of herbicides. In C3 plants, an

increased concentration of leaf starch under elevated CO2 may reduce her-

bicide efficacy. Higher CO2 concentration may stimulate belowground

growth relative to aboveground growth and may favor rhizome and tuber

growth of perennial weeds (Ziska, 2003). Such information suggests that

the problem of perennial weeds in rice and wheat may increase in the near

future. These weeds, however, could be controlled through integrated

approaches that combine preventive, cultural, and chemical control mea-

sures. Integrated weed management strategies need to be developed that tar-

get weed invasion, recruitment, and reproduction. Such strategies may

include a combination of optimal fertilizer schedule, summer plowing, crop

rotation, land preparation, plant geometry modification, stale-seedbed tech-

nique, and the use of weed-competitive cultivars (Chauhan, 2012b;

Chauhan et al., 2006, 2012a,b). Knowledge of weed ecology and biology

could be used as a tool for effective weed management in futuristic

climate-change scenarios. Timely efforts to fill research gaps in management

and weed interactions are needed for the sustainability of the rice–wheat

cropping system in India. There are compelling reasons for expecting cli-

mate change to alter weed management; therefore, integrated novel

approaches must be developed to assist farmers in coping with the challenges

of weed control.

Global warming would increase rainfall in some areas, which would lead

to an increase in atmospheric humidity and the duration of the wet season

(Kaur and Rajni, 2012). Combined with higher temperatures, these condi-

tions could favor the development of fungal diseases. Similarly, because of

higher temperatures and humidity, incidences of insects and disease vectors

could increase.

Elad and Pertot (2013) had discussed the impacts of climate change on

plant pathogens and plant diseases. They explained that climate change


would affect the optimal conditions for infection, host specificity, andmech-

anisms of plant infection. They also pointed out that both pathogens and

host plants would be affected by the changing climate. The authors

suggested that climate-induced changes would affect the measures farmers

use to effectively control diseases and the viability of particular cropping sys-

tems in particular regions.

Sharma et al. (2007) reported that an increase in total rainfall

(69–260 mm) resulted in an epidemic of bacterial leaf blight (Table 2.24).

Plant diseases have a direct influence on crop productivity; however, limited

information is available on the impact of climate change on plant diseases

(Agrios, 2005; Elad and Pertot, 2013). The risk of yield losses from plant

diseases is likely to increase in the wake of climate change; however, such

production losses are rarely considered in climate assessments (Anderson

et al., 2004; Reilly et al., 2001). Climate change may have a direct influence

on the temporal and spatial distribution of plant diseases. Plant pathogens are

strongly affected by environment; therefore, the survival, rate of multiplica-

tion, vigor, sporulation, direction, distance of dispersal of inocula, rate of

spore germination, and penetration of pathogens can be affected in the

climate-change scenario (Kang et al., 2010). Research evidence has revealed

that elevated CO2 increased disease incidence or severity in some cases

(Eastburn et al., 2010; McElrone et al., 2005; Shin and Yun, 2010), but

decreased it in other cases (Hibberd et al., 1996; McElrone et al., 2010;

Pangga et al., 2004).

Table 2.24 Comparative performance of weather variables in the month of Augustduring some epidemic and nonepidemic years for bacterial leaf blight (BLB) of ricein Punjab, India (Sharma et al., 2007)

Weather parameters

BLB epidemic year BLB nonepidemic year

1976 1985 1991 1992 1999 1979 1988 1993 2002

Rainfall (mm) 260 245 107 251 69 50 70 65 25

Rainy days (no.) 13 10 10 12 4 5 7 3 5

Temperaturea 30 16 18 20 15 8 18 2 7

Humidityb 15 17 10 19 10 9 2 2 8

Sunshine (h) 6.6 7.0 7.6 5.9 7.9 9.7 8.3 10.7 6.3

Disease severity (%) 42 47 40 34 38 12 9 8 2

aNo. of days with temperature between 25 and 30 �C.bNumber of days with RH>80%.


The implications of climate change relative to insects, crop protection,

and food security have recently been highlighted by Sharma (2013). He

pointed out that changes in geographic range and insect abundance would

be expected to increase the extent of crop losses, which would affect crop

production and food security. Global warming is expected to affect host–

plant resistance, biopesticides, natural enemies, and the synthetic chemicals

now used for integrated pest management (Sharma, 2013). The author

argued that climate change would cause increased problems with insect-

transmitted diseases, particularly in developing countries, where the need

to increase and sustain food production is most critical.

Abiotic factors may have a direct effect on insect–pest population

dynamics. These factors may influence developmental rate, fecundity, sur-

vival, and voltinism (Bale et al., 2002). The rise in temperature associated

with global warming may decrease the survival rate of brown planthopper

and leaffolder in rice (Heong et al., 1995). The authors concluded that rising

temperature could change pest population dynamics of the rice ecosystem.

In another study, elevated CO2 (570 ppm) exhibited a positive effect on

brown planthopper multiplication and more than doubled its population

(45 hoppers hill�1) at peak incidence compared with the ambient CO2

(380 ppm) during the kharif season of 2010 (Prasannakumar et al., 2012).

Drought and rainfall play significant roles in soil insects’ abundance

(Srivastava et al., 2010; Staley et al., 2007). Global warming could alter vol-

tinism and this could be reflected in a change in geographic distribution

(Tobin et al., 2008). Elevated CO2 showed some impact on pest population

abundance by altering the nutritional value of plants and this could alter

insect abundance and increase the rate of herbivory (Dermody et al.,

2008; Rao et al., 2009). In a nutshell, climate change might alter the pop-

ulation dynamics of insects differently in different agroecosystems and

agroclimatic zones of India; therefore, more research is needed to under-

stand these issues. The effect of climate change may be more on temperate

insects; it could expand their range. Research is needed to systematically

document major and minor pests by investigating metabolic alteration in

insects in response to changing environment, developing prediction models,

and studying evolutionary changes under modified environment

(Karuppaiah and Sujayanad, 2012). In conclusion, changes in the spectrum

of weeds, diseases, insects, natural enemies, and antagonists; high risk of

invasion by exotic and migrant pathogens and insects; extension of geo-

graphic range; noxious abundance of several species at higher altitudes;

increased overwintering; changes in morphology and reproduction; altered


development; increased number of generations; loss of resistance in cultivars

containing temperature-sensitive genes; extension of the crop-development

season and its effect on pest synchrony; change in interspecific interactions at

different trophic levels; and decreased pesticide efficacy are some of the

impacts of climate change. Better understanding the direct and indirect

effects of climate change is crucial for developing pest-management

programs. The use of historical crop, climate, and pest-management data

vis-a-vis current conditions provides ample and immediate scope for under-

standing the effects of climate change and planning for adaptive, integrated

pest-management strategies. Another approach toward understanding of the

potential direct effects is to conduct studies under controlled conditions for

knowing how intrinsic population growth is related to temperature and

identifying relationships among temperature, phenology, and population

growth rates by the use of appropriate models. Assessing the changing pest

scenario, mapping regions vulnerable to pest risk, and evolving curative and

preventive pest-management strategies for climate stress should be empha-

sized among many approaches.

7. KEY ADAPTATION AND MITIGATION STRATEGIES TOREDUCE THE EFFECTS OF CLIMATE CHANGE

Climate change, involving frequent changes in temperature, precipi-

tation, and sea level and increased impact of GHGs, is bound to affect agri-

cultural production. Potential changes in temperature and precipitation may

have a strong influence on Indian agriculture. There have been trepidations

about a possible increase in the El Nino current, which is thought to be a

major factor contributing to drought in India. These climate-change issues

call for greater understanding of crop–climate interactions and for develop-

ing crop–weather models to devise efficient agricultural production strate-

gies (Lal et al., 2001).

India has hardly any scope for future horizontal expansion to meet the

increasing demand for food, fodder, fiber, fuel, and other products. Scope

exists only for vertical expansion. To overcome the problem of climate

change, agronomic management practices could play a significant role.

