Global Warming

Impact on agricultureand foodsupply 169

Trace

gases Climate models

Observed

climate

Climate

change

scenarios

CO 2 effects wheat, rice, maize, soya beanCrop models adaptationsFarm-level

Crop yield by site

and scenario

evapotranspiration, irrigation,

season length

Aggregation of site results

Agroecological zone analysis

Yield functions by region

Yield = function of temperature,

precipitation and CO 2

Yield change estimates

Commodity group and

country/region

Technology

projections

Economic

growth rates

Adaptations

World food trade

model

Economic consequences

Shifts in trade

Incidence of food poverty

Population

trends

Greenhouse

policies

Sensitivity

tests

Figure 7.10Illustrating key elements of a study of crop yield and food trade under a changed climate.