As agriculture intensified in the 20th century, summers in the Midwest became wetter and cooler. An MIT study published this month looked at whether vegetation from crop production, rather than greenhouse gas emissions that are an established source of climate changes, could have driven these regional impacts.

“We provided very strong evidence that agricultural intensification is a stronger forcing of these observed changes than greenhouse gas emissions were,” says lead author Ross Alter, who conducted the research as a postdoctoral associate at MIT and is now a research meteorologist with the U.S. Army Corps of Engineers in New Hampshire.

Alter says more crops equals more photosynthesis and more water used by plants. All of that contributes to increased rainfall and humidity and cooler temperatures because of increased evaporation — rainfall consumes so much sunlight (solar energy), there isn't enough left to raise the air temperature.

“This study suggests that there’s evidence that, yeah, we ought to be considering agricultural impacts" when using models to predict how the climate may continue changing, says Iowa State University agronomist Rick Cruse.

Read the full article about intensive agriculture causing climate change by Amy Mayer at Harvest Public Media.