Agronomists will have to be in the forefront of the research agenda and must

develop cropping/farming systems and agronomic management practices

that would harmonize high production with ecological safety. They must

play a key role on a research team in formulating crop production technol-

ogy practices in the wake of climate change. Agronomists have to decide


which and howmuch each of the recommendations made by plant breeders,

soil scientists, entomologists, plant pathologists, etc., will make a technically

viable, socially acceptable, economically profitable, and environmentally

sound package for a particular crop in a cropping system. They must caution

against practices that can harm the system. Starting from the basics of the

soil–plant–water–atmospheric system to develop cultivation practices for

high productivity and fitting them into farming systems through multi-

disciplinary collaborative research, or a systems approach, is required.

Climatic variations are present throughout the world, but the impacts of

climate change are the most devastating in developing countries, such as

India, that have fewer resources than developed countries to cope with these

adverse affects. Sustainable food security is therefore difficult to achieve in

developing countries, especially in India, because of the ever-increasing

human population; higher demand for, and intensification of, resource

use; and increased per capita consumption (Rosenzweig and Parry, 1994).

With the emerging threats from climate change, there are many uncer-

tainties as agriculture is sensitive to short-term changes in weather and to

seasonal, annual, and long-term climatic variations. Variations in meteoro-

logic parameters, in combination with other parameters, such as soil char-

acteristics, cultivars, and pests, have a paramount influence on agricultural

productivity (Pathak andWassmann, 2009). The Fourth Assessment Report

(AR4) of the IPCC suggested that increasing trends of GHGs in the Earth’s

atmosphere could accelerate in the future, as a consequence of which, the

best estimates of increases in mean global surface temperature are likely to

be in the range of 1.8–4 �C (IPCC, 2007a). Globally, mean precipitation

is projected to increase with great deviances regionally (Meehl et al.,

2007). It is therefore imperative to chart adaptation and mitigation strategies

to counter the effects of climate change on agricultural commodities. Mit-

igation and adaptation are measured on temporal and spatial scales on which

they are effective. Mitigation strategies aim at reducing GHG emissions into

the atmosphere, and adaptation strategies aim at enabling the plants to per-

form optimally under adverse climatic conditions through cultural and

genetic manipulations.

The benefits of mitigation activities will be evident in several decades

because of the longer duration of GHGs in the atmosphere, whereas the

effects of adaptation measures should be seen immediately or in the near

future (Kumar and Parikh, 2001; Lal, 2011). The effects or benefits of mit-

igation strategies are both global and local, whereas the effects of adaptation

strategies are local or regional. The purpose of mitigation and adaptation


measures is to attempt a gradual reversal of the impact of climate change and

sustain development under the inescapable effects of climate change.

7.1. Crop-based approachesAdjustment in sowing dates is a simple yet powerful tool for adapting to the

effects of potential global warming. Krishnan et al. (2007) demonstrated

potential outcomes by adjusting the sowing time of rice at two sites

(Cuttack and Jorhat in India) by simulating crop growth under different

climate-change scenarios. Improved agronomic practices, such as altering

planting dates, helped in minimizing the effect of high temperature respon-

sible for yield instability in rice and wheat. Manipulation of planting dates

helped in reducing yield instability by keeping flowering from coinciding

with the hottest growing season (Mahajan et al., 2009a).

On several occasions in the last decade, South Asia witnessed adverse

effects of climatic variations, that is, terminal heat stress, on wheat produc-

tivity. For example, despite favorable weather conditions during the winter

of 2009–2010, an abrupt rise in night temperature during the grain-filling

stage in wheat adversely affected wheat productivity in the Indo-Gangetic

Plains (IGP) and other northern states of India (Gupta et al., 2010). The

results indicated that terminal heat stress on wheat in Punjab in

2009–2010 led to a mean yield penalty of 5.8% compared with the previous

year. However, yield losses reached 20% in a few districts of Punjab and

other transects of the IGP. The magnitude of losses varied depending on

planting time, cultivars, and other management practices.

Agronomic management of crops, such as method of sowing, can be an

effective adaptation strategy under the climate-change scenario. Bed plant-

ing of crops has proved successful in the wake of climate change as it results

in increased water-use efficiency, reduced waterlogging, better access

for interrow cultivation, weed control, banding of fertilizers, better stand

establishment, less crop lodging, and reduced seeding rates (Bhardwaj

et al., 2009; Chauhan et al., 2012a). In irrigated areas, zero tillage in wheat

cultivation has successfully reduced the demand for water and other

resources (e.g., diesel and herbicides) and zero-till systems are now consid-

ered a viable option to combat climate change. Intercropping is a time-tested

practice in the wake of climate change. If one crop fails because of flooding

or drought, the second crop provides minimum assured returns for liveli-

hood security (Mittal and Singh, 1989). Large numbers of recommendations

have been made for different zones on crop substitution and cultivar


replacement in the case of delayed onset of monsoon (Joshi and Kar, 2009).

In this approach, short-duration crops and cultivars replace long-duration

ones. In the case of early-season drought, possible options are replanting

with a crop and cultivar(s) suitable for late sowing and transplanting by rais-

ing seedlings or taking seedlings from other fields. For midseason drought,

viable options are forming dead furrows at convenient intervals (3–4 m) well

in advance of anticipated drought (within a month after seeding or imme-

diately after intercultivation) to minimize runoff and store rainwater and

thinning the plant population either within rows or by removing alternate

rows in a sole crop or removing more sensitive crop in intercropping and

harvesting the crop for fodder and allowing the stubbles to grow for grain

(ratooning) as in the case of sorghum and pearl millet. For late-season

drought, however, options are limited. A crop on relatively deep soil can

be removed and a short-duration rabi pulse crop can be sown on stored soil

moisture with subsequent rain. In the case of sorghum and pearl millet,

ratooning appears to be ideal even at the time of late-season drought, espe-

cially in deep black soils (Venkateswarlu and Shanker, 2009).

7.2. Crops and cultivars that fit into new cropping systemsand seasons

With climate change, the IGP could continue to be the major contributor of

food grains despite the scarcity of irrigation water, provided new cultivars

are grown with judiciously selected cultivation schedules. The area has three

cropping seasons: rabi or winter season fromOctober/November toMarch/

April, zaid or summer season from March/April to June/July, and kharif or

rainy season from July/August to October/November. Different cropping

systems could be practiced with the use of suitable cultivars for high yields

in this era of climate change, for example, dry-seeded rice/pigeon

pea/soybean/urad bean/cotton in kharif, potato/rape/mustard–wheat/

chickpea/lentil in rabi, and mung bean/soybean in zaid. For high profitabil-

ity for farmers, essential-oil crops such as menthol mint and medicinal crops

could be substitutes for mung bean/soybean/cotton in the zaid season as

suitable cultivars of these crops are already available. For strategic reasons,

a water-guzzling crop like sugarcane should continue to be grown in the

Himalayan terai/foothill region. Again, for augmenting the liquid biofuel

supply, crops such as mustard can be cultivated in irrigated areas for high

yield. In this direction, a mustard crop could be grown twice in the rabi sea-

son if suitable short-duration, early-maturing cultivars become available in

the future. The cotton crop yields lint and oil; therefore, it could be grown


on additional land during the kharif season. Potato should assume the role of a

staple food as it is a rich source of carbohydrates. India will need to produce

120 million tons of wheat, 25 million t of pulses, and 100 million t of oil

seeds (50 million t for biofuel purposes) by 2025 (Kumar, 2006). In the

climate-change scenario, the IGP should become a major supplier of these

commodities. Crop breeding programs with the objective of developing

climate-resilient (temperature- and drought-tolerant), high-yielding culti-

vars of the identified crops should be given high priority, so that the desired

kinds of cultivars become available in the wake of climate change.

A combination of conventional and molecular marker-assisted, muta-

tional, and transgenic breeding approaches will be required to develop

the desired kinds of crop cultivars. Crop-based coordinated programs

need to begin as early as possible to develop climate-resilient cultivars.

Recently, the Indian Agricultural Research Institute (IARI), New Delhi,

released an early-maturing basmati (fragrant) rice and a wheat cultivar suit-

able for late planting (Swaminathan and Kesavan, 2012). It appears that the

desired kinds of cultivars can also be selected in some of the ongoing breed-

ing programs. There will be a need for identifying areas where climate-

change conditions already exist or are mimicked (e.g., Rajasthan, Madhya

Pradesh, and Uttar Pradesh border areas in the IGP) and/or setting up suit-

able environmental chambers for the purpose of screening large segregating

populations to make selections (Rupakumar et al., 2006). Climate-change

issues need to be converted from a “problem” into an “opportunity.”

