Climate Change and Agriculture

Cynthia Rosenzweig

NASA/Goddard Institute for Space Studies

Congressional Briefing on

Climate Change and Agriculture: Food and Farming in a Changing Climate

June 16, 2010

Agriculture Contributes to Climate Change

Observed increase in methane is

due to anthropogenic activities,

predominantly rice production and

ruminants.

More than a third of all nitrous oxide

emissions are agricultural, primarily

due to fertilizer.

Primary source of increased carbon

dioxide is fossil fuel use, with land-

use change providing a significant

contribution.

Observed warming is just a small fraction of what is projected

IPCC 2007

The 100 year

linear trend

(1906-2005) in

temperature is

0.74 oC

0.6 oC

1.8 oC

2.8 oC

3.4 oC

Continued Greenhouse Gas Emissions Would Cause Further Warming

6.0 oC

Figure SPM-6

Updated:

PLENARY

Warming is Expected to be Greatest over Land and at Most High Northern Latitudes.

Figure SPM-6

Updated:

PLENARY

Warming is Expected to be Greatest over Land and at Most High Northern Latitudes. Hot Extremes and Heat Waves will Continue to Become More Frequent

Figure SPM-7

Updated:

PLENARY

Increases in Precipitation are Very Likely in the High-Latitudes, while Decreases are Likely in Most Subtropical

Land Regions

2090s

Figure SPM-7

Updated:

PLENARY

Increases in Precipitation are Very Likely in the High-Latitudes, while Decreases are Likely in Most Subtropical

Land Regions

Heavy Precipitation Events will Continue to Become More Frequent

2090s

Increasing

Droughts

and Floods

0

20

40

60

80

100

1990 2000 2010 2020 2040 2040 2050

Year

Pe

rce

nta

ge

R eliab ility

D em and m et

400

300

200

100

50O N D

Months

J F M A M J J A S

Runoff

(cfs

) CurrentGFDLMPIHC

Changes in

Seasonality

Water Resources are Key

Strzepek et al., 1999

Competing Demands

Domestic Users

Ecosystem Services

Excess Soil Moisture

Number of events causing damage to maize yields due to excess soil moisture

conditions, averaged over all study sites, under current baseline (1951–1998) and

climate change conditions. Events causing a 20% simulated yield damage are

comparable to the 1993 US Midwest floods (Rosenzweig 2001).

YieldsOver the last 50 years:

• Very likely

– less frequent cold days, cold

nights, and frosts

– more frequent hot days and hot

nights

• Likely

– more frequent heat waves

– more frequent heavy

precipitation events

– increased incidence of extreme

high sea level

– increased drought in some

regions

Climate Change is Already OccurringObserved impacts on Agriculture

Phenology

Management

practices,

pests and

diseases

Livestock

1973-2002 Annual temperature trends

<-1.2C to >1.2C

IPCC, 2007

Phenology

Management

practices,

pests and

diseases

Yields

Livestock

Rosenzweig et al.,

IPCC WGII Chapter 1, 2007

Climate Change is Already Affecting Agriculture

Seasonal-to-interannual – e.g., El Nino*

Decadal-to-century**

Feb1998

Feb 2000

ENSO Uruguay

Baethgen, 2000

Risk of Current Climate Extremes is

a Pathway to Climate Change

NOAA AVHRR

*Focus on Extreme events

Regional StakeholdersShort-term Decisions

Adaptation

**Focus on Mean changes

National PolicymakersGlobal Agreements,

Adaptation & Mitigation,World Food System

Ing. Juan Notaro, Uruguayan Minister of Agriculture in 1999/2000

"... The results of your work during the recent drought were useful for making

both operational and political decisions.”

The Agricultural Modeling Intercomparison and

Improvement Project (AgMIP)

• Provides global context to regional climate change

impacts on agricultural systems

• Assesses uncertainties and adaptation strategies

Climate Scenarios

Crop Models

Food Trade Models

Historical Observations,

CMIP5 and Earth

System Models

Major Crop Modeling

Groups, Regional

Agricultural Experts

Major Economic

Modeling Groups

Online Project

Guidance, Archive,

and Clearinghouse

Intercomparisons

Crop Models

Food Trade Models

Gauge Uncertainties

Adaptation Capacity Building

Adaptation and Mitigation

Regional Crop Assessments

Trade Policy Instruments

Technological Exchange

Extended Applications

Water Resources

Pests and Diseases

Livestock and Pastures

Vulnerability