Rebecca Hersher

The firefighters came on Monday. They went up and down the halls, knocking on every apartment in the six-story Ansonborough House building in downtown Charleston, S.C., and leaving notices on the doors of those who didn't answer: This area is under mandatory evacuation.

The manager of the building heeded the warning and left a note on the window in the lobby explaining that the building would not be staffed all week.

If you want to know what climate change will look like, you need to know what Earth's climate looked like in the past — what air temperatures were like, for example, and what ocean currents and sea levels were doing. You need to know what polar ice caps and glaciers were up to and, crucially, how hot the oceans were.

Humans must drastically alter food production to prevent the most catastrophic effects of global warming, according to a new report from the United Nations panel on climate change.

The panel of scientists looked at the climate change effects of agriculture, deforestation and other land use, such as harvesting peat and managing grasslands and wetlands. Together, those activities generate about a third of human greenhouse gas emissions, including more than 40% of methane.

It technically began last fall when Hurricane Florence swelled the Ohio River, but really it was all the unnamed storms that came after it — one after another after another, bringing rain on rain on rain across the central U.S. until the Mississippi River hit flood stage this winter.

Much of the Mississippi, and the massive tributaries that feed it, stayed flooded until June. That meant more than 140 days of cascading disasters for hundreds of small towns from Minnesota to Louisiana and catastrophic damage to ranch and farm communities that dot the Mississippi's swollen branches.