7.3. Cultivars suitable for high temperature, drought, inlandsalinity, and submergence tolerance

Cultivars that fit into an erratic rainfall season and are drought- and

submergence-tolerant, have high fertilizer- and radiation-use efficiency,

and can tolerate coastal salinity and seawater inundation are needed. Germ-

plasm of wild relatives and local land races could be used for developing

climate-resilient crop cultivars. There is a need to revisit germplasm that

has tolerance of heat and cold stresses but has not been used in the past

because of low yield potential. Breeding cultivars that are tolerant of

high-temperature stress should receive utmost importance. Recently, for

example, Tao et al. (2008) identified rice hybrid Guodao 6 as heat-tolerant.

Genetic improvement of heat-tolerant genotypes, especially in pulses, by

identifying and validating markers for high-temperature tolerance with high

yield potential is one of the key technological processes that could be a

significant approach for adapting to climate change. Inclusion of abiotic


stress-tolerant cultivars in cropping systems and the development and use of

new cultivars with increased resilience to drought and flooding and

increased resistance to heat shock is important for climate adaptation.

Improving the adoption and dissemination of short-duration crop cultivars

can enhance the ability of farmers to cope with variable climatic conditions.

One of themost predictable issues of CO2-induced global warming is the

melting of the ice caps and glaciers and the addition of excess water to the

sea, thereby leading to the submergence of coastal areas. Further, the coastal

areas of the world are most fertile and densely populated. Therefore, breed-

ing of crops and cultivars that can be grown in saline soils could be an effi-

cient adaptation strategy to offset the loss of agricultural land. Genetically

modified rice cultivars possessing genes for salinity tolerance have been bred

by transferring genes from the mangrove species Avicennia marina (Sultana

et al., 2012). Similarly, for developing drought-tolerant strains of rice and

other crops, Prosopis juliflora L. is being used as a donor of a gene for drought

tolerance (Swaminathan and Kesavan, 2012). With the change in climatic

scenario, corn could emerge as an alternative crop in the rice–wheat

cropping system, replacing rice. Temperate germplasm, being highly pro-

ductive, could be used for the introgression of desirable genes into promising

tropical/subtropical backgrounds for the development of inbreds suitable for

different agroclimatic conditions.

Using FR13A, one of the submergence-tolerant donors, improved rice

cultivars with submergence tolerance have been developed (e.g., Swarna-

Sub1 rice, the first submergence-tolerant product using marker-assisted

backcrossing to introduce a major QTL locus, SUB1). Cultivars with the

SUB1 trait tolerate complete submergence at the seedling stage

(Iftekharuddaula et al., 2011; Septiningsih et al., 2009; Xu et al., 2006);

however, they are susceptible to anaerobic germination. Introgression of

SUB1 did not improve germination percentage under flooded conditions.

In this direction, Nipponbare (a japonica cultivar), possessing characteristics

amenable to underwater seedling establishment, exhibited greater seedling

vigor under submergence because of rapid shoot elongation and was even

found to be better than the internationally recognized submergence-tolerant

cultivar FR13A (Vu et al., 2010). Commendable work is going on in this

direction at IRRI and elsewhere to face flood-like situations in the future

at the germination stage of the crop.

Drought occurrence is likely to be more pronounced in rainfed areas.

Although the occurrence of drought is not as sudden as other weather haz-

ards, its effect can be equally devastating, especially in developing nations. In


India, significant progress has been made in the genetic dissection of

flowering time, inflorescence architecture, temperature, and drought toler-

ance in certain model plant systems and in comparative genomics in crop

plants. The Central Research Institute for Dryland Agriculture (CRIDA)

in Hyderabad has developed a sorghum cultivar (transgenic), “SPV 462,”

that possesses tolerance of water deficit and salt stress. The germination

potential of these transgenic seeds was several times higher when challenged

with salt and water stresses and the plants had a robust root system (root bio-

mass and root length) (Maheswari et al., 2010). The scientific approach

toward drought mitigation involves the pinpointing of drought-prone areas

and the scientific management of such vulnerable areas with drought-

tolerant cultivars. A holistic approach toward the management of water,

land, crop, and other natural resources, coupled with drought-tolerant cul-

tivars, can go a long way toward alleviating the adverse impacts of drought

(Sharma et al., 2010).

7.4. Cultivars that respond to high CO2 concentrationAs projected by various models, the future climate will be rich in CO2 con-

centration and it is also clear that the vegetation will be positively benefited

by increased CO2 concentration (Farquhar, 1997). This beneficial effect will

be more pronounced for C3 plants, such as wheat, rice, barley, oats, peanut,

cotton, sugar beet, tobacco, spinach, soybean, and most trees. In all of these

plants, the elevated concentrations of CO2 will lead to higher assimilation

rates and an increase in stomatal resistance, resulting in a decline in transpi-

ration rate and improved water-use efficiency in crops. Hence, plant

breeders need to develop cultivars that are able to benefit from the high

CO2 fertilization effect. IRRI, in collaboration with several countries, is

working to alter the photosynthesis of rice from the C3 to C4 pathway by

introducing cloned genes from C4 species (e.g., corn and sorghum).

7.5. Mitigation of the impact of climate changeMany mitigation technologies are available that can help cope with the

challenges of climate change with desirable results. Agriculture, forestry,

and fisheries/aquaculture have great potential for mitigating GHG emis-

sions. According to the IPCC, the global technical mitigation potential

for agriculture will be between 5500 and 6000 million t CO2 equivalents

per year by 2030, 89% of which is assumed to be from sequestration of C in

the soil. Rice is a staple food for a large population in India and the crop


occupies the largest area in India. The maximum emission of CH4 is from

the rice-growing areas. CH4 emissions from rice fields can be restricted

with the adoption of improved agricultural practices. Resource-

conserving technologies, such as zero tillage in wheat and dry-seeded rice,

could play a major role in this direction. Zero-till systems have a direct

mitigation effect as they convert GHGs such as CO2 into O2 in the atmo-

sphere and C enriches soil organic matter. In dry-seeded rice, because of

minimum anaerobic conditions, improved root growth and diversity of

aerobic soil organisms may help in mitigating climate change. Research

has shown that yields similar to those in puddled-transplanted rice can

be achieved with alternate wetting and drying (Mahajan et al., 2011).

However, alternate wetting and drying may lead to emissions of N2O,

which has greater global warming potential than CH4 does. However, this

problem could be reduced by adopting integrated nutrient-management

practices, which can help in mitigating climate change. Integrated nutrient

management involves, in general, a combination of organic, inorganic, and

biofertilizers in proportions that will keep the soil capable of producing at

an accelerated rate without suffering physical, chemical, and biological

damage. The advantages of integrated nutrient management are increased

N-use efficiency and increased yield. The application of urease, hydroqui-

none, and nitrification inhibitors, dicyandiamide together with urea, is an

effective technology for reducing NO2 and CH4 emissions from rice fields.

The use of neem-coated urea is another simple and cost-effective technol-

ogy. Improved management of livestock and their diet could also assist in

the mitigation of GHGs. The use of improved food additives, substitution

of low-digestibility feeds with high-digestibility ones, concentrate feeding,

substituting fibrous concentrate with starchy concentrate, supplementa-

tion with molasses, and changing microflora of rumen could help in reduc-

ing CH4 emissions (Aggarwal, 2008). Efficiency of energy use in

agriculture could be improved by using better-designed machinery

(e.g., the Happy Seeder, a drill for dry seeding, zero-till drill, and bed

planter) that could increase fuel-use efficiency and help in the commercial-

ization of wind and solar power potential, and the use of a laser leveler

could also lead to mitigation (Chauhan et al., 2012a; Lal, 2011). Changing

land use by increasing the area under biofuel-producing crops and

agroforestry could help in mitigating GHG emissions, but this has to be

considered with the goal of increasing food production for national secu-

rity (Venkateswarlu et al., 2011).


7.6. Other strategiesMany options exist in soil-, water-, and nutrient-management technologies,

which can contribute to both adaptation and mitigation. The addition of

crop residues and manure to arable soils improves the soil water-holding

capacity (Benbi et al., 2011). Soil C sequestration is a useful strategy in

the wake of climate change. Although it has limitations in tropical areas

because of high temperature, a substantial quantity of C can be sequestered

with the adoption of improved agricultural practices. There are two types of

C sequestration, soil C sequestration and sequestration into vegetation.

