Climate Change: Impact on Agriculture and Food Security in an Uncertain Future Alex De Pinto...

Climate Change: Impact on Agriculture and Food Security in an

Uncertain FutureAlex De Pinto

Research Fellow

Environment and Production Technology Division

International Food Policy Research Institute2010 CAADP AFRICA FORUM, October 2010

Food Security Challenges are Unprecedented

Population growth• 50 percent more people by 2050• Almost all in developing countries

Income growth in developing countries• More demand for high valued food (meat, fruits,

vegetables) Climate change – exacerbates existing threats,

generates new ones

UNDERSTANDING CLIMATE CHANGE AND FUTURE SCENARIO BUILDING

Rising average temperatures historically

Source: http://data.giss.nasa.gov/gistemp/graphs/

IPCC Special report on Emissions Scenarios:

Population and GDP Growth Assumptions A1The A1 scenarios are of a more integrated world. Characterized by: Rapid economic growth. A global

population that reaches 9 billion in 2050 and then gradually declines. The quick spread of new and efficient technologies. A convergent world - income and way of life converge between regions. Extensive social and cultural interactions worldwide.

A2The A2 scenarios are of a more divided world. A world of independently operating, self-reliant nations.

Continuously increasing population. Regionally oriented economic development. Slower and more fragmented technological changes and improvements to per capita income.

B1The B1 scenarios are of a world more integrated, and more ecologically friendly. Rapid economic growth as

in A1, but with rapid changes towards a service and information economy. Population rising to 9 billion in 2050 and then declining as in A1. Reductions in material intensity and the introduction of clean and resource efficient technologies. An emphasis on global solutions to economic, social and environmental stability.

B2The B2 scenarios are of a world more divided, but more ecologically friendly. The B2 scenarios are

characterized by: Continuously increasing population, but at a slower rate than in A2. Emphasis on local rather than global solutions to economic, social and environmental stability. Intermediate levels of economic development. Less rapid and more fragmented technological change than in A1 and B1.

.

Current CO2 emissions are higher than most scenarios

Source: (Manning et al., 2010)

The Role of General Circulation Models (GCMs)

GCMs are mathematical models of the general circulation of a planetary atmosphere

Applied for weather forecasting, understanding the climate, and projecting climate change

Temperature could increase much more

Source: Figure 10.4 in Meehl, et al. (2007)

Change in average annual precipitation, 2000-2050, CSIRO GCM, A1B (mm)

Change in average annual precipitation, 2000-2050, MIROC GCM, A1B (mm)

CNRM A2

ECHAM5 A2

CSIRO A2

MIROC3.2 A2

How Climate Change Affects Agriculture

Lower yields for crops and livestock from• Higher temperatures• Changes in precipitation patterns • Extreme events

Sea level rise Climate change will bring location-specific changes

in precipitation, temperature and variability

There will be winners and losers!

Yield Effects, Irrigated Rice, CSIRO A1B (% change 2000 climate to 2050 climate)

Yield Effects, Irrigated Rice, MIROC A1B (% change 2000 climate to 2050 climate)

Yield Effects, Rainfed Maize, CSIRO A1B (% change 2000 climate to 2050 climate)

Yield Effects, Rainfed Maize, MIROC A1B (% change 2000 climate to 2050 climate)

Lost agricultural area from sea level rise

With 1 meter rise

(000 ha)

With 3 meter rise

(000 ha)

Myanmar 295 1,214

Thailand 199 796

Cambodia 35 118

Vietnam 2,513 4,281

30 percent of Vietnam rice growing area

Climate change reduces average yields of current varieties (percent change)

Crop/ management system

Sub-Saharan Africa

East Asia and Pacific

South Asia

Irrigated rice

NCAR -14.1 -19.8 -15.5 CSIRO -11.4 -13.0 -17.5Rainfed maize

NCAR -4.6 1.5 -7.8 CSIRO -2.4 -3.9 -2.9Rainfed wheat

NCAR -21.9 -14.8 -44.4 CSIRO -19.3 -16.1 -43.7

Sub-Saharan Africa badly affected

CHARACTERIZING PLAUSIBLE FUTURES

Overall (Economic and Demographic) Scenarios under Varying Climate Futures

Overall Scenarios:Population and GDP Growth Assumptions

Baseline – Medium GDP and medium population growth

Optimistic – High GDP and low population growth Pessimistic – Low GDP and high population growth

