Can China Continue Feeding Itself? The Impact of Climate Change on Agriculture, Water

Scarcity and How Farmers Adapt

Jinxia WangCenter for Chinese Agricultural Policy (CCAP)

Chinese Academy of Sciences (CAS)

Co-authors: Robert Mendelsohn, Ariel Dinar, Jikun Huang,

Scott Rozelle and Lijuan Zhang

Food Security in China

• Policy debate: Global food security issues

-- Especially in China

-- Many studies focus on such issues

-- Most research results in China are positive

However, All these studies do not consider climate change

Global Climate Change

• Scientific evidence shows: Rising greenhouse gases planet

warming

Important to understand the impacts of

global warming

• Impacts to agriculture

Largest and best documented impacts

Impacts of Climate Change on Agriculture

• Agronomic studies (In China and other developing countries): Climate change reduces crop yield (-) Assume the same crops in the same place Without considering farmers’ adaptations

• Economic studies based on Ricardian model (Africa, South

America, Brazil, India, …): Climate change reduces farmer revenue Except in cool locations and some places with irrigation (Egypt)

Considering farmers’ adaptations

• So, considering the adaptations, what will happen to China when climate changes?

Research Questions

• What are the impacts of climate change

on agriculture (net crop revenue)?

• How do farmers adapt to climate change

(irrigation or crop choice)?

Presentation

• Methodology/Data

• Results of the impacts of climate change

on crop net revenue

• Results of the impacts of climate change

on irrigation and crop choice

• Conclusions and project justification

Economic Approach: Ricardian Model

• Regress net revenues (or land values) on climate, soil, characteristics of village and household

• Include climate by season in quadratic (second order approximation) form

• Examine all farms, rainfed and irrigated farms.

Data…• Climate data: - Source: National Meteorological Information Center

- Monthly temperature and precipitation from meteorological 733 stations - 1951~2001 - Divide into four seasons: Spring: 3~5; Summer: 6~8 Fall: 9~11; Winter: 12~2 - Calculate the average annual temp. and prec. for each season using data from 1951~2001

Data…• Socio-economic Data

-- Source: China’s National Bureau of Statistics

Nation-wide Household Income and Expenditure Survey

-- Sample:

Counties having both meteorological stations and HH 8405 HH in 915 villages, 124 counties and 28 provinces

Data…• Socio-economic Data

-- Net crop revenue by HH: Gross crop revenue (or total sales for each crop) less than

All expenditures for production (seed, fertilize, irrigation, pesticide, machinery, plastic sheeting, hired labor and custom services, not including land rent and family labor)

Return to land and family labor

-- Household and village characteristics Education level of household members Family’s land area Topographical environment of each village (plain or mountain) Irrigation status (share of irrigated areas) Easy to access to market (road, distance to township government)

Data

• Soil Data -- FAO

-- Clay, sand and loam soils

-- Share of cultivated areas with each

type of soil at county level

Average Annual Marginal Impacts of Climate Change on Net Crop Revenue in China

All farmIrrigated

farmRainfed

farm

Temperature -10 68 -95

Precipitation 15 27 23

Changes of net revenue due to minor change of climate(USD/ha)

Minor increase of temperature will reduce the net revenue of all farms, especially for rainfed farms; however, minor increase of precipitation will increase the net revenue of all farms

Marginal Temperature Effect, Irrigated Farms

Warmer temperature are more beneficial in the Southeast and southwest region. Farms in the Central region enjoys mild benefits from warming, however, the far north will be damaged by warming

Marginal Precipitation Effect, Irrigated Farms

Almost all Irrigated farms enjoy small benefits from increased rainfall

Marginal Temperature Effect, Rainfed Farms

Warming is likely helpful to rainfed farmers in very cold places but it will likely harm rainfed farmers in most of China and especially the far south

Marginal Precipitation Effect, Rainfed Farms

More rain is likely to be harmful to rainfed farmers in the wet southeast but will benefit farmers in the remaining regions

Summary: Impacts of Climate Change on Net Crop Revenue in China

• The average impact of higher temperature is negative and the average impact of more precipitation is positive;

• However, effects will vary by region;• Rainfed farmers are more vulnerable than

irrigated farmers;

• Irrigated farmers are less sensitive to temperature and gain from increased rainfall.

