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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
Page 2
UNDERSTANDING CLIMATE CHANGE AND FUTURE SCENARIO BUILDING
Page 3
Rising average temperatures historically
Page 4Source: 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.
.
Page 5
Current CO2 emissions are higher than most scenarios
Page 6Source: (Manning et al., 2010)
The Role of General Circulation Models (GCMs)
Page 7
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
Page 8Source: Figure 10.4 in Meehl, et al. (2007)
Change in average annual precipitation, 2000-2050, CSIRO GCM, A1B (mm)
Page 9
Change in average annual precipitation, 2000-2050, MIROC GCM, A1B (mm)
Page 10
Page 11
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!
Page 12
Yield Effects, Irrigated Rice, CSIRO A1B (% change 2000 climate to 2050 climate)
Page 13
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)
Page 16
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
Page 18
Sub-Saharan Africa badly affected
CHARACTERIZING PLAUSIBLE FUTURES
Overall (Economic and Demographic) Scenarios under Varying Climate Futures
Page 19
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
Page 20
Global and Regional GDP per capita growth scenarios
Page 21
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
Page 22
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
Page 25
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$/mt)
Page 26
Mean baseline price increase – 57%
Preliminary results
Mean Price Increases, Overall Scenarios (2000$/mt)
Page 27
Mean baseline price increase – 106%
Preliminary results
Mean Price Increases 2010-2050, Overall Scenarios (2000$/mt)
Page 28
Mean baseline price increase – 67%
Preliminary results
Developed Country, Change in Net Exports of Cereals, 2000-2050 (million mt)
Page 29
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
Page 30
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
Page 32
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
Page 33
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
Page 34
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
Page 35
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!
Page 37
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Thank you/Merci beaucoup