Impacts of Warmer, Wetter Climate Outlined
Published: Friday, January 31, 2025
Michigan farmers were advised by the state's top climate expert last week to watch for extreme and erratic rainfall events, higher temperatures and longer growing seasons with less water. Speaking at a farm meeting in Southwest Michigan, State Climatologist Jeff Andresen offered a weather update last Tuesday in Three Rivers in a pre-recorded presentation during the On-Farm Soybean Research Update at GreenMark Equipment.
"The single most important point here, in Michigan, the Great Lakes region and the Midwest, is that we're on a warmer and wetter trajectory," Andresen said as he introduced historical, current and projected trends in crop climates.
He said the impacts of this for farmers include: higher yields, longer growing seasons with increased temperatures, opportunities to plant alternative varieties of crops, increased flash flood and flash drought risk, and increases in weed, pest and disease pressure.
In terms of precipitation, Andresen said the Midwest, particularly Michigan, gets about 14-18 inches of rain in a season. In contrast, a corn crop needs an average of 20-25 inches of rain, leaving about a 5–10-inch deficit.
"The rest comes out of the soil," he said.
However, the climate is trending wetter, he said.
Precipitation events in the past few decades have become heavier, with 4 inches of rain or more in one shower, with these numbers increasing. Andresen expects heavier instances of rain in the future with more time in between, resulting in flash floods and droughts.
According to the data, "high severity floods occur every two to seven years," Andresen said. And this is increasing across the Midwest.
"Since the beginning of last century, the climate has warmed up. It's been by about 2 degrees Fahrenheit, a little warmer than that. But, a very important point, it wasn't all uniform, and it didn't all happen at once."
He showed data depicting a rise in temperatures from the 1920s and '30s, followed by about five years of cooling by about degree and then warming again beginning in the 1980s, which brought temperatures up 2 degrees.
"The important thing is that this is a significant change in a relatively short time frame," he said, comparing the single-century warming with thousands of years of historical data.
Last year was the warmest on record in Michigan and also nationwide, with a year-long average of 48.9 degrees.
• Some key factors of this Andresen discussed include:
• Warming does not happen all at the same time of the year,
• The greatest warming trends occur in the winter,
• More changes happen at night, and
• Rising temperatures happen more quickly at night than in the day.
He noted that the past four decades of data have been collected from satellites.
Andresen also discussed the increase in lake effect snow events in the past several years, noting that he expects an increase of these as time goes by. He explained that because the lakes are no longer freezing over completely, moisture is being released into the atmosphere over them, creating snow showers.
"This has supercharged the lake effect," he said. "But, even in areas of seasonal snowfall, snow is melting more quickly."
Andresen also noted that the national plant hardiness zones have shifted since they were originally posted in 1990, with an overall higher survival rate of overwinter vegetation.
The first and last freezing temperatures of the year have reportedly changed over the years, resulting in about three extra weeks in the growing season, according to Andresen. He said there is about a week and a half on either side of the growing season with temperatures too warm for frost.
"Maximum temperatures haven't changed much at all and have even cooled some in Michigan and Indiana and the Midwest, but minimum temperatures have been on a warming trend prominently for the past 50 years," he said.
Finally, because of warmer temperatures, Andresen said more water can be held in the atmosphere for longer, causing some challenges for farmers.
"Our rates of potential water transpiration will increase, so we'll need more water to grow crops than we have in the past," Andresen said. "(Farmers) are going to need to do more with less water."
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