Tree-based systems can sequester substantial quantities of C into biomass

in a short period of time (Lal, 2004). The total potential of soil

C sequestration in India is 39–49 Tg year�1. This amount includes the

potential of the restoration of degraded soils and ecosystems, which is esti-

mated at 7 –10 Tg C year�1. The potential of the adoption of improved

agronomic practices on agricultural soil is 6–7 Tg C year�1. In addition,

there is also the potential of soil inorganic-carbon sequestration estimated

at 21.8–25.6 Tg C year�1 (Lal, 2011). By providing shelter and shade, as

in agroforestry systems, the effects of extremely high temperatures may

decline (Cannell et al., 1996). The planting of multipurpose trees on

degraded lands helps in C sequestration. The agroforestry system protects

farmers from climatic variability and helps in reducing the atmospheric load

of GHGs. In India, much of the research done on in situ moisture conser-

vation, energy efficiency in agriculture, and the use of poor-quality water

relates to rainfed agriculture. The watershed approach may prove successful

in rainfed areas and help in both adaptation and mitigation. For example, soil

and water conservation work, farm ponds, and check dams help moderate

rainwater runoff and minimize flooding during high-intensity rainfalls. Lal

(2004) estimated that, by arresting water and wind erosion, 3–4.6 Tg year�1

of C could be sequestered. The withdrawal of groundwater from deeper

layers demands more energy and leads to GHG emissions in agriculture

(Hira, 2009). If surface storage of rainwater in dugout ponds is encouraged,

dependence on withdrawing groundwater might decrease. The conjunctive

use of surface water and groundwater is an important strategy to mitigate

climate change, especially where groundwater is not suitable for agriculture.

Innovative approaches in groundwater sharing may also contribute to an

equitable distribution of water and reduced energy use in pumping. Biochar

is another novel approach to sequester C in terrestrial ecosystems; several

associated products are in the process of being manufactured. India could


produce almost 310 million t of biochar annually, whose application might

offset about 50% of C emissions (292 Tg C year�1) from fossil fuels (Lal,

2005). The rice–wheat cropping system in the IGP of India produces sub-

stantial quantities of crop residues, and, if these residues can be pyrolyzed,

50% of the C in biomass could be returned to the soil as biochar, thereby

increasing soil fertility and crop yield by sequestering C (Lal, 2011).

In situ water harvesting can help increase the rainwater-use efficiency of

crops through water-conserving techniques such as compartment bunding,

ridges and furrows, strip cropping, mulching, and vegetative barriers to soil

moisture.

The diversification of sensitive agricultural production systems (e.g.,

rainfed agriculture) into less sensitive agricultural microenterprises (small-

scale vegetable and fruit production, livestock rearing, bee keeping, etc.)

can enhance adaptation to the short- and medium-term impacts of climate

change (Aggarwal, 2008). Diversifying income through other farming activ-

ities, such as livestock raising, tree farming, pond aquaculture, agroforestry,

and silvicultural practices, is a viable and effective approach to combating

climate change.

7.7. Policy issues for managing climate changeIn addition to the use of technological strategies in overcoming climate

change-related impacts on crop production, there must be a solid policy

structure and strong political determination on the part of governments

to effectively tackle climate change. A sound policy framework should

examine the issues of redesigning the social sector with a focus on vulnerable

areas/populations, liability during extreme weather events, the introduction

of new credit instruments with deferred repayment, and weather insurance

as a major vehicle to transfer risk. The role of community institutions and the

private sector in relation to agriculture should be a policy matter. Policy

initiatives toward access to banking; microcredit; insurance service before,

during, and after a disaster event; and access to communication and infor-

mation services are needed in the envisaged climate-change scenario. The

establishment of an early warning system for emerging climatic risks, such

as drought, flood, heat and cold waves, and pest outbreaks, is desired. In

India and globally, climate change is now on the political and public agenda.

In India, particular attention is being paid to the impact of climate change on

agriculture, because it could have serious implications for the food security

of the country. Most scientists and policymakers now acknowledge that


climate change will have far-reaching effects on livelihood and food security

unless significant steps are taken to deal with it effectively now. The key pol-

icy issues are (1) establishment of a “Green Research Fund” for strengthen-

ing research on adaptation, mitigation, and impact assessment; (2) facilitating

greater adoption of scientific and economic pricing policies for water, land,

energy, and other natural resources; (3) providing financial incentives for

improved land management; (4) ensuring food and livelihood security;

(5) establishing seed banks in highly variable and unpredictable environ-

ments, etc. In India, governments should invest more in water storage

and efficient water-use technologies. Investment should bemade in technol-

ogies that allow aquifer recharge and microirrigation to increase the efficient

use of available water. More investment should be made in funding projects

on cultivars with tolerance of adverse climate and on land-use systems to

ensure adequate food production in the face of climate change.

8. CONCLUSIONS

Climate change is a reality. Elevated CO concentration may increase
2
crop growth and yield due to increased photosynthesis, decreased photores-

piration, and decreased stomatal conductance. The increase in temperature,

however, may decrease grain yields of rice and wheat due to the shorter

duration of crop growth. The protein content of legume grains may decrease

with increased CO2 concentration. Elevated CO2 concentration may

increase the availability of soil N and P because of increased mineralization

and activity of phosphatase enzyme in the rhizosphere. C3 plants are likely to

compete even more vigorously than now against C4 crops and vice versa.

Increased temperature along with humidity may increase the occurrence

of insects and diseases. Because of the complexity of crop–environment

interactions, a multidisciplinary approach to the problem is required in

which plant breeders, crop physiologists, agrometeorologists, and agrono-

mists need to interact to find long-term solutions in sustaining agricultural

production. There is a need for strategic research to enhance the resilience of

Indian agriculture, including crops, natural resource management, horticul-

ture, livestock, and fisheries, for the development and application of

improved production and risk management technologies. In addition, there

is a need for technology demonstration of existing management practices for

enhancing the resilience of crops and livestock to climate change. Capacity

building of scientists and other stakeholders in agricultural research on climate

resilience may also help in developing solutions for climate change.


ACKNOWLEDGMENTWe would like to acknowledge the help of Bill Hardy in providing comments on the

manuscript.

REFERENCESAbrol, Y.P., Bagga, N., Chakravarty, N.V.K., Wattal, P.N., 1991. Impact of rise in tem-

perature on the productivity of wheat in India. In: Abrol, Y.P., Gnanam, A.,Govindjee, D.R. Ort, Teramura, A.H., Wattal, P.N. (Eds.), Proceedings of the Indo-US Workshop on Impact of Global Climate Change on Photosynthesis and PlantProductivity. Oxford and IBH Publishing, New Delhi, pp. 787–798.

Adams, R.M., Hurd, B.H., Lenhart, S., Leary, N., 1998. Effects of global climate change onagriculture: an interpretative review. Climate Res. 11, 19–30.

Aggarwal, P.K., 2008. Global climate change and Indian agriculture: impact, adaptation andmitigation. Indian J. Agric. Sci. 78, 911–919.

Aggarwal, P.K., Kalra, N., 1994. Analyzing the limitations set by climatic factors, genotypeand water and nitrogen availability on productivity of wheat II. Climatically potentialyields and management strategies. Field Crop. Res. 38, 93–103.

Agrios, G.N., 2005. Plant Pathology. Elsevier, San Diego, CA.Anderson, P.K., Cunningham, A.A., Patel, N.G., Morales, F.J., Epstein, P.R., Daszak, P.,

2004. Emerging infectious diseases of plants: pathogen pollution, climate change andagrotechnology drivers. Trends Ecol. Evol. 19, 535–544.

Baer, P., Risbey, J.S., 2009. Uncertainty and assessment of issues posed by urgent climatechange: an editorial comment. Clim. Change 92, 31–36.

Baker, J.T., Allen, L.H., Boote, K.J., 1990. Growth and yield responses of rice to carbondioxide concentration. J. Agric. Sci. 115, 313–320.

