Climate Change: Impacts on Crop Production and the Environment

Bano MehdiDepartment of Geography

McGill University

McGill Conference on Global Food SecurityOctober 5-7, 2009, McGill University

Session on : Climate Change and Food Security

IntroductionClimate will become more variable, and will changeParticularly the climate parameters of

TemperaturePrecipitation

How will this affect agricultural crop production?What are the ramifications on the environment?

What does this mean for land use change?What are the consequences for water quality?

Introduction Temperature Precipitation Environment Conclusion

Temperature predictions:Multi model averages and assessed ranges for surface warming

IPCC 2007: WG1-AR4

Best estimate

Introduction Temperature Precipitation Environment Conclusion

Temperature change and crop production1. Longer growing season length2. Increases in crop damage & yield reductions3. Adjusting production patterns4. Interactions among crops, weeds, insects, and disease

Introduction Temperature Precipitation Environment Conclusion

Global impacts of climate change on agriculture

IPCC 2007: WG2-AR4

Mid to high-latitude crops benefit from a small warming (~+2oC) but plant health

declines with additional warming

Longer growing season: land use changeOpportunities may arise for farmersNorthward extension of crop lands and grazing zones Drivers for change

Longer growing seasonHigher GDDSubsidies (biofuels)Land more valuableAccess to marketsAccess to knowledge

???

Introduction Temperature Precipitation Environment Conclusion

Precipitation predictions:Projected patterns of global precipitation changes (scenario A1B)

IPCC 2007: WG1-AR4

Winter Summer

Introduction Temperature Precipitation Environment Conclusion

Impacts of precipitation changesVariable precipitation patterns

Less reliableFrequency of extreme eventsIntensity increases

Impacts on soil erosion

SWCS 2003

Introduction Temperature Precipitation Environment Conclusion

Erosion rates•15 and 30 min rainfall intensities have increased by 10%. Greatest for the 2 and 5 yr return periods.•For a 10% increase in mean annual ppt, change in erosion by 24% and change in runoff by 25%.

Water quality implicationsIntense events will contribute to higher erosionSurface runoff likely to increaseLand use will affect the severity of water quality degradation

???IWRM and BMPs are tools to help relive the burden of ag areas contributing to pollution, and can assist with water management plans

(A. Jamieson)

(C. Pertchy)

Introduction Temperature Precipitation Environment Conclusion

Other global change impacts on crop production

Population changeDemands

Energy changesBiofuel crops

Economic changeMarket factors

…

Introduction Temperature Precipitation Environment Conclusion

EC 2008

In Closing:Climate change impacts on crop production

Temperature increasesLonger growing seasonFrost incidences

Precipitation variationsMore intense events

Elevated CO2

Resulting non-climatic factors impacting the environmentWaterNutrientsErosion Pests …

Introduction Temperature Precipitation Environment Conclusion

Thank you