from a supply perspective there is concern about the slowing down of yield growth in staple crops to levels that are insufficient for meeting future food demands without the expansion of agricultural land which is already scarce in asia some studies predict that in south asia the climate change scenario would result in a percent decline in rice production relative to the noclimatechange scenario a percent decline in wheat production and a percent fall in maize production nelson etal a percent increase in the global population by will require a percent increase in food production taking into account changing consumption patterns