10th JIRCAS Symposium, 55-62

Environmental Changes and Food Production in Asia

Okammoto, Katsuo', Junko Shindo', Hideshige Toda* and Hiroyuki Kawashima'

ABSTRACT

As a result of climate change, the air temperature and precipitation may become unsuitable for the

cultivation of major cereals in Asia. This paper will describe the impacts of climate change on major cereal

crops in Asia such as rice, wheat and maize. Moreover, the impacts of agriculture on the environment will

also be presented. The air temperature and precipitation data from the 1961-90 mean monthly terrestrial

climatology and the results from simulation studies based on the Global Climate Model (GCM) constructed

by the Center for Climate System Research at the University of Tokyo (CCSR) were used to predict the

impacts of climate change on sustainable cropping and agricultural development. Changes in the mean air

temperature and precipitation in the major cereal-producing regions in different cropping seasons were

predicted from the present through the 2090s. Climate change will generally increase both the air temperature

and precipitation in Asia. The impacts of climate change could be either beneficial or harmful. The increase in

air temperature and precipitation will be disadvantageous to wheat cropping in Asia, while those will be

advantageous to rice-cropping during the cooler or dry season. In contrast, some regions in subtropical Asia

will have excess water resources during the rainy season. Precautionary measures against flooding will be

needed in these areas. Major river basins with rice-cropping zones from East to South Asia were also

investigated. Possible changes in water quality in the future were evaluated. The data used included those on

the course of a river, land-use/land-cover classification, population, climate, nitrous oxide (NOX) emission,

and country boundary. Statistical data on rice yield, harvested area, fertilizer consumption, food production,

food consumption and food trade were also used to construct nitrogen load maps. The nitrogen load changes

seasonally depending on the cropping systems used and precipitation. In the future, nitrogen discharge from

humans and fertilization will increase along with the increase in the population and cultivation intensity.

Fertilization and deposition of NOX will also increase along with economic growth. Therefore, it is likely that

the nitrogen concentration in river water will increase. Excessive irrigation and fertilization in the dry season

will result in further deterioration of the water quality, leading to the development of nonsustainable

ecosystems in river basins.

IMPACTS OF CLIMATE CHANGE ON AGRICULTURE

Asians now make up 55% percent of the world population, and this figure is rising (Fig. 1). Farmers are

increasing rice production in Asia to feed this growing population (Fig. 2) and expanding the area of irrigated

farmlands to cultivate more rice (Fig. 3).

The effect of climate change on agriculture remains an open question. Will the changes in air

temperatures and precipitation in Asia benefit major cereal cultivation, or will they make conditions

unsuitable for cultivation? To investigate this question, we assessed the air temperature and precipitation in

Senior Researcher, National Institute of Agro-Environmental Sciences, Japan t Senior Researcher, National Institute of Agro-Environmental Sciences, Japan t Professor, Shinshu University, Japan 1 Associate Professor, the University of Tokyo, Japan

55

Environmental Changes and Food Production in Asia - Okammoto, Katsuo, Junko Shindo, Hideshige Toda and Hiroyuki Kawas/z,i),i11mia1.-_:=====:::i

= 0 0 .... ~

~ .: " '3 "" ..

Po.

" ..:::: 0 0 0

2:':.

" <I ... " .§ ;; -~ .~

S IO 6

6 10 6

4 10 6

2 10 6

3 HY

2 10

Hf

C "' "'

Year

[J Othvrs

Cl • C<Bbod ia • China

Cl • Indonesia

m J"""' m K,,n·;1. !~'Ill l't ,pit·· :- R,·p II K ,re:1 . Ri,.,::,ub! 1c f

Cl • M.ala)·~ia Cl • • Myam:ar

Cl a • Ph.ilit}()il't<'S • Sin [J ,. '

• Thai land I]

Fig. 1. Population in Asia and the world

~ ~ I=: f!: i:e ~ i ~ ; "' "' "' "' "' "' Year

gi ..... "' "' "' "'

[J Ot! ·t

• \'id Na.a • Th:l.i land

• Sri Lanka • Ph i I i1191rn·:.