Bale, J., Masters, G., Hodkinson, I., Awmack, C., Jnbezemer, M., Brown, V.K.,Butterfield, J., Buse, A., Coulson, J.C., Farrar, J., Good, J.G., Harrington, R.,Hartley, S., Jones, T.H., Lindroth, L., Press, M., Mrnioudis, I., Watt, A.,Whittaker, A., 2002. Herbivory in global climate change research: direct effects of risingtemperature on insect herbivores. Glob. Chang. Biol. 8, 1–16.

Battle, M., Bender, M., Sowers, T., Tans, P.P., Butler, J.H., Elkins, J.W., Ellis, J.T.,Conway, T., Zhang, N., Lang, P., Clarke, A.D., 1996. Atmospheric gas concentrationsover the past century measured in air from firn at the south pole. Nature 383, 231–235.

Benbi, D.K., Manchanda, J.S., Gossal, S.K., Walia, S.S., Toor, A.S., Minhas, P.S., 2011. SoilHealth Issues for Sustaining Agriculture in Punjab. Directorate of Research, PunjabAgricultural University, Ludhiana, Punjab, Research Bulletin 4/2011.

Bhardwaj, V., Yadav, V., Chauhan, B.S., 2009. Effect of nitrogen application timings andvarieties on growth and yield of wheat grown on raised beds. Arch. Agron. Soil. Sci.56, 211–222.

Bhattacharya, S., Mitra, A.P., 1998. Greenhouse gas emissions in India for the base year 1990.Global Change 11, 30–39.

Bindoff, N.L., Willebrand, J., Artale, V., Cazenave, A., Gregory, J., Gulev, S., Hanawa, K.,LeQuere, C., Levitus, S., Nojiri, Y., Shum, C.K., Talley, L.D., Unikrishnan, A., 2007.The physical basis: contribution of working group I to the fourth assessment report of theIPCC. Cambridge University Press, Cambridge, UK.

Blanco-Canqui, H., Lal, R., 2010. Soil and water conservation. In: Principles of Soil Con-servation and Management. Springer, Netherlands, pp. 1–19.

Buol, S.W., Sanchez, P.A., Kimble, J.M., Weed, S.B., 1990. Predicted impact of climaticwarming on soil properties and use. Am. Soc. Agron. Spec. Pub. 53, 71–82.

http://refhub.elsevier.com/B978-0-12-420225-2.00002-9/rf0005













































Cannell, M.G.R., van Noordwijk, M., Ong, C.K., 1996. The central agroforestry hypoth-esis: the trees must acquire resources that the crop would not otherwise acquire. Agro-forestry Syst. 34, 27–31.

Ebi, K.L., Sussman, F.G., Wilbanks, T.J., 2008. Analyses of the effects of global change onhuman health and welfare and human systems. In: Gamble, J.L. (Ed.), A report by the USClimate Change Science Program and the Subcommittee on Global Change Research.U.S. Environmental Protection Agency, Washington, DC.

Chauhan, B.S., 2012a. Can knowledge in seed ecology contribute to improved weed man-agement in direct-seeded rice? Curr. Sci. 103, 486–489.

Chauhan, B.S., 2012b.Weed ecology and weedmanagement strategies for dry-seeded rice inAsia. Weed Technol. 26, 1–13.

Chauhan, B.S., Johnson, D.E., 2008. Germination ecology of Chinese sprangletop(Leptochloa chinensis) in the Philippines. Weed Sci. 56, 820–825.

Chauhan, B.S., Johnson, D.E., 2009a. Ecological studies on Cyperus difformis, C. iria andFimbristylis miliacea: three troublesome annual sedge weeds of rice. Ann. Appl. Biol.155, 103–112.

Chauhan, B.S., Johnson, D.E., 2009b. Ludwigia hyssopifolia emergence and growth as affectedby light, burial depth and water management. Crop Prot. 28, 887–890.

Chauhan, B.S., Johnson, D.E., 2010. The role of seed ecology in improving weed manage-ment strategies in the tropics. Adv. Agron. 105, 221–262.

Chauhan, B.S., Gill, G., Preston, C., 2006. Tillage system effects on weed ecology, herbicideactivity and persistence: a review. Aust. J. Exp. Agric. 46, 1557–1570.

Chauhan, B.S., Mahajan, G., Sardana, V., Timsina, J., Jat, M.L., 2012a. Productivityand sustainability of the rice-wheat cropping system in the Indo-Gangetic Plains ofthe Indian subcontinent: problems, opportunities, and strategies. Adv. Agron. 117,315–369.

Chauhan, B.S., Singh, R.G., Mahajan, G., 2012b. Ecology and management of weeds underconservation agriculture: a review. Crop Prot. 38, 57–65.

Conroy, J.P., Seneweera, S., Basra, A., Rogers, G., Nissen-Wooley, B., 1994. Influence ofrising atmospheric CO2 concentrations and temperature on growth, yield, and grainquality of cereal crops. Aust. J. Plant Physiol. 21, 741–758.

Dar, W.D., Gowda, C.L.L., 2013. Declining agricultural productivity and global food secu-rity. In: Kang, M.S., Banga, S.S. (Eds.), Combating Climate Change: An AgriculturalPerspective. CRC Press, Boca Raton, FL, pp. 1–10.

Das, L., Lohar, D., Sadhukhan, L., Khan, S.A., Saha, A., Sarkar, S., 2007. Evaluation of theperformance of ORYZA2000 and assessing the impact of climate change on rice pro-duction in Gangetic West Bengal. J. Agrometeorol. 9, 1–10.

De Costa, W.A.J.M., Weerakoon, W.M.W., Herath, H.M.L.K., Amaratunga, K.S.P.,Abeywardena, R.M.I., 2006. Physiology of yield determination of rice under elevatedcarbon dioxide at high temperatures in a subhumid tropical climate. Field Crop. Res. 96,336–347.

De, U.S., Mukhopadhyay, R.K., 1998. Severe heat wave over Indian subcontinent in 1998in a perspective of global climate. Curr. Sci. 75, 1308–1311.

Dermody, O., O’Neill, B.F., Zangrel, A.R., Berenbaum, Y.M.R., Delucia, E.H., 2008.Effects of elevated CO2 and O3 on leaf damage and insect abundance in soybean eco-system. Anthropod-Plant Interact. 2, 125–135.

Eastburn, D.M., Degennaro, M.M., Delucia, E.H., Dermody, O., McElrone, A.J., 2010.Elevated atmospheric carbon dioxide and ozone alter soybean diseases at SoyFACE.Glob. Chang. Biol. 16, 320–330.

EIA, 2008. Emissions of Greenhouse Gases in the United States 2008 (www.eia.gov/oiaf/1605/ggrpt/pdf/0573(2008).pdf ).





















































http://www.eia.gov/oiaf/1605/ggrpt/pdf/0573(2008).pdf

http://www.eia.gov/oiaf/1605/ggrpt/pdf/0573(2008).pdf


Elad, Y., Pertot, I., 2013. Climate change impacts on plant pathogens and plant disease. In:Kang, M.S., Banga, S.S. (Eds.), Combating Climate Change: An Agricultural Perspec-tive. CRC Press, Boca Raton, FL, pp. 183–211.

FAO (Food and Agriculture Organization), 2008. Climate Change and Food Security:A Framework Document. FAO of the United Nations, Rome, 107 pp.

Farquhar, G.D., 1997. Carbon dioxide and vegetation. Science 278, 1411.Fuhrer, J., 2003. Agroecosystem responses to combinations of elevated CO2, ozone, and

global climate change. Agric. Ecosyst. Environ. 97, 1–20.Gupta, R., Gopal, R., Jat, M.L., Jat, R.K., Sidhu, H.S., Minhas, P.S., Malik, R.K.,

Gupta, R., Gopal, R., Jat, M.L., Jat, R.K., Sidhu, H.S., Minhas, P.S., Malik, R.K.,2010. Wheat productivity in Indo-Gangetic plains of India during 2010: terminal heateffects and mitigation strategies. PACA Newsletter .

Haskett, J.D., Pachepsky, Y.A., Acock, B., 1997. Increase of CO2 and climate change effectson Iowa soybean yield, stimulated using GLYSIM. Agron. J. 89, 167–176.

Heong, K.L., Song, Y.H., Pimsamarn, S., Zhang, R., Bae, S.D., 1995. Global warming andrice arthropod communities. In: Peng, S., Ingram, K.T., Neue, H.U., Ziska, L.H. (Eds.),Climate Change and Rice. Springer, Berlin, pp. 327–335.

