Climate change and food production: Pakistan

M. Arif Goheer

Global Change Impact Studies Centre (GCISC)Islamabad – Pakistan

GECAFS IGP CPW&F and APN Launch WorkshopsKathmandu-Nepal, June 27-30, 2006

Climate Change

“the greatest challenge facing the world at the beginning of the century”

World Economic ForumDavos, Switzerland 2000

Changing Climatic Trends

• Increasing concentration of CO2 in the atmosphere

• Pre-industrial revolution (1789) 280 ppm• Present (2004) 380 ppm• Expected level (2050) 550 ppm

• Rising surface temperatures• Global Av. Temp. rise (20th century) 0.6 °C• Projections for 2100 1.4 to 5.8 °C

• Changing rainfall patterns

Source: IPCC, 2001Source: IPCC, 2001

Depending on the level of GHG emissions and concentration in the atmosphere, the average global temperature would rise between 1.4

oC – 5.8 oC over the 21st Century

Climate and Food Production

• Weather and Climate are the key factors in food productivity

• Being open to vagaries of nature, food production are highly vulnerable

to climate change phenomena

Climate Related Parameters of Agricultural Productivity

• CO2

• Temperature• Solar Radiation• Precipitation• Others (Wind speed and direction, Soil Moisture,

Water vapour, etc.)

Basic understanding of these factors helps manipulate plants to meet human needs of food, fiber and shelter The parameters also help understand impacts of climate change and devise adaptation/mitigation strategies

GDD and Corresponding GSL

Climate-Water-Food Linkages

Crop Water Demand

Water Availability

Evapo-transpiration (ET)

Agriculture (Crop Yield)

Photosynthetic Activity

Climate

Temperature RainfallWind,

Sunshine, Solar Radiation

CO2 level

Canal/ground water

Projections of IPCC for South Asia

• Increase in surface temperature will contribute to snowmelt resulting in risk of floods

• Indus river inflows will decrease by 27% by the year 2050

• Land degradation will cause land to shrink from present 0.8 ha per capita to 0.3 by 2010

• Areas in mid and high latitudes will experience increase in crop yield whereas in lower latitudes will experience a general decrease, under elevated CO2 conditions

IPCC, 2001

• Crop models showed that increase in temperature of 0.9 and 1.8°C resulted in reduction in length of wheat growing season by 4 and 8 days respectively

• At 0.9°C increase in temperature, wheat grain yield increased by 2.5% whereas at 1.8°C increase, the grain yield decreased by 4%

• The increase in temp. would reduce the productivity of rice crop due to heat stress and reduction in growing season length

Semi-arid areasSemi-arid areas

• Crop modeling studies showed a non significant trend in wheat yields under increased temperature scenarios (0.9°C and 1.8°C)

• Wheat straw yields were reduced by 7% and 12% with temperature increases of 0.9°C by 2020 and 1.8°C by 2050

Arid areasArid areas

Impacts on Food Production

Due to Increasing Temperatures

• Shift in spatial crop boundaries will have enormous economic and social impact.

e.g. Rice transplantation, Cotton picking etc.

• Increase/decrease in crop yields

• Rise in evapotranspiration rates, calling for greater efficiency of water use

• Shift in timing of developmental stages of pests in Crop-weed-pest relationships

• More dependency on ground water in the face of low precipitation

• danger of depletion of aquifer due to injudicious pumping

• increased cost of cultivation• soil salinization due to poor quality ground

water

Due to Change in Precipitation PatternDue to Change in Precipitation Pattern

Effect of water supplies

a) Decreased Surface Water Supplies

• Reduction in yield and quality of crops due to water stress during critical growth stages

• Shift in cropping patterns• Nitrogen volatilization losses from ammonical

fertilizers

b) Increased Water Supplies

• Potential development of Water logging and Salinity/Sodicity

• Denitrification losses from ammonical and nitrate based fertilizers

• Shift in cropping patterns

• Increased incidence of plant diseases

Extreme Weather Events

• In addition to changing climate, increased variability in weather may occur with consequent frequent extreme events such as heat waves, droughts, wind storms and floods having negative impacts on agriculture

Pakistan’s Resource Base

LAND (in million hectare)• Geographical area = 79.6 • Area under cultivation = 27.6% (21.87)• Crop area irrigated = 22.6% (17.99)• Rainfed Agriculture area = 4.97% (21.87)• Forest = 4.5% (3.61)• Culturable waste = 11.7% (9.31)• Range Lands = 59% (46.96)