Cl a • J.iyan::ar [J I.: Ii a

• Wahy~,a

• Laos a Kon•;t, ~uhl iC' " ' • Korea. Dem People' s Rl"P

1B Japan • Ind llt:..,1a

Cl a [hina • Cad>odia Cl ~ • a

Fig. 3. Area of irrigated fields in Asia and the world

7,000

6,000

5,000

4,000

3,000

2,000

1,000

0

----=---~ /

/

T

I -,--,

-+-N. Hcfei 1

--N. Hcfei 2

-+-W. Guangzhou 1

--w. Guangzhou 2

-+-Punjab 1

--Punjab 2

--Upper limit of potential zone Upper limit of suitable zone

--Lower limit of suitable zone

--Lower limit of potential zone

IJ Oiht-r,

• Viet K.m

16' • Thailand 6 • Sr i Lanka

• I'hilippirn ... I] I]

16' • llyan:ur

4 I] V lo.

• V L\ .. 1,1

• Laos

II l\ .. r, ,. Rt'S)\Jb) IC o(

16' l!I h,,r '· !t.;:'l:IP pl l··.., R r

2 • J~, n

• !JIU\f\C."Sl3

I]

l!I ( h. 1

• C'ad>od ia

"' "' "' ..... "' "' Cl

"' "' "' ..... ..... "' "' "' gi :;; • Bangladt><J\

"' "' "' "' "' "' "' "' "' "'

Year

Fig. 2. Rice production in Asia and the world

Northwest of Chongqing, Chino. S:ll'~

Punjab (North of D1!lhi), (rice & whl!ot) India (twice rict +)· ,

Wtst of f aisolo.bod, Poi(isto,i (whl!at)

South of Fcuolobod, Pd(.iston (r'ice&wheat)

Pradesh I ndio(ri

North r,f Chr,rigqing, Nr,rthwest of Cho.ngchun, China tm~t China A.ff~ti!§

(111h,ct/r,ther) Harbin,Chino t'Jft:1,fi, (wheat/mci:ze)

of Guangzhou, hino a;ma wicl! rice •)

Fig. 4. Test sites for assessing climate change

3000

2500

2000

1500

1000

500

0 -------~-----

-+-N. Hefei 1

--N. Hefei 2

-+-W. Guangzhou 1

--W. Guangzhou'

-+-Punjab 1

- - Punjab2

Lower limit of suitable zone

--Lower limit of potential zone

Fig. 5. Climate change of Punjab, Hefei and Guangzhou: (a) Air temperature and (b) precipitation

56

10th JIRCAS Symposium

present-day croplands in Eastern through Southern Asia during the major cropping seasons (Okamoto et al.

2001).

DATA AND METHODS

The major cereals covered in the study were rice, wheat, and maize. Two crop calendars were employed to determine the cropping seasons: The "Country Rice Facts" (Crop and Grassland Service 2000) issued by

the Food and Agriculture Organization of the United Nations (FAO), and the "Major World Crop Areas and

Climactic Profiles" (World Agricultural Outlook Board 1994) for wheat and maize cropping areas.

The Basins and courses of rivers were determined on the basis of "Total Runoff Integrating Pathways (TRIP) data (0.5-degree grid cell version)" (Oki and Agata 1997).

The changes in the air temperature and precipitation were forecasted from the present to the final decade

in this century (2090s), assuming that the cropping season was to remain unchanged.

Data on agroclimactic zones (Bachelet and Kropff, 1995) and crop climates (Cui 1994) were used to

determine the potential and suitable zone for cultivating major cereal. The mean monthly temperature and precipitation from 1961 to 1990 were taken from data on monthly terrestrial climatology (New et al. 1999).

Decadal mean values from the 2000s to 2090s were taken from a simulation study by the Center for Climate System Research (CCSR) of the University of Tokyo.

