environmental changes and food production in asia · environmental changes and food production in...
TRANSCRIPT
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
Bachelet, D., and Kropff, M. J., 1995, The impact of climatic change on agroclimatic zones in Asia, Modeling the Impact of Climate
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
1961-90 mean monthly terrestrial climatology. Journal of Climate, 12(3), 829-856.
Okamoto, K., Yokozawa, M., and Kawashima, H., 2001, Pluses and minuses of climate change on major cereal cultivation in Asia.
In Advances in Ecological Sciences 10: Ecosystems and Sustainable Development III, edited by Y. Villacampa, C. A. Brebbia
and J-L. Us6, (Alicante: University of Alicante, Spain, and Southampton: Wessex Institute of Technology, U.K., ISBN: 1-
85312-871-6), 79-88.
Okamoto, K., Shindo, J., and Kawashima, H., 2003, Land-use, water resources and nitrogen load in major river basins in Asia. In
River Basin Management II, edited by C. A. Brebbia, (Southampton: WIT Press, U.K., ISBN: 1-85312-966-6), 423-429.
Ramankutty, N., and Foley, J. A., 1999, Estimating historical changes in global land cover: Croplands from 1700 to 1992. Global
Biogeochemical Cycles, 13(4), 997-1027.
61
Environmental Changes and Food Production in Asia- Okammoto, Katsuo, Junko Shindo, Hideshige Toda and Hiroyuki:~q:n:(tshWI!
Shindo, J., Okamoto, K., and Kawashima, H., 2003, A model based estimation of nitrogen flow in the food production-supply system
and its environmental effects in East Asia. Ecological Modelling, 169, 197-212.
Tokuda and Hayatsu, 2001, Nitrous oxide emission potential of 21 acidic tea field soils in Japan. Soil Sci. Plant Nutr., 47, 637-642.
World Agricultural Outlook Board, 1994, Major World Crop Areas and Climatic Profiles. Agricultural Handbook No. 664, U.S.
Department of Agriculture (USDA), Washington.
Zhang et al., 1996, Nitrate pollution of groundwater in northern China. Agriculture Ecosystems and Environment, 59, 223-231.
62