Researchers Work To Track North American Climate Change

"There is no question now that the climate is changing on a global scale," says Takle, an Iowa State University professor of geological and atmospheric sciences and agronomy. "The evidence is so overwhelming."

But what does that mean on a smaller scale? How are greenhouse gases changing the climate in North America? In the United States? In Iowa? After all, "You and I are not affected by a few tenths of a degree of temperature change on a global scale," Takle said.

Takle is working with Bill Gutowski, an Iowa State professor of geological and atmospheric sciences, and Ray Arritt, an Iowa State professor of agronomy, to find some answers about regional climate change. The three have worked together on climate studies for 15 years. And now they've joined an international group of scientists collaborating on the North American Regional Climate Change Assessment Program.

The assessment program is led by Linda Mearns, a senior scientist at the National Center for Atmospheric Research in Boulder, Colo. The National Science Foundation is funding the Iowa State work on the project with a $353,000 grant. The project calls for six teams of researchers (four from the United States, including the Iowa State group, one from Canada and one from Europe) to run their own regional climate models using at least two sets of identical data from two research groups studying global climate change.

The research groups will see what their models say about regional climate change and compare the results. Ultimately, the researchers will create data sets that will help them study the impacts of climate change on a continental or even statewide scale.

Takle said the Iowa State research team has looked at Iowa climate data from 1975 to 2000 and observed some trends: Annual precipitation has increased by about an inch over the past 30 years. More of that precipitation is happening in extreme weather events. In other words, Takle said, there are more 3-inch rains than there were 30 years ago. Winter low temperatures aren't as cold. Takle said that means there are about eight more frost-free days than there were in the 1950s. That makes for a longer growing season. The summer heat isn't as intense as it was 30 years ago, but the humidity is rising. If those trends continue, Takle said climate change in the American Midwest could be good for agriculture over the next 10 to 20 years.