Hibberd, J.M.,Whitbread, R., Farrar, J.F., 1996. Effect of elevated concentrations of CO2 oninfection of barley by Erysiphe graminis. Physiol. Mol. Plant Pathol. 48, 37–53.

Hillel, D., Rosenzweig, C., 1989. The Greenhouse Effect and Its Implications RegardingGlobal Agriculture. Massachusetts Agricultural Experiment Station, Amherst, MA,Research Bulletin No. 724.

Hillel, D., Rosenzweig, C., 2011. Climate change and agroecosystems: key issues. In:Hillel, D., Rosenzweig, C. (Eds.), Handbook of Climate Change and Agroecosystems:Impacts, Adaptation and Mitigation. Imperial College Press, London, pp. 1–5.

Hingane, L.S., Rupa Kumar, K., Ramana Murty, B.V., 1985. Long term trends of surface airtemperature in India. J. Climatol. 5, 521–528.

Hira, G.S., 2009.Water management in northern states and the food security of India. J. CropImprov. 23, 136–157.

Hundal, S.S., Abrol, I.P., 1991. Perspectives of greenhouse gases in climatic change and plantproductivity. In: Abrol, I.P. et al., (Ed.), Indo-US Workshop on Impact of Global Cli-matic Changes on Photosynthesis and Plant Productivity, New Delhi, India,pp. 767–779.

Hundal, S.S., Prabhjyot-Kaur, 1996. Climatic change and its impacts on crop productivity inPunjab, India. In: Abrol, Y.P., Gadgil, S., Pant, G.B. (Eds.), Climatic Variability andAgriculture. Narosa Publishing House, New Delhi, India, pp. 377–393.

Hundal, S.S., Prabhjyot-Kaur, 2007. Climatic variability and its impact on cereal productiv-ity in Indian Punjab. Curr. Sci. 92, 506–512.

Iftekharuddaula, K.M., Newaz, M.A., Salam, M.A., Ahmed, H.U., Mahbub, M.A.A.,Septiningsih, E.M., Collard, B.C.Y., Sanchez, D.L., Pamplona, A.M., Mackill, D.J.,2011. Rapid and high-precision marker assisted backcrossing to introgress the SUB1QTL into BR11, the rainfed lowland rice mega variety of Bangladesh. Euphytica178, 83–97.

IPCC, 1995. Climate Change: A Glossary by the Intergovernmental Panel on ClimateChange. IPPCC, Geneva, Switzerland.

IPCC, 2001. Climate Change 2001: The Scientific Basis. Contributions of Working GroupI to the Third Assessment Report of the Intergovernmental Panel on Climate Change.Cambridge University Press, Cambridge.

IPCC, 2007a. Contribution of working groups I, II, and III to the fourth assessment report ofthe intergovernmental panel on climate change. In: Pachauri, R.K., Reisinger, A. (Eds.),Climate Change 2007: Synthesis Report. IPCC, Geneva, Switzerland.

























































IPCC, 2007b. Summary for policymakers. In: Parry, M.L., Canziani, O.F., Palutikof, J.P.,van der Linden, P.J., Hanson, C.E. (Eds.), Climate Change 2007: Impacts, Adaptationand Vulnerability. Contribution of Working Group II to the Fourth Assessment Reportof the Intergovernmental Panel on Climate Change. Cambridge University Press,Cambridge, pp. 7–22.

IPCC. Working Group III, 2007. Mitigation of climate change. In: Metz, B.,Davidson, O.R., Bosch, P.R., Dave, R., Meyer, L.A. (Eds.), 2007. Fourth AssessmentReport. Cambridge University Press, New York.

Joshi, N.L., Kar,M., 2009. Contingency crop planning for dryland areas in relation to climatechange. Indian J. Agron. 54, 237–243.

Kang, M.S., Banga, S.S., 2013. Global agriculture and climate change: a perspective. In:Kang, M.S., Banga, S.S. (Eds.), Combating Climate Change: An Agricultural Perspec-tive. CRC Press, Boca Raton, FL, pp. 11–25.

Kang, W.S., Yun, S.C., Park, E.W., 2010. Nonlinear regression analysis to determine infec-tion models of Colletotrichum acutatum causing anthracnose of chili pepper using logisticequation. Plant Pathol. J. 26, 17–24.

Karuppaiah, V., Sujayanad, G.K., 2012. Impact of climate change on population dynamics ofinsect pests. World J. Agric. Sci. 8, 240–246.

Kaur, R., Rajni, 2012. Climate change and its possible impacts on agriculture in India. IndianFarming 62, 10–15, 18.

Khan, S.A., Kumar, S., Hussain,M.Z., Kalra, N., 2009. Climate change, climate variability andIndian agriculture: impacts, vulnerability and adaptation strategies. In: Singh, S.N. (Ed.),Climate Change and Crop. Springer-Verlag, Berlin, Heidelberg, pp. 19–38.

Killman, W., 2008. Foreword. In: Climate Change and Food Security: A Framework Doc-ument. FAO of the United Nations, Rome, p. iii.

Krishnan, P., Swain, D.K., Bhaskar, B.C., Nayak, S.K., Dash, R.N., 2007. Impact of ele-vated CO2 and temperature on rice yield and methods of adaptation as evaluated by cropsimulation studies. Agr. Ecosyst. Environ. 122, 233–242.

Kumar, S., 2006. Climate change and crop breeding objectives in the twenty first century.Curr. Sci. 90, 1053–1054.

Kumar, K.S.K., Parikh, J., 2001. Indian agriculture and climate sensitivity. Glob. Environ.Chang. 11, 147–154.

Kumar, S.N., Aggarwal, P.K., Rani, S., Jain, S., Saxena, R., Chauhan, N., 2011. Impact ofclimate change on crop productivity in Western Ghats, coastal and north eastern regionsof India. Curr. Sci. 101, 332–341.

Lal, R., 2004. Soil carbon sequestration impacts on global climate change and food security.Science 304, 1623–1627.

Lal, M., 2005. Climate change—implications for India’s water resources. In: Mirza, M.M.Q.,Ahmad, Q.K., Balkema, A.A. (Eds.), Climate Change and Water Resources in SouthAsia. Taylor and Francis Group, UK, pp. 15–193.

Lal, M., 2011. Implications of climate change in sustained agricultural productivity in SouthAsia. Regional Environ. Change 11, 79–94.

Lal, M., Singh, K.K., Srinivasan, G., Rathore, L.S., Naidu, D., Tripathi, C.N., 1998.Growth and yield response of soybean in Madhya Pradesh, India to climatic variabilityand change. Agr. Forest. Meteorol. 89, 101–114.

Lal, M., Nozawa, T., Emori, S., Harasawa, H., Takahashi, K., Kimoto, M., Abe-Ouchi, A.,Nakajima, T., Numaguti, A., 2001. Future climate change: implications for Indian sum-mer monsoon and its variability. Curr. Sci. 81, 1196–1207.

Ma, H.L., Zhu, J.G., Liu, G., Xie, Z.B., Wang, Y.L., Yang, L.X., Zeng, Q., 2007. Avail-ability of soil nitrogen and phosphorous in a typical rice–wheat rotation system underelevated atmospheric CO2. Field Crop. Res. 100, 44–51.























































Machida, T., Nakazawa, T., Fujii Yaola, S., Watanabe, O., 1995. Increase in the atmosphericnitrous oxide concentration during the last 250 years. Geophys. Res. Lett. 22,2921–2924.

Mahajan, G., Bharaj, T.S., Timsina, J., 2009a. Yield and water productivity of rice as affectedby time of transplanting in Punjab, India. Agric. Water Manage. 96, 525–535.

Mahajan, G., Chauhan, B.S., Johnson, D.E., 2009b. Weed management in aerobic rice inNorthwestern Indo-Gangetic Plains. J. Crop Improv. 23, 366–382.

Mahajan, G., Timsina, J., Singh, K., 2011. Performance and water use efficiency of rice rel-ative to establishment methods in northwestern Indo-Gangetic Plains. J. Crop Improv.25, 597–617.

Mahajan, G., Singh, S., Chauhan, B.S., 2012. Impact of climate change on weeds in the rice–wheat cropping system. Curr. Sci. 102, 1254–1255.