Test sites were distributed all throughout Asia and used for the cultivation of different types and

combinations of crops, namely, for double-crop rice-cropping, single-crop rice-cropping, rice- and wheat­cropping, and spring wheat- or maize-cropping (Fig. 4).

IMPACTS OF CLIMATE CHANGE TO MAJOR CROPPING AREAS

In Punjab, Hefei, and Guangzhou, the double-crop rice-cropping areas, the air temperature is predicted

to increase and the precipitation is predicted to oscillate (Fig. 5). The air temperature will rise above the upper limit of the suitable range for rice cultivation. No upper limits have been established for precipitation, though Punjab faces the threat of flooding from the months of June to October.

In Dhaka and Bangkok, the single-crop rice-cropping areas, the conditions will vary (Fig. 6). The air

7000

6000

5000

4000

3000

2000

1000

0

-t-Dhaka I 4.000

-t-Dhaka I .--+-I"" 3,500

- Dhaka2 3,000 - Dhaka 2

--------- -t-N. Bangkok I 2,500

~ - N. Bangkok 2 2,000 -t-N. Bangkok I

~ - 1,500 - Upper limit of - N. Bangkok 2

potential zone 1,000 Upper limit of suitable zone 500 Lower limit of

suitable zone - Lower limit of 0

suitable zone - Lower limit of - Lower limit of ~~ ~', ~c, hi;:)' ~~', R'.>°' potential zone

b'-: ~ '; "'l;:)"3 "ii;:) "ii;:) "'l;:)Cj potential zone c; V V t S

" Fig. 6. Climate change of Dhaka and Bangkok: (a) Air temperature and (b) precipitation

57

Environmental Changes and Food Production in Asia - Okammoto, Kat.mo, Junko Shindo, Hideshige Toda and Hiroyuki Kawashimaa.-======::::i

35

30

25

20

15

IO

5

0

~ N\V. Changchun (wheat)

~ Harb in (maize)

- Upper limit of potent ial (s•wheat)

Upper limit of sui1able (s -wheat)

- Lower limit of suitable (s-wheat)

- Lower limit o f potent ial (s-whem)

- Upper limit of potent ial (maize)

Upper limit of suitable (maize)

- Lower limit of sun able (maize)

- Lower hmit of potential (maize)

1200

1000

800

600

400

200

0

~ NW. Chat1b,chun

(wheat)

-+- Harbin (maize)

- Upper limit of potent ial (s-wheat)

- Upper limit of suitable (s-wheat )

Lower limit of suitable (s-wheat)

- Lower limit of potential (s-wheat)

- Upper limit of potent ial (maize)

- Upper limit of suitable (maize)

Lower limit of suitable (maize)

- Lower limit of potent ial (maize)

Fig. 7. Climate change of Changchun and Harbin: (a) Air temperature and (b) precipitation

temperature in Dhaka will be slightly too cold for rice cultivation during the second season, Boro (January to

April), but it will rise to the suitable zone during the first season, Aman (June to October).

The precipitation in Bangkok will stay withln the potential zone in the dry season (February to May), but

rise into the suitable zone during the main season (June to October). In the spring wheat- and maize-cropping areas, the air temperature will be unsuitably hlgh for cultivating

spring wheat, but suitable for cultivating maize (Fig. 7). The precipitation will be suitable for spring wheat

and maize at these test sites from the present to the 2090s.

Rising temperatures in the decades to come will have benefits for the rice-cropping areas in the cooler

seasons, and drawbacks for the wheat cropping areas. The rises in precipitation due to climate change will

also have benefits and drawbacks.

IMPACTS OF AGRICULTURE ON THE ENVIRONMENT

The total area of arable cropland has steadily increased throughout the world over the past 300 years

(Ramankutty and Foley 1999). The population in Asia has steadily expanded, as mentioned earlier, and both irrigated croplands and

agricultural production have been increased to feed

the growing numbers of people (Figs. 1, 2 and 3). The

effects on the environment are considerable.