Global and Regional GDP per capita growth scenarios

pessimistic baseline optimisticCentral Africa 2.42 3.92 4.85Western Africa 2.04 3.63 4.03Eastern Africa 2.72 4.18 4.97Northern Africa 1.78 2.60 3.49Southern Africa 0.55 2.98 3.44

Population GDP GDP per capita

Pessimistic 1.04 1.91 0.86Baseline 0.70 3.21 2.49Optimistic 0.35 3.58 3.22

Global growth rate assumptions, annual average 2010-2050 (%)

African income per capita growth rate assumptions, annual average 2010-2050 (%)

Climate Scenarios

Climate scientists “All scenarios have equal probability.”

Our modeling approach• For each overall scenario, use 2 GCMs and two SRES

scenarios, chosen for wide range of global average precipitation outcomes

• GCMs – MIROC (Japanese) and CSIRO (Australian)• SRES scenarios – A1B and B1• Data from 4th IPCC assessment

IMPACTS: FOOD SUPPLY AND DEMAND, TRADE, FOOD

SECURITY

Biophysical effects from crop and hydrology models and

economic effects from global partial equilibrium agriculture model

Global Change Model Components

GCM climate scenarios Assumptions of Pop. And GDP growth DSSAT crop modeling system

• Biophysical crop response to temp and precipitation at 5 arc minute resolution (10 km pixels at equator)

IFPRI Spatial Allocation Model - SPAM • Spatial distribution of crops based on crop calendars,

soil characteristics, climate of 20 most important crops IMPACT

• Global food supply demand trade model. Results to 2050 with global hydrology and crop model results

Climate Change Makes Food Price Increases Greater

Rice Wheat Maize Soybeans -

50

100

150

200

250

300

350

400

450

2000 2050 No climate change 2050 CSIRO NoCF 2050 NCAR NoCF

Do

llar

s P

er M

etri

c T

on

Prices increase without climate change

2050 MIROC NoCF

Greater price increases with climate change

Mean Price Increases, Overall Scenarios (2000$/mt)

Mean baseline price increase – 57%

Preliminary results

Mean Price Increases, Overall Scenarios (2000$/mt)


Preliminary results

Mean Price Increases 2010-2050, Overall Scenarios (2000$/mt)


Preliminary results

Developed Country, Change in Net Exports of Cereals, 2000-2050 (million mt)

With perfect mitigation, DC net cereal exports grow.

With climate change, DC net cereal exports grow less or decline.

Preliminary results

Comparing the Effects of Climate Change to Economic Development

Optimistic scenario Pessimistic scenario

Perfect mitigation

(Ave. Kcals/day) (Ave. Kcals/day)

Developed countries

All developing countries

Low income developing countries

Preliminary results

CLIMATE CHANGE ADAPTATION COSTS

Our Definition of Agricultural Adaptation

Agricultural investments that reduce child malnutrition with climate change to the level with no climate change

What types of investments are considered?• Public sector agricultural research• Irrigation expansion and efficiency improvements• Rural roads

Adaptation Costs are over $7 billion per Year

Required additional annual expenditure in developing countries

“Wetter” NCAR scenario = US$7.1 billion “Drier” CSIRO scenario = US$7.3 billion

• Research - $1.3 billion• Irrigation - $3.0 billion• Rural roads - $3.0 billion

Regional Results

Sub-Saharan Africa - $3 billion (40% of the total), mainly for rural roads

South Asia - US$1.5 billion, research and irrigation efficiency

Latin America and Caribbean - US$1.2 billion per year, research

East Asia and the Pacific - $1 billion per year, research and irrigation efficiency

Adaptation Strategies

Good development policies and programs are good adaptation practices

Revitalize national research and extension systems Invest in

• Rural roads• Irrigation area and efficiency

Global data collection and information sharing

Agriculture can play a role in mitigating climate change

Modifying and introducing agricultural practices so that:• Sequester CO2 from atmosphere and store it soils

• Reduce GHG emissions Receive payments for this environmental service

Conclusions

Food security challenges from income and population growth are serious.

Climate change worsens the food security challenge regardless of realized climate

Strong economic growth is critical for food security and resilience to climate change

International trade flows help compensate for differing productivity effects of climate change

It is critical to start now to address the challenges!

www.ifpri.org

Thank you/Merci beaucoup

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