Summaries of Observations
Articles
Warming Hurts African Crops, Interacts with Rain 0311
Coffee Yields Plummet As Climate Warms 0311
Warmer Weather Drives Crops Northward 1010
Rice Yield Growth Rates Falling as World Warms 0810
Rice Response to Warm Nights - Welch 0810 - PDF
Even Slow Warming Could Halve Crop Yields 0909
Crops Fall w Slow Warm, Supplement - Schlenker 0909 - PDF
Rice re CO2, O3, Temp - Ainsworth 0308 - PDF
Rice Yields Fall 10+% per 1°C Night Warming - Peng 0704 - PDF
17% Fall in Corn & Soybean Yields per 1°C Warming in US - Lobell 0203 - PDF
Climate Impacts on Agriculture - Hatfield 0411 - PDF, 20 pp. This literature review is the basis of the Agriculture chapter in the draft US National Climate Assessment.
This leads to the graphical interpretation, based primarily on Grain Yield. The vintages of studies vary, so doubled atmospheric CO2 levels varied accordingly. The graph adjusts for vintage.
This leads to this graphical interpretation. Important caveats have to do with other limiting factors besides temperature - notably nitrogen and water, but also phosphorus, potassium, weeds, insects, soil carbon and acidity, etc.
Yield responses, based on June temperatures (generally in the middle of the growing season) are shown for cities in the middle of the primary growing areas.
Yields are sensitive to temperatures (and many other factors) in several months, not just June, as different events occur during the growing season. But June temperatures are at least indicative. Corresponding graphs for southern hemisphere growers (notably Brazil, Argentina, and Australia) would use December temperatures.
Winter and spring wheat are both economically important in the US, India, China, etc. An adaptation to warming already well under way is to plant winter wheat in Pakistan and northern India. But even winter in Delhi is warm (mean temperature 60-65°F, much warmer than San Diego or San Antonio).
This slide summarizes conclusions by Welch (here), Ainsworth, Peng, and Lobell (all below), and others.
The following can also be said, based on these and other studies.
Summary of Schlenker & Roberts' work.
Section Map: Food Impacts