The consumption of nitrogen (N) fertilizer, for

example, has risen more than eightfold since 1961

(Fig. 8), posing considerable problems for water

supplies. Japan now consumes an average of 100 kg

of N equivalent per hectare (ha) of farmland, while

farms in China and Western Europe consume more

than 100 kg ha-1. The average yield per unit area in Western Europe is 10 t ha-1 , while that in China is

only about half of that level, i.e., 5 t ha-1. This means

that the nitrogen fertilizer used in China discharges

into the environment at a higher rate than that in

58

I 108 CJ °""" D

• Ca:rbod i a

J 8 10

7 • China

CJ

• Indones ia

= 6 to' II Japan = = • Korea. Dell Peop le' s Rep ... ..!'.L II Korea. Flepubl 1c of

ll 4 to' • Loos

i • lrb l ays1a

CJ

• Myarmar ~

2 to' D [J Pak:rstan

• Phili ppines

• Si ngapore

D

~ ~ ~ ~ ~ ~ ~ • Tha i lard ~ ~

~ ~ - ~ ~ • Viet Nam

Year

Fig. 8. Nitrogen fertilizer consumption in Asia and the world

Western Europe (Kawashima and Okamoto 1999).

The average value in Southeast Asia is reported

to be 70 kg N ha-1 (Kaewthip et al. 2003). In some

areas in China, 500 to 1900 kg N ha-1 is consumed

(Zhang et al. 1996). The consumption level in Japan

stands at 400-1560 kg N ha-1 (Tokuda and Hayatsu

2001).

As mentioned previously, the nitrogen load from

fertilizer has a considerable impact on the quality of

water and may even compromjse the safety of water

supplies for irrigation and drinking (Okamoto et al.

2003). Our group constructed a nitrogen load map

based on measurements of nitrogen concentrations in

major river basins in continental Asia (Fig. 9) .

Nitrogen levels in water are regulated quite

s trictly in Japan. The upper limit of quali ty for

10th JIRCAS Symposium

Fig. 9. Major river basins in continental Asia

drinking water in Japan is 10 ppm. Within the river basins tested in our research, nitrogen concentrations

were very low at lower altitudes, but high at higher altitudes (Table). The concentrations were very low in all

the test sites measured in Thailand, Vietnam, and Laos, and in some test sites measured in China. In many

other points in China, however, the nitrogen levels were very hlgh (Shindo et al. 2003). At a vegetable farm

in Laixi, for example, the concentration in groundwater reached 273 ppm, and a nearby suppl y of

groundwater for drinking had a very high concentration as well.

Humans and farmlands occupy very important positions within the nitrogen flow, both outputting

nitrogen load directly to the environment. Humans take nitrogen inputs from crops and output it back to

agricultural land and the environment. Farmlands receive nitrogen inputs through biofixation and

fertilization, and output nitrogen in crops.

Based on this model of nitrogen flow and environmental load in food production, our group simulated

Table. NOJ.N concentrations (ppm) of river water and groundwater in Asia

Location

Can Tho, Vietnam (Mekong Delta)

Vientiane, Laos (Mekong River)

Vientiane, Laos (groundwater)

Khan Kaen, Thailand (Ubon Rat Dam Reservoir)

Khan Kaen, Thailand (Chi River)

Nakhon Ratchasima, Thailand (Ton Sawar River)

Jinan, China (Ye11ow River)

Jinan, Chlna (groundwater, hotel)

Laixi, China (vegetable farm)

Laixi, China (Sanxi Reservoir)

Laixi, China (groundwater, farmhouse)

Qingdao, China (groundwater, farmhouse)

Qingdao, China (Laoshan, mineral water)

Qingdao, China (groundwater, farmhouse)

Qufu, China (river water)

59

cone.

0.13

0.12

0.13

0.03

0.55

0.68

3.36

11.5

273.0

0.46-0.65

89.3-120.6

22.9

12.1

3.81-3.96

43.4

Environmental Changes and Food Prod11ctio11 in Asia - Okammoto, Katsuo, J1111ko Shindo, Hideshige Toda and Hiroyuki Kawash1wini_Wia======:::i

the nitrogen load and nitrogen concentration of water at test sites from 1970 to 2050 (Fig. 10).

