Around 1,000 years ago, Native Americans in the Midwest built large settlements, like Cahokia near St. Louis and Angel Mounds in southwest Indiana.
Indiana University-Purdue University Indianapolis scientist Broxton Bird says the growth came with warmer, wetter weather.
“And it’s at that point that they adopted corn and their populations expanded,” Bird says.
Fast forward 500 years and the researchers found a colder, drier climate. That’s bad for corn, says Jeremy Wilson, another IUPUI scientist who co-led the study.
“So with resource short falls, you know, it leads to social unrest,” says Wilson.
The researchers created a new climate record from about 900 to 1500 by studying layers of sediment in Martin Lake in northwest Indiana. Those layers told the researchers about temperature and rainfall patterns. They then compared that data with records showing when those communities started eating corn and the size of the settlements.
Broxton Bird says, today, climate change and a warming world could mean a wetter Midwest, which could be good for agriculture.