Rows of corn wait to be harvested in a field in Minooka, Illinois, September 24, 2014. REUTERS/Jim Young

The bipartisan trio of climate risk prognosticators for the business community — Michael Bloomberg, former Treasury Secretary Hank Paulson, and billionaire investor Tom Steyer — are back. And this time, their Risky Business Project has produced a report focusing in particular on how a world of rising temperatures could threaten the Midwestern region of the U.S.: the Heartland.

Perhaps the most striking finding? A higher prevalence of extremely hot temperatures could severely impact corn and wheat production, the report warns, unless we take serious evasive action. It cites a 1 in 20 chance of an 80 percent loss for these crops by 2100 – the extreme case. The more likely range for losses, says the document, is 11 to 69 percent.

Here’s a figure from the report, whose scientific conclusions are based on research performed by a group of scientific and economic experts convened by the Rhodium Group (their more technical report is here):

Kate Gordon, lead author of the new Risky Business report, and head of the energy and climate change program at Next Generation, explains that if Midwestern agriculture sustains such losses, food production may move north. “But for those people, in those states, that’s their economy, it’s a pretty severe impact,” she says.

The new report also says the Midwest could experience more heat deaths, costlier electricity, and a decline in overall workforce productivity. It suggests, for instance, that by the end of the century, temperatures in Missouri could be a lot like they are in Arizona right now — with between 46 and 115 days above 95 degrees per year.

Similarly, it says Chicago could become a lot like today’s Texas, having even more days per year above 95 degrees than the Lone Star State currently does.

All of this depends, of course, upon which climate change scenario the world allows to develop. Slashing emissions now doesn’t ensure a cessation of all global warming, but it definitely mitigates the risk of more extreme scenarios.

Perhaps most strikingly, the report also includes a finding that by the end of the century, going outdoors could become unsafe on a few days each year, thanks to a particularly extreme combination of heat and humidity.

“Increasing heat and humidity in some parts of the region could lead to outside conditions that are literally unbearable to humans, who must maintain a skin temperature below 100°F in order to effectively cool down and avoid fatal heat stroke,” notes the document.

Midwesterners could experience as many as 3 days per year with this dangerous heat-humidity combination by century’s end, says the report. It defines such a day as a “Category IV” on a “Humid Heat Stroke Index,” noting that on such days, heat stroke would be “likely for fit individuals undertaking < 1 hour of moderate activity in the shade.”

“We’ve never had a day in the United States that hits that, but by the end of the century, you get several per year,” says lead study author Kate Gordon.

Again, it is important to underscore that this depends on a certain climate change scenario becoming reality — namely, the pretty severe scenario that would occur if we “continue on our current path,” in the study’s words.

The report is framed economically — these kinds of threats, it notes, will be very bad for business and industry — and the Midwest is not only the center of much U.S. agriculture but contains a third of its manufacturing.

“This is a way of looking at climate change that the business community understands, and a lot of conservatives really understand,” says Gordon.