Climate Changes Impacts on Agriculture in China*- By top-down and bottom-up
Songcai You(1, Institute of Environment and Sustainable Development in Agriculture, the Chinese
Academy of Agricultural Sciences, Beijing 100081;)

1. Foreword
Climate change is a major global issue of common concern to the internationalcommunity. It is an issue involving both environment and development, but it isultimately an issue of development. As a developing country of responsibility, China
attaches great importance to the issue of climate change.

2. Climate Changes in China
Many observations in recent 100 years show that the earth's climate is now
experiencing significant change characterized by global warming. And the trend ofclimate change in China is generally consistent with that of global climate change.
2.1 Observed Climate Changes in China
The Third Assessment Report of IPCC has clearly indicated that most of the global
warming observed over the past 50 years was likely induced by the increase inconcentrations of greenhouse gases (GHGs), such as carbon dioxide (CO2), methane(CH4), and nitrous oxide (N2O), due to human activities.
2.1.1 Changes in Past 100 Years
In the context of global warming, climate in China has experienced noticeablechanges over the past 100 years as well. The major observed evidence of climatechange in China includes the following:(1) Temperature
Annual average air temperature has increased by 0.5~0.8 during the past 100 years,
which was slightly larger than the average global temperature rise. Most of thetemperature rise was observed over the last 50 years. The regional distribution of thetemperature changes shows that the warming trend was more significant in western,
eastern and northern China than in the south of the Yangtze River. The seasonal
distribution of the temperature changes shows that the most significant temperature
increase occurred in winter, and 20 consecutive warm winters were observed
nationwide from 1986 to 2005;(2) Precipitation
In the past 100 years, there was no obvious trend of change in annual precipitation in
China, but there exists considerable variation among regions. The annual precipitation
decreased gradually since 1950s with an average rate of 2.9 mm/10a, although it* yousc@ieda.org.cn, No.12, South Zhongguancun Street, Haidian District, Beijing 100081, Tel:+86(0)10-8210-9571 ext. 3227

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increased slightly during the period of 1991 ~ 2000. The regional distribution of
precipitation shows that the decrease in annual precipitation was significant in most ofnorthern China, eastern part of the northwest, and northeastern China, averaging
20~40 mm/10a, with decrease in northern China being most severe; while
precipitation significantly increased in southern China and southwestern China,
averaging 20~60 mm/10a.
2.1.2 Changes in Past 50 Years
Based on the 1961-2007 ground surface meteorological data from 558 meteorologicalstations in China, the differences of agricultural climate resources in China different
regions were analyzed, and the change characteristics of the agricultural climate
resources in 1961- 1980 (period I) and 1981-2007 (period II) were compared, taking
the year 1981 as the time node. As compared with period I, the mean annual
temperature in China in period II increased by 0.6 ℃, the highest increment occurredin Northeast China. The annual sunshine hours decreased by 125.7h, the highest
decrement occurred in the middle and lower reaches of Yangtze River, and followedby the North China; Both precipitation and reference crop evapotranspiration showeda decreasing trend, with the largest decrement of precipitation in North China and ofreference crop evapotranspiration in the middle and lower reaches of Yangtze River.
Table 1 Observed climate changes from 1961-2007 in China
Climate element

SWChinaMiddle and SouthLower
China
Yangtze River(℃)
0.4
0.4
0.4
Annual mean
temperature
(%)
2.9
2.5
1.9(h) -93.9-199.1-159.1
Annual sunshine hours
(%)
-5.0
-10.3
-8.5(mm) -13.7
46.6
22.8
Annual precipitation(%)-1.43.7
1.4-34.5-22.3
Annual reference crop (mm) -22.1
evapotranspiration
(%)
-2.2
-3.4
-1.9