Maheswari, M., Varalaxmi, Y., Vijayalashmi, A., Yadav, S.K., Sharmila, P.,Venkateswarlu, B., Pardha Saradhi, P., 2010. Metabolic engineering using mtlD geneenhances tolerance to water deficit and salinity in sorghum. Biol. Plant. 54, 647–652.

Mahi, G.S., 1996. Effect of Climate Change on Simulated Wheat and Rice Yield UnderPunjab Conditions. Punjab Agricultural University, Ludhiana, India.

Manning, W.J., 1995. Climate change: potential effects of increased atmospheric carbondioxide (CO2), ozone (O3), and ultraviolet-B (UV-B) radiation on plant diseases. Envi-ron. Pollut. 88, 219–245.

McElrone, A.J., Reid, C.D., Hoye, K.A., Hart, E., Jackson, R.B., 2005. Elevated CO2

reduces disease incidence and severity of a red maple fungal pathogen via changes in hostphysiology and leaf chemistry. Glob. Chang. Biol. 11, 1828–1836.

McElrone, A.J., Hamilton, J.G., Krafnick, A.J., Aldea, M., Knepp, R.G., De Lucia, E.H.,2010. Combined effects of elevated CO2 and natural climatic variation on leaf spot dis-eases of redbud and sweetgum trees. Environ. Pollut. 158, 108–114.

Meehl, G.A., Stocker, T.F., Collins, W.D., Friedlingstein, P., Gaye, A.T., Gregory, J.M.,Kitoh, A., Knutti, R., Murphy, J.M., Noda, A., Raper, S.C.B., Watterson, I.G.,Weaver, A.J., Zhao, Z.-C., 2007. Global climate projections. In: Solomon, S.,Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M.,Miller, H.L. (Eds.), Climate Change 2007: The Physical Science Basis. Contributionof Working Group I to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change. Cambridge University Press, Cambridge, UK and New York,USA, pp. 747–846.

Mittal, S.P., Singh, P., 1989. Intercropping field crops between rows of Leucaena leucocephalaunder rainfed conditions in northern India. Agroforestry Syst. 8, 165–172.

Mosier, A.R., Duxbury, J.M., Freney, J.R., Hienemeyer, O., Mnami, K., 1998. Assessingand mitigating nitrous oxide emissions from agricultural soils. Climate Change 40, 7–38.

Mulchi, C.L., Slaughter, L., Saleem,M., Lee, E.H., Pausch, R., Rowland, R., 1992. Growthand physiological characteristics of soybean in open-top chambers in response to ozoneand increased atmospheric CO2. Agric. Ecosyst. Environ. 38, 107–118.

Naidu, V.S., Varshney, J.G., 2011. Interactive effect of elevated CO2, drought and weedcompetition on carbon isotope discrimination (13C) in wheat (Triticum aestivum) leaves.Indian J. Agric. Sci. 81, 1026–1029.

National Research Council (US), 2010. Advancing the science of climate change. America’sClimate Choices: Panel on Advancing the Science of Climate Change, The NationalAcademies Press, Washington, DC.

Pandey, V., Patel, H.R., Patel, V.J., 2007. Impact assessment of climate change on wheatyield in Gujarat using CERES-wheat model. J. Agrometeorol. 9, 149–157.

Pangga, I.B., Chakraborty, S., Yates, D., 2004. Canopy size and induced resistance inStylosanthes scabra determine anthracnose severity at high CO2. Phytopathology 94,221–227.




























































Parry, M.L., Carter, T.R., 1988. The assessments of the effects of climatic variations on agri-culture: aims, methods and summary of results. In: Konijn, N.T. (Ed.), The Impact ofClimatic Variations on Agriculture, Vol. 1, Assessments in Cool Temperate and ColdRegions. Kluwer, Dordrecht, The Netherlands.

Parry, M.L., Rosenzweig, C., Iglesias, A., Livermore, M., Fischer, G., 2004. Effects of cli-mate change on global food production under SRES emissions and socio-economic sce-narios. Glob. Environ. Chang. 14, 53–67.

Pathak, H., Wassmann, R., 2009. Quantitative evaluation of climatic variability and risks forwheat yield in India. Climate Change 93, 157–175.

Patterson, D.T., 1995. Weeds in a changing climate. Weed Sci. 43, 685–701.Patterson, D.T., Flint, E.P., 1980. Potential effects of global atmospheric CO2 enrichment on

the growth and competitiveness of C3 and C4 weed and crop plants. Weed Sci. 28, 71–75.Peng, S., Huang, J., Sheehy, J.E., Laza, R.C., Visperas, R.M., Zhong, X., Centeno, G.S.,

Khush, G.S., Cassman, K.G., 2004. Rice yields decline with higher night temperaturefrom global warming. Proc. Natl. Acad. Sci. U. S. A. 101, 9971–9975.

Pitovranov, S.E., Lakimets, V., Kiselev, V.I., Sirotenko, O.D., 1988. The effects of climaticvariations on agriculture in the subarctic zone of the USSR. In: Parry, M.L.,Carter, T.R., Konijn, N.T. (Eds.), The Impact of Climatic Variations on Agriculture,Volume 1, Assessments in Cool Temperate and Cold Regions. Kluwer, Dordrecht,The Netherlands, pp. 617–722.

Prabhakar, S.V.R.K., Shaw, R., 2008. Climate change adaptation implications for droughtrisk mitigation: a perspective for India. Climate Change 88, 113–130.

Prabhjyot-Kaur, Hundal, S.S., 2006. Effect of possible futuristic climate change scenarios onproductivity of some kharif and rabi crops in the central agroclimatic zone of Punjab.J. Agric. Phys. 6, 21–27.

Prabhjyot-Kaur, Hundal, S.S., 2010. Global climate change vis-a-vis crop productivity. In:Jha, M.K., Jha, M.K. (Eds.), Natural and Anthropogenic Disasters: Vulnerability, Pre-paredness and Mitigation. Capital Publishing Company and Springer, New Delhi andThe Netherlands, pp. 413–431.

Prabhjyot-Kaur, Singh, H., Mukherjee, J., Bal, S.K., 2011. Changing rainfall scenarios inPunjab: a variability trend analysis. In: Proceedings of International Conference on “Pre-paring Agriculture for Climate Change”. PAU, Ludhiana, India, p. 411.

Prasannakumar, N.R., Chander, S., Pal, M., 2012. Assessment of impact of climate changewith reference to elevated CO2 on rice brown planthopper,Nilaparvata lugens (Stal.) andcrop yield. Curr. Sci. 103, 1201–1205.

Rao, G.G.S.N., 2007. Consolidated report (2004–07) on impact, adaptation, and vulnera-bility of Indian agriculture to climate change. Network Project on Climate Change.Indian Council of Agricultural Research, New Delhi, India.

Rao, M.S., Srinivas, K., Vanaja, M., Rao, G.G.S.N., Venkateswarlu, B., Ramakrishna, Y.S.,2009. Host plant (Ricinus communis Linn.) mediated effects of elevated CO2 on growthperformance of two insect folivores. Curr. Sci. 97, 7–10.

Reddy, K.R., Reddy, V.R., Hodges, H.F., 1992. Temperature effects on early season cottongrowth and development. Agron. J. 84, 229–237.

Reddy, K.R., Koti, S., Davidonis, G.H., Reddy, V.R., 2004. Interactive effects of carbondioxide and nitrogen nutrition on cotton growth, development, yield, and fiber quality.Agron. J. 96, 1148–1157.

Reilly, J., et al., 2001.Agriculture: the potential consequences of climate variability and changefor the United States. In: US National Assessment of the Potential Consequences of Cli-mate Variability and Change. Press Syndicate of the University of Cambridge, NewYork.

Rosenzweig, C., Parry, M.L., 1994. Potential impact of climate change on world food sup-ply. Nature 367, 133–138.





























































Rupa Kumar, K., Krishna Kumar, K., Pant, G.B., Srinivisan, G., 2002. Climate change: theIndian scenario. In: Background Paper Prepared by FICCI, International Conference onScience and Technology Capacity Building for Climate Change. New Delhi, India,pp. 5–17.

Rupakumar, K., Sahai, A.K., Krishna, K., Patwardhan, S.K., Mishra, P.K., Revadekar, J.V.,Kamala, K., Pant, G.B., 2006. High-resolution climate change scenarios for India for the21st century. Curr. Sci. 90, 334–345.

