Indiana is getting warmer and that trend will continue, said Jeff Dukes, the executive director of the Purdue University Climate Change Research Center. Dukes spoke Tuesday at Culver Academies as part of Green Week on campus.
The question is how much warmer and how quickly. Over the past century, the average temperature has risen by 1.2 degrees Fahrenheit, but computer models show temperatures will rise by 5-to-6 degrees by the 2050s, even with a moderate reduction of carbon dioxide in the atmosphere.
“We need to prepare for this warming now,” he explained. “It’s going to happen.”
The results are available in a recently released study, “Indiana Climate Change Impacts Assessment,” that involved more than 100 experts from more than 50 participating organizations providing input and results. The study shows two different paths based on carbon dioxide emissions, but both indicate the warming trend.
The slower trend shows the 5-to-6 degrees increase. While it does not sound like a lot, the results will be Indiana’s climate being more like western Tennessee/eastern Arkansas during the summer and Delaware and the eastern seaboard in the winter, Dukes said. By late century, the summers could resemble what is Houston now.
The study predicts a change from 20 days of 90 degrees or higher currently to 74 days in the 2050s. The high temperatures would increase from 96 in 2013 to 105 in the 2050s and 111 by the 2080s. The winters in northern Indiana go from an average low of minus 9 to minus 2. And the polar vortex experienced this past winter will become more common as the jet stream continues to move in unusual patterns.
Farmers are already experiencing some of these changes. There are fewer cold days for fruit trees to go dormant. The frost season is shorter. Precipitation is increasing by 6 to 8 percent; and that precipitation is falling as rain instead of snow. Plus 42 percent of the rain comes in downpours, which results in floods and keeps farmers out of the fields even through the growing season has actually increased by over a month. These downpours also increase pollution in rivers and streams because of the runoff.
Summer and fall are drier at the time when crops need the moisture. Summer nights are “significantly” warmer, stressing the plants and reducing yields. Corn yields have already dropped 3.1 bushels per acre per degree, he said. Soybeans are also showing a decrease.
Pest problems are also growing. Dukes said the Marion County mosquito traps have shown a steady increase in those insects in recent years.
The degree to which all this occurs will be based on the amount of carbon dioxide released in the atmosphere. Deforestation is slowing but is still a contributing factor. Use of fossil fuels has decreased but the release of carbon dioxide still went up in the last reported year after falling for several years in a row.
The good news is clean energy like solar and wind are becoming less expensive. And even the little things like switching to LED lights in homes are having an impact, he said. But the study indicates the temperatures are still going to rise.
The only question now is to what degree.