This chart shows crop yields in Illinois and Indiana compared to maximum temperature between 1980 and 2007.
Different crops respond differently to temperature increases. The following chart assumes that adequate water supply and soil moisture will be maintained - a precarious assumption as we'll see in the next few charts.
Dry spells are on the rise - This map shows the predicted increase in the maximum number of consecutive dry days, comparing the 1971-2000 period to projections for 2070-90.
Heavy downpours are washing huge amounts of top soil away. Known as "gully erosion," this kind of soil loss currently isn't counted in the US Department of Agriculture's rosy erosion numbers, which hold that Iowa's soils are holding steady. But Richard Cruse, an agronomist and the director of Iowa State University's Iowa Water Center, has found Iowa's soils are currently disappearing at a rate as much as 16 times faster than the natural regeneration. According to the National Assessment, days of heavy rain have increased steadily in Iowa over the past two decades, and will continue doing so.