Salinger, M.J., 1989. The effects of greenhouse gas warming on forestry and agriculture. DraftReport for WMO Commission of Agrometeorology.

Sathaye, J., Shukla, P.R., Ravindranath, N.H., 2006. Climate change, sustainable develop-ment and India: global and national concerns. Curr. Sci. 90, 314–325.

SenRoy, S., Balling, R.C., 2005. Analysis of trends inmaximum andminimum temperature,diurnal temperature range, and cloud cover over India. Geophys. Res. Lett. 32, L12702.

Seneweera, S.P., Conroy, J.P., 1997. Growth, grain yield and quality of rice (Oryza sativa L.) inresponse to elevated CO2 and phosphorus nutrition. Soil Sci. Plant Nutr. 43, 1131–1136.

Septiningsih, E.M., Pamplona, A.M., Sanchez, D.L., Neeraja, C.N., Vergara, G.V.,Heuer, S., Ismail, A.M., Mackill, D.J., 2009. Development of submergence tolerant ricecultivars: the Sub1 locus and beyond. Ann. Bot. 103, 151–160.

Sharma, H.C., 2013. Climate change effects on insects: implications for crop protection andfood security. In: Kang, M.S., Banga, S.S. (Eds.), Combating Climate Change: An Agri-cultural Perspective. CRC Press, Boca Raton, pp. 213–236.

Sharma, S.K., Chauhan, R., 2011. Climate change research initiative: Indian network forclimate change assessment. Curr. Sci. 101, 308–311.

Sharma, V.K., Thind, T.S., Singh, P.P., Mohan, C., Arora, J.K., Raj, P., 2007. Disease-weather relationships and forecasting of bacterial leaf blight of rice. Plant Dis. Res.22, 52–56.

Sharma, B.R., Rao, K.V., Vittal, K.P.R., Ramakrishna, Y.S., Amarasinghe, U., 2010. Esti-mating the potential of rainfed agriculture in India: prospects for water productivityimprovements. Agric. Water Manage. 97, 23–30.

Shin, J.W., Yun, S.C., 2010. CO2 and temperature effects on the incidence of four majorchili pepper diseases. Plant Pathol. J. 26, 178–184.

Sinha, S.K., Swaminathan, M.S., 1991. Deforestation, climate change and sustainable nutri-tion security: a case study of India. Climate Change 19, 201–209.

Sinha, S.K., Singh, G.B., Rai, M., 1998. Decline in Crop Productivity in Haryana and Pun-jab: Myth or Reality? Indian Council of Agricultural Research, New Delhi, India.

Sontakke, N.A., 1990. Indian Summer Monsoon Rainfall Variability During the LongestInstrumental Period 1813–1988. M.Sc. Thesis, University of Poona, Pune, India.

Srivastava, C.P., Joshi, N., Trivedi, T.P., 2010. Forecasting ofHelicoverpa armigera populationand impact of climate change. Indian J. Agric. Sci. 80, 3–10.

Staley, J.T., Hodgson, C.J., Mortimer, S.R., Morecroft, M.D., Masters, G.J., Brown, V.K.,Taylor, M.E., 2007. Effects of summer rainfall manipulations on the abundance and ver-tical distribution of herbivorous soil macro-invertebrates. Eur. J. Soil Biol. 43, 189–198.

Sultana, S., Khew, C.-Y., Morshed, M.M., Namasivayam, P., Napis, S., Ho, C.L., 2012.Overexpression of monodehydroascorbate reductase from a mangrove plant(AeMDHAR) confers salt tolerance on rice. J. Plant Physiol. 169, 311–318.

Swaminathan, M.S., 2012. Remember your Humanity: Pathway to Sustainable Food Secu-rity. New India Publishing Agency, New Delhi.

Swaminathan, M.S., Kesavan, P.C., 2012. Agricultural research in an era of climate change.Agric. Res. 1, 3–11.

Tao, L.X., Tan, H.J., Wang, X., Cao, L.Y., Song, J., Cheng, S.H., 2008. Effects of high-temperature stress on flowering and grain-setting characteristics of Guodao 6. ActaAgron. Sin. 34, 609–674.
























































Taub, D.R., Wang, X.Z., 2008. Why are nitrogen concentrations in plant tissues lowerunder elevated CO2? A critical examination of the hypotheses. J. Integr. Plant Biol.50, 1365–1374.

Tobin, P.C., Nagarkatti, S., Loeab, G., Saunders, M.C., 2008. Historical and projected inter-actions between climate change and insect voltinism in a multivoltine species. Glob.Chang. Biol. 14, 951–957.

UNEP, 1989. Criteria for assessing vulnerability to sea level rise: a global inventory to highrisk areas. United Nations Environment Programme and the Government of theNetherlands. Draft Report.

Vanaja, M., Raghuram, R., Lakshmi, N.J., Maheswari, M., Vagheera, P., Ratnakumar, P.,Jyothi, M., Yadav, S.K., Venkateswarlu, B., 2007. Effect of elevated atmospheric CO2

concentrations on growth and yield of blackgram (Vigna mungo L. Hepper): a rainfedpulse crop. Plant Soil Environ. 53, 81–88.

Venkateswarlu, B., Shanker, A.K., 2009. Climate change and agriculture: adaptation andmitigation strategies. Indian J. Agron. 54, 226–230.

Venkateswarlu, B., Singh, A.K., Prasad, Y.G., Ravindra Chary, G., Srinivasarao, C.,Rao, K.V., Ramana, D.B.V., Rao, V.U.M., 2011. District Level Contingency Plansfor Weather Aberrations in India. Central Research Institute for Dryland Agriculture,Natural Resource Management Division, Indian Council of Agricultural Research,Hyderabad, India.

Vu, H.T.T., Manangkil, O., Mori, N., Yoshida, S., Nakamura, C., 2010. Post-germinationseedling vigor under submergence and submergence-induced SUB1A gene expression inindica and japonica rice (Oryza sativa L.). Aust. J. Crop Sci. 4, 264–272.

Watson, R.T., Zinyowera, M.C., Moss, R.H. (Eds.), 1998. The Regional Impacts of Cli-mate Change: An Assessment of Vulnerability. Cambridge University Press, Cambridge,pp. 517, IPCC II report.

World Meteorological Organization, 1992. International Meteorological Vocabulary. sec-ond ed., WMO, Geneva, Switzerland.

Xu, K., Xu, X., Fukao, T., Canlas, P., Rodriguez, R.M., Heue, S., Ismail, A.M., Bailey-Serres, J., Ronald, P.C., Mackill, D., 2006. Sub1A is an ethylene-response-factor-likegene that confers submergence tolerance to rice. Nature 442, 705–708.

Yin, X., Struik, P.C., 2008. Applying modelling experiences from the past to shape systembiology: the need to converge crop physiology and functional genomics. New Phytol.179, 629–642.

Yoshida, S., Parao, P.T., 1976. Climatic influence on yield and yield components of low landrice in tropics. In: Proc. Symposium on Climate and Rice. International Rice ResearchInstitute, Manila, Philippines, pp. 471–494.

Ziska, L.H., 2003. Evaluation of the growth response of six invasive species to past, presentand future atmospheric carbon dioxide. J. Exp. Bot. 54, 395–404.

Ziska, L.H., Goins, E.W., 2006. Elevated atmospheric carbon dioxide and weed populationsin glyphosate treated soybean. Crop. Sci. 46, 1354–1359.

Ziska, L.H., Teasdale, J.R., 2000. Sustained growth and increased tolerance to glyphosateobserved in a C3 perennial weed, quackgrass (Elytrigia repens), grown at elevated carbondioxide. Aust. J. Plant Physiol. 27, 159–166.

Ziska, L.H., Namuco, O., Moya, T., Quilang, J., 1997. Growth and yield response of field-grown tropical rice to increasing carbon dioxide and air temperature. Agron. J. 89,45–53.

Ziska, L.H., Tomecek, M.B., Gealy, D.R., 2010. Competitive interactions between culti-vated and red rice as a function of recent and projected increases in atmospheric carbondioxide. Agron. J. 102, 118–123.





















































[advances in agronomy] volume 123 || global warming and its possible impact on agriculture in india

Documents