Also evident (and frustrating) in the report is the fact that we are entering a brand new territory and we have no previous history of such an event to estimate how it will affect agriculture locally or globally. Some crops will obviously move northward, but what will replace them in the southern regions? With a growing season 20-40 days longer, will we be able to grow two main crops in one season? Will there be enough water to grow these crops? And so many questions that do not have full answers.
The USDA report is 186 pages long but 40 of these pages are the hundreds of papers and references compiled into the report. It should be mandatory reading to all farmers, even non-American ones. By the way, some of the graphs in it show for instance that the number of farms and acreage has been stable for 20 years (last decade data not available yet), another reason to fill in that farm survey every 5 years (and the deadline has just been extended too).
The USDA published a similar report on climate change and forestry, and dozens of outlets reported on both. The impact on forestry will probably be more important, as agriculture is artificial, mostly annual for crops and mostly controlled by man, while we don't have much control over the Rockies or Appalachian forests.
The sad thing is that many climate change denialists will ignore this report. In Iowa for instance, only 10% of the farmers believe that climate change is caused by man, so there is a strong sociological barrier before accepting the situation.
Together with the reports, the USDA published an adaptation plan on how to beat this climate change; The plan is publicly open for review until April 8.
Won't be long before we grow prickly pears and raise African cattle...