NWChina

NorthChinaNE
China

China

0.7
11.8
-67.3
-2.3
3.4
1.3
-30.9
-2.9

0.7
7.1
-174.3
-6.5
-41.4
-7.2
-33.3
-3.2

1.0
24.4
-101.9
-3.8
5.0
0.9
-11.6
-1.4

0.6
5.5
-125.7
-5.3
3.1
0.4
-26.4
-2.6

2.1.3 Changes of Agro-Climate in past 50 years in China
Also, based on the 1961-2007 ground surface meteorological data from 558
meteorological stations in China, the change characteristics of the agricultural climate
resources in 1961- 1980 (period I) and 1981-2007 (period II) were compared. As
compared with period I, the ≥0℃ active accumulated temperature representing thegrowth periods of chimonophilous crops and the ≥10℃ active accumulated
temperature representing the growth periods of thermophilic crops increased
averagely by 123.3 ℃·d and 125.9 ℃·d, respectively. The ≥10℃ active accumulated
temperature increased most in South China. In sunshine hours in the growth periodsof chimonophilous crops and of thermophilic crops in period II decreased by 32.2 h
and 53.6h, respectively, compared with those in period I. Both the precipitation andthe reference crop evapotranspiration in China all showed a decreasing trend, with thelargest decrement in North China; the largest decrement in the reference crop
evapotranspiration in the growth periods of thermophilic crops and of chimonophilous
crops occurred in the middle and lower reaches of Yangtze River and in Northwest
China, respectively.
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Table 2 Observed agro-climate changes from 1961-2007 in China
Agricultural climate elementItem
During the period
Unitof daily
temperature
(℃.d)
≥0℃
Accumulated(%)
temperature
(℃.d)
≥10℃
(%)
(mm)
≥0℃
(%)
Precipitation
(mm)
≥10℃
(%)
(h)
≥0℃
(%)
Sunshine
hours
(h)
≥10℃
(%)
(mm)
Reference
≥0℃
(%)
crop
evapotranspi
(mm)
≥10℃
ration(%)

Southwest
China

Middle and lower
Yangtze RiverSouth
China

Northwest
China

North
China

Northeast
China

China

100.9
2.6-13.6
-1.6
-46.9
-4.4
-6.5
-0.9

123.5
2.4
16.6
1.6
-114.6
-8.1
-21.6
-2.6

178.2
2.5
6.60.4-115.5
-6.8
-9.4
-0.9

120.0
3.7
105.2
4.0
1.2
0.5
6.1
4.0
-3.1
-0.2
-1.4
-0.1
-20.0
-2.2
-13.0
-1.9

118.1
2.9
131.5
3.6
-33.9
-7.4
-30.3
-7.3
-93.6
-4.9
-69.4
-4.8
-15.9
-1.8
-8.0
-1.1

140.4
5.2
7.7
1.7
-18.7
-1.6
2.4
0.6

123.3
3.5
125.9
3.2
-9.9
-3.0
-0.6
-0.1
-32.2
-1.7
-53.6
-4.1
-19.2
-2.1
-10.7
-1.4

“-” meant no data3

2.1.4 Changes of Water Resources
Climate change has already caused the changes of water resources distribution overChina. A decreasing trend in runoff was observed during the past 40 years in the six
main rivers, namely Haihe River, Huaihe River, Yellow River, Songhuajiang River,Yangtze River, and Pearl River. Meanwhile, there is evidence for an increase infrequency of hydrological extreme events, such as drought in North and flood inSouth. The Haihe-Luanhe River basin is the most vulnerable region to climate change,
followed by Huaihe River basin and Yellow River basin. The arid continental river
basins are particularly vulnerable to climate change. In the future, climate change will
have a significant impact on water resources over China: in the next 50-100 years, themean annual runoff is likely to decrease evidently in some northern arid provinces,such as Ningxia Autonomous Region and Gansu Province, while it seems to increase
remarkably in a few already water-abundant southern provinces, such as Hubei andHunan provinces, indicating an increase of flood and drought events due to climatechange; the situation of water scarcity tends to continue in the northern China,
especially in Ningxia Autonomous Region and Gansu Province, where water resource
per capita are likely to further decrease in future 50-100 years; providing that waterresources are exploited and utilized in a sustainable manner, for most provinces, watersupply and demand would be basically in balance in future 50-100 years. However,gap between water resource supply and demand might be expanded in Inner Mongolia
Autonomous Region, Xinjiang Autonomous Region, Gansu, and Ningxia
Autonomous Region.
Table 3 Linear trends in basin-averaged annual and seasonal precipitation (mm) overten major river catchments and China 1956-2002
Watershed
WinterSpringSummerFall
YearlySonghuajiang River
-0.08
-0.01
-0.03
-0.11
-0.06
Liaohe River
-0.09
0.03
-0.12
-0.12
-0.15*
Haihe River
-0.07
0.01
-0.16*-0.08-0.17*
Huaihe River
0.07
-0.07
-0.11*-0.13-0.14*
Yellow River
0.02
-0.05
-0.10
-0.11
-0.14*
Yangtze River
0.06
-0.03
0.06
-0.04
0.03
Rivers in Southeast region
0.07
0.00
0.19**-0.09
0.11
Rivers in Northwest Region
-0.02
0.03
0.08*
0.07
0.10*
Rivers in Southwest Region
0.05
0.15**-0.02
0.09*
0.09**
Pearl River
0.08
0.04
0.05
-0.02
0.08
China
0.01
0.01
0.02
-0.02
0.01
Note: ** and * stand for the test passing at 0.01 level and 0.05 level, respectively.