The nitrogen load increased rapidly in the northern part of China between the years 1970 to 2000. Over

the next half century, the nitrogen load will continue to rise in China, Vietnam, and the Philippines.

The nitrogen concentration in river water has also increased in Northern China, and it will continue to do

so. Increases in other parts of the world will probably be minimal. The increases in Northern China are the

expected result of climactic conditions, namely, poor precipitation and a low rate of denitrification due to the

low temperature in this river basin.

10 20 :» 50 100 200ppm

Fig. 10. Impacts of food production to water in Asia: (a) Nitrogen load (t year') and (b) nitrogen concentrations (NO,.N ppm)

60

10th JIRCAS Symposium

CONCLUSIONS

It was predicted that climate change will cause a gradual increase in the air temperature. Changes in the air temperature are advantageous to rice-cropping areas in the cooler season. That is, the air temperature of

Hefei and Guangzhou in the second season will reach the potential zone and the air temperature of Dhaka in

the second season will reach the suitable zone. For wheat-cropping areas, changes in the air temperature are disadvantageous. That is, the air temperature of Faisalabad, Pradesh and Changchun will be above the

potential zone. Consequently, crops cultivated in Changchun may have to be changed from spring-wheat to maize.

It was also predicted that climate change will cause an increase in precipitation. Changes in precipitation

are advantageous to rice-cropping areas in the dry season. That is, precipitation of Bangkok and Faisalabad in the dry season will in the suitable zone. However, for subtropical rice-cropping areas, changes in

precipitation are disadvantageous. That is, Punjab, Pradesh and Dhaka in the main season will be threatened

by flooding. Taking the precaution of enriching infrastructures, such as embankments and the installment of drainage pumps, will be necessary.

The amount of nitrogen load was predicted to increase from 1970 through 2050. This trend is clear in

the eastern part of China, Vietnam and the Philippines. The reason is that the amount of nitrogen fertilizer consumption is increasing.

The concentrations of nitrogen (NO,.N) was also predicted to increase from 1970 through 2050. This

trend is clear in the northern part of China. The rises will be due to the increasing usage of nitrogen fertilizer and the low precipitation in the region. The nitrogen load from farmlands will be far larger than that from

humans (settlements), due both to the increase in nitrogen fertilizer consumption and economic growth.

REFERENCES

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Change on Rice Production in Asia, edited by R. B. Matthews, M. J. Kropff, D. Bachelet and H. H. van Laar, CAB

International, Wallingford (ISBN 0-85198-959-4), 85-94.

Crop and Grassland Service, 2000, Country Rice Facts. In http:llwww.fao.org!WAICENT/FAOINFO/GRICULTIAGPC/doc/ricei11fo!

Corifa.htm, International Rice Commission, The Food and Agriculture Organization (FAQ), Rome.

Cui, D., 1994, World Agroclimate and Crop Climate, Zhejiang Science and Technology Publishing: Hangzhou (ISBN 7-5341-0656-

7) (in Chinese).

Kaewthip, J., Kawashima, H., and Ohga, K., 2003, Projection of nitrogen load from food consumption and production in Thailand. J.

Japanese Agricultural Systems Society, 19, 151-159.

Kawashima, H., and Okamoto, K., 1999, Global distribution of arable land, cereal yield and nitrogenous fertilizer use. Journal of the

Japanese Agricultural Systems Society, 15(1), 73-76.

New, M., Hulme, M., and Jones, P., 1999, Representing twentieth-century space-time climate variability. Part I: Development of a

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Okamoto, K., Yokozawa, M., and Kawashima, H., 2001, Pluses and minuses of climate change on major cereal cultivation in Asia.

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Okamoto, K., Shindo, J., and Kawashima, H., 2003, Land-use, water resources and nitrogen load in major river basins in Asia. In

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61

Environmental Changes and Food Production in Asia- Okammoto, Katsuo, Junko Shindo, Hideshige Toda and Hiroyuki:~q:n:(tshWI!

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62