Drought and climate change

The empirical analysis on climate change shows a shift in the temperature distribution that suggests that there is a greater likelihood of a temperature  spike in the most recent decade. (We are not arguing the overall cause, but note that the shift will increase the chance of a weather shock on Midwest crops.) If the shift in distribution is more permanent, then the likelihood that these temperature extremes become recurring events increases. 

The impact on food is direct because temperature and drought effect yields. We are at the outer limits for the amount of acreage that can be planted so marginal changes in supply will be associated with yield which is directly effected by the weather

Information:  James Hansen, Makiki Sato, and Reto Ruedy “Perception of Change” Proceedings of the National Academy of Sciences August 6, 2012. 

The distribution figures show a clear shift in the data. The heat maps on a global basis show there are more temperature anomalies.