2.1.5 Changes of Extreme Climate Events
The frequency and intensity of extreme climate/weather events throughout China haveexperienced obvious changes during the last 50 years. Drought in northern andnortheastern China, and flood in the middle and lower reaches of the Yangtze Riverand southeastern China have become more severe. The annual precipitation in mostyears since 1990 has been larger than normal, with the precipitation pattern being adipole, corresponding to frequent disasters in the North and flood in the South; thefrozen occurred in South China in 2008 caused serious damage. According to survey,
the direct damage to agriculture and forest is nearly 200 billions RMB Yuan, of which,the damage to food crops occupied one third. Nearly 80 millions livestock died fromthe cold.

4Table 4 Damaged area of food crops and economic crops (in 1000 ha)
Food crops Rape Vegetable Fruit Tea
Area with 10%-30%14667
3891
3189
1930 439
decrease of yield
Area with 30%-70%
8000
2149
1583
801 185
decrease of yield
Area with over 70%
2051
375
583
232
25
decrease of yield* only the damage in Guangxi Zhuangzu Autonomous Region

Sugar cane*
755
491
71

2.1.6 Identification of Adaptation Strategies in Specific Region
The MOST of China set up a special sector of climate change impact study inNational 973 program. Besides, the MOA, Bureau of Forest of China also raised
special fund to support the studies on climate change impacts. The research area
covers the Carbon sources and sink, the mechanism of climate change, impacts ofclimate change on agriculture, forestry, livestock, fishery, human being, etc. special
attentions have been paid to the vulnerable areas such as coastal area, the environmentfragile areas. As water shortage is the key problem in China, and over 70% of water
resources is used by agricultural sector. It attracted the attention of scientists fromdomestic and abroad.
The most widely used adaptation strategies include water saving techniques inagriculture, sustainable management of water resources, limitation of undergroundwater exploitation, change planting date, etc..
Table 5 Case studies for testing the adaptation assessment and management
framework
Case Study
AreaHuaiheRiver
Watershed

Objectives

Miyun
Reservoir,
located inHaihe
River
Watershed

Sustainablewatersupply toBeijing

To reduce
the damages
fromflooding
disaster

Existing
Problems
Flooding
disasterSponsor

Identified Strategies

World Bank andMinistry of
Water Resources

Continued
reduction of
inflow water

Ministry ofEnvironment
Protection,
Ministry of
Water Resources,
World Bank,
GlobalEnvironment
Fund, thegovernment of
Beijing

1, enhance the construction ofdrainage system in lowland
area;
2, increase water holding
capacity
3, establish the flooding
forecast system and water
resource management system.
1, Transform the irrigatedcultivation to rain fed
cultivation in upper reach of
Miyun Reservoir;
2, Financial compensation to
the farmers in the upper reach
3, Increase the inflow water byconstructing a watertransporting channel from
Luanhe River to ChaoheRiver in the upper reach of
Miyun Reservoir;

5HaiheRiver
Watershed

Agricultural
water
resources
and policies

Shiyangheriver
watershed

Sustainable
managementof water
resources

Decreasing
undergroundwater level,groundsubsidence,degradation ofwater quality.
Oasis
disappear duetoEnvironmental
degradation

Ministry ofWater Resources,World BankManagement
Bureau ofShiyanghe riverwatershed

4, Increase water use efficiency
by reusing the waster water.
1, Raise water price,
2, Increase investment on
irrigation and drainage system.

1, Increase investment on watersaving project2, transfer water from Yellow
river to Shiyanghe river,
3, Financial compensation tolose caused by limiting theunderground water
exploitation.

2.2 Trend of Climate Change in China
The trend of climate warming in China will further intensify in the future. The
projections by Chinese scientists indicate that:(1) Temperature
The nationwide annual mean air temperature would increase by 1.3~2.1C in 2020 and2.3~3.3C in 2050 as compared with that in 2000. The warming magnitude would
increase from south to north in China, particularly in northwestern and northeastern
China where significant temperature rise is projected. It is estimated that by 2030, theannual temperature would likely increase by 1.9~2.3C in northwestern China,
1.6~2.0C in southwestern China, and 2.2~2.6C in the Qinghai-Tibetan Plateau;(2) PrecipitationIt would possibly increase during the next 50 years in China, with a projectednationwide increase of 2~3 percent by 2020 and 5~7 percent by 2050. The mostsignificant increase might be experienced in southeastern coastal regions;(3) Extreme climate/weather events
The possibility of more frequent occurrence of extreme weather/climate events would
increase in China, which will have immense impacts on the socio-economic
development and people's living;(4) Desertification
The arid area in China would probably become larger and the risk of desertification
might increase;

3. Climate Change Impacts on Rice, Wheat and Corn in China
There are many researches on climate changes impacts on crops. Here, I would like tointroduce two newly launched research projects which I participated in.