Advantage of Economic Approach and Its Limitation

• Advantage of the Economic Approach (Ricardian model)

-- It provides an estimate of the benefits derived from adaptation -- After considering adaptations, farmers’ losses from warming will be greatly reduced and even slightly gain especially for irrigated farms -- The results of crop model can be treated as without adaptation

• Limitation on the data -- Do not know how much water farmers used in irrigation, cannot

quantify the effect of water in the economic model

-- If climate change does reduce water supplies, there will be harmful impacts on agriculture

Trend of Discharges at Aixinzhuang Station ： Lower Haihe River Basin

Serious Dry-up Issues in the Downstream of the Yellow River

Increase of Groundwater Irrigation in Northern China

Percent of groundwater irrigated area

Hebei: Falling Shallow GW Table

Hebei: Falling Deep GW Table (1980-98)County

Meter/year

Changes of Water Uses in China

China is facing a water crisis

• At least that is the perception of some scholars and policy makers inside and outside of China

– Senior agricultural and water policy officials claim that water shortages pose the largest challenge to China’s agricultural sector in the 21st century

– Some researchers say it will seriously disrupt food production in China

Shanxi

HenanShaanxi

Hebei

Inner Mongolia

Liaoning

Data set 1:

2004 North China Water Resource Survey (NCWRS):

6 provinces, 50 counties, 400 villages

Data set 2:

2001/2004 China Water Institutions and Management (CWIM) Panel

2 provinces, 9 counties, 48 villages

(village leaders, groundwater managers, surface water managers, & farm households)

Groundwater Levels are Falling, but Varies across Northern China

Change in Average Water Level 1995-2004

（ 1995-2004 ）• Increased : 16%• No Change: 18%• Decreased < 0.25 m/year ： 17%

• Decreasing 0.25 to 1.5 m/year : 40%• Decreasing > 1.5 m/year : 8%

52%

52%

Our findings on water scarcity and government and farmers’ response…

• There is a water scarcity… but, the scarcity is not everywhere! There are many parts of China in which water resources have not deteriorated over time …

• 1/2 of North China is suffering from rapidly falling groundwater tables

• Facing with a water crisis, the government has begun to made a number of institutional and policy responses (such as issuing regulations, reforming irrigation management and establishing water rights), not very effective.

• In the future, water crisis will continue to grow especially as competition among users increase and even more so, if there is not an effective implementation of policies

Our findings on water scarcity and government and farmers’ response…

• Where water is becoming scarce, producers, community leaders are responding

Digging tubewells by individuals Developing groundwater market Reducing water use and changing cropping patterns when water price increases Adopting water saving technologies However, faced with water scarcity, some responses are

helping, some are hurtingHence, Government cannot ignore response of farmers,

in fact they need to use this responsiveness to reduce adverse effects and encourage conservation

When Climate Changes, How Farmers Make Response?

• How will changes of temperature and precipitation influence irrigation choice?

• How will changes of temperature and precipitation influence crop choice?

Annual Marginal Effect of Climate Change on Irrigation Choice in China

Sign of Marginal Effect

Temperature _

Precipitation _

Increasing temperature and precipitation will promote farmers to switch from irrigated agri. to rainfed agri., Chinese farmers are more likely to irrigate when facing lower temperatures and less precipitation

Annual Marginal Effect of Climate Change on Crop Choice in China

Temperature Precipitation

Wheat + -

Maize + -

Rice - +

Cotton + +

Oil + +

Potato - -

Soybean - +

Sugar - +

Vegetable - +

Summary: Adaptation Results

• As temperatures warm, move away from cool loving crops towards heat tolerant crops

• As precipitation falls, move away from wet loving crops towards drought tolerant crops

Conclusions …• Different from pessimistic results of the crop studies,

economic results show that the impact of climate change on agriculture are smaller;

• The major reason is that economic method implicitly captures the adaptations, such as crop switching, changes in irrigation and other changes that farmers might undertake;

• The mildly harmful marginal effect of higher temperature is mainly due to two reasons:

-- Large irrigated areas -- Rainfed land in temperate or cool regions• So, irrigation is critical to China’s agriculture system; • If warming forces many irrigated farms to become

rainfed farm, the positive results will be reversed

Conclusions

• The effect of climate change varies by region• It is very important to explore regional adaptation

measures (such as water policies) that fit the conditions in each region, rather than uniform national policies

• The ability of Chinese farmers to adapt to climate change is very important, government should support adaptation at large

So, it is very important to implement adaptation project on climate change!