Iowa scientists: Spring floods, summer droughts more likely with global climate change

Source: by Tony Leys, Des Moines Register • Posted: Wednesday, October 23, 2013

Gene Takle, director of Iowa State University's climate science program, speaks about the dangers of global climate change as other Iowa scientists listen. (Tony Leys/The Register)

Gene Takle, director of Iowa State University’s climate science program, speaks about the dangers of global climate change as other Iowa scientists listen. (Tony Leys/The Register)

Global climate change means Iowans can expect more years like 2013, when spring deluges gave way to summer drought, Iowa scientists said today.

Such patterns won’t happen every year, the scientists said, but they are becoming more frequent and fit the predictions of climate-change models.

Gene Takle, director of Iowa State University’s climate science program, said too many Americans believe there is serious dispute among scientists about whether climate change is real and whether it is caused by people. “In the scientific community, we have debates on the details,” he said. “But there are very, very few scientists who are active in studying climate science who deny the existence of the role of heat-trapping gases in raising our global average temperatures, and the fact that these heat-trapping gases are produced by humans.”

Takle spoke at a press conference at Drake University, where an annual statement by Iowa scientists was released on the likely effects of climate change.

When such a statement was first released in 2011, 44 Iowa scientists signed on, said David Courard