6(1) Sensitivity, vulnerability of rice in south China under climate changeThis is one of tasks of project, launched in 2011 and entitled The influence of globalchange on vulnerability and adaptivity of major terrestrial ecosystems in China,
funded by The National Basic Research Program (also called 973 Program). ThePreliminary output are as followings.
-The distribution of rice cropping system: region I is for double rice in thecoastal area of south China; region II and III are for single rice and double
rice in the other part of south China and central China, the difference between
two regions is region III with high elevation. Region IV, V and VI are forsingle rice.

Double rice in south China
Double rice and single rice and Central China
Single rice and double rice in SW China
Single rice in North China
Single rice in NE China
Single rice in semi-arid region in NW China-The spatial distribution of rice area. Most of rice cultivation is in the south ofYangtze rive and area along the north bank of Yangtze river

Intensive
Scattered7

-Experiment site: Jingzhou, Hubei province, located in Jianghan plain inCentral China.

-Three treatments, each with three replicates. Treatment I: CK; Treatment II:increasing temperature by 2℃; Treatment III: increasing temperature by 2℃
and CO2 by 60 ppm.

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-Results of different treatment
120

100
110
100

80
7060

晚稻株高（ cm）

早稻株高（cm）

90

CK50

增温2℃

40

增温2℃+增60ppmCO290
80

CK70

增温2℃
增温2℃+60ppmCO2603050

20510152025 30 35 40
移栽天数（d）

455055604001020304050
移栽天数（d）

60

Figure 1 growth days and height (left, early rice; right, late rice)

970

80

90

350

14.0300

12.0250

分蘖数（茎/m2 ）每穴分蘖数（茎/穴）

16.0

10.0
8.0
6.0

CK
增温2℃
增温2℃+增60ppmCO24.0

200
CK

150

增温2℃

100

增温2℃+60ppmCO250

2.0

0

0.0
10152025
早稻移栽后天数（d）

30035

510152025

3035

晚稻移栽天数(d)Figure 2 growth days and Number of tillers (left, early rice; right, late rice)5053.0

叶片叶绿素含量（ SPAD）

52.0

叶绿素相对值51.0
50.0
49.0
CK

48.0

增温2℃

47.0

增温2℃+增60ppmCO245
40
35
CK

30

增温2℃
25

增温2℃+60ppmCO246.0

2045.0分蘖期拔节期孕穗期

抽穗期

扬花期

0

乳熟期

2040

6080

100

晚稻移栽天数（d）

早稻生育期

Figure 3 growth days and Chlorophyll content (left, early rice; right, late rice)
1400

25000
CK
增温2℃

1000

地上部生物量（ kg/hm 2 ）生物量（g/m2)1200

增温2℃+增60ppmCO2

800
600
400

20000

CK
增温2℃

15000

增 温 2℃ +60ppmCO2

10000
5000

200
00
分蘖期

拔节期孕穗期

分蘖期

完熟期

孕穗期抽穗期

完熟期

晚稻生育期

早稻生育期

Figure 4 growth days and biomass (left, early rice; right, late rice)
Table 6 Properties of Yield
CK+2℃+2 ℃ +
CK
60ppmCO2+2℃+2℃+60ppmCO2

Tillers

12.7

13.9

13.7

16.1

15.7

18.8

Spike
rate(%)

95.8

95.7

97.1

85.8

95.3

95.2

Grains131.2
per spike

142.4

138.7

193.0

202.4

201.7

10

Emptyhusks
rate(%)
Spike
length(cm)

4.7

11.8

9.3

23.8

21.5

24.4

21.4

21.9

22.3

26.2

27.3

26.8

1000-seed
22.2
weight (g)

23.0

22.6

22.3

22.1

22.3

Yield
6697.2(kg/hm2)

7585

7477.98243.4

9530

11072.9(2) Forecast and mitigation techniques to high temperature damage to rice,wheat and corn in China.
This task is funded by the MOA, the research period is from Jan. 2012 to Dec. 2015.
the purposes are: to identify the high temperature tolerance species of three crops,
totally, 1000 species will be identified, of which, 350 species of rice, 430 species ofwheat and 220 species of corn; and to set up a warning system of heat wave for winterwheat and of high temperature for rice and corn.

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