Cropping Seasons

• Rabi• November-April

• Wheat, Lentil, Chickpea

• Kharif• May-October

• Rice, Maize, Mungbean, Cotton

Agricultural productivity

Crop Yield

Wheat 2262 kg/ha

Rice 1836 kg/ha

Maize 1768 kg/ha

Sugarcane 48.1 t/ha

Cotton 579 kg/ha

Fodder 22.3 t/ha

Agricultural Statistics of Pakistan 2001-02

Demand and Production projections with respect to climate change in

Pakistan

Commodities Baseline Requirement

Demands

(000 tonnes)

Production

(000 tonnes)

1995 2020 2050 2020 2050

Wheat 17.9 32.4 43.0 27.46 35.70

Rice 5.1 9.2 12.2 6.21 7.89

S.Cane 41.6 75.3 100.0 50.0 60.0

Cotton 1.8* 3.3* 4.4* 18.00* 25.0*

Fruits 5.1 13.8 18.3 50.0 60.0

Vegetable 4.5 12.2 16.2 20.0 50.0

Meat 2.1 5.7 7.6 5.0 14.0

Milk 15.3 41.5 55.0 50.0 125

* Million Bales Source: CICERO 2000:2

Work Done at GCISC

Wheat & Rice Simulation Results using DSSAT based CERES-Wheat &

CERES-Rice models

Semi-arid areasArid areasHumid area

Sub-humid areas

Effect of Increase in Temperature and CO2levels

on Wheat yields

Subhumid Areas

0

500

1000

1500

2000

2500

3000

3500

1˚C 2˚C 3˚C 4˚C 5˚CChange in temperature (°C)

Yie

ld (

Kg

/ha

)

Humid Areas

0

500

1000

1500

2000

2500

3000

3500

4000

4500

1˚C 2˚C 3˚C 4˚C 5˚C

Change in temperature (°C)

Yie

ld (

Kg

/ha

)

Arid Areas

0

1000

2000

3000

4000

5000

1 2 3 4 5

Change in Temperature (°C)

Yie

ld (k

g/ha

)

360 550Semi-arid Areas

0

1000

2000

3000

4000

5000

1 2 3 4 5

Change in Temperature (°C)

Yie

ld (

kg/h

a)

360 550

Effect of Increase in Temperature CO2levels and

Water Scenarios on Wheat yields

Semi Arid Areas

0

1000

2000

3000

4000

5000

1 2 3 4 5Temperature Increase (°C)

Yie

ld (

kg

/ha)

4irri_360ppm 2 irri_360ppm4irri_550ppm 2 irri_550ppm

Effect of Increase in Temperature CO2levels and

Water Scenarios on Wheat yields

Arid Areas

0

1000

2000

3000

4000

1 2 3 4 5Temperature Increase (°C)

Yie

ld (

kg

/ha)

4irri_360ppm 2 irri_360ppm4irri_550ppm 2 irri_550ppm

Effect of Increase in Temperature on Wheat GSL (DSSAT based results 1994-95 to 2003-04 for Cv. Inqalab sown on Nov. 20th)

Temperature (°C)

Growing Season Length (Days)

Humid(Shangla)

Sub Humid(Islamabad)

Semi Arid(Faisalabad)

Arid(Multan)

Baseline 246 161 146 137

1 °C (increase over baseline)

232 155 140 132

2 °C 221 149 135 127

3 °C 211 144 130 123

4 °C 202 138 125 118

5 °C 194 133 121 113

Effect of Increase in Temperature and CO2levels on Rice yields

in Semi-arid areas of Punjab

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

1°C 2°C 3°C 4°C 5°CTemperature

Yie

ld (

kg

/ha

)

375ppm 550 ppm

Baseline Yield

Effect of increase in Temperature on GSL of Rice in Semi arid areas of Punjab (Faisalabad)(Cv. Basmati Super transplanted in 1st Week of July)

Temperature Growing Season Length (Days)

Baseline 108

(increase over baseline)

1 °C 102

2 °C 100

3 °C 98

4 °C 92

5 °C 89

Conclusions• Rise in CO2 level only has positive impact on wheat yield

• Rise in Temperature shows negative impact on wheat yield• But it could be mitigated if CO2 level = 550 ppm

• Negative impact of Rise in Temperature on yield could also be mitigated by increasing number of Irrigations (but…)

• Reduction in water resources shows a negative impact on wheat yield

• Even 550 ppm CO2 level would not result in sustaining current yield level if water resources reduce

• Rise in CO2 levels could sustain the baseline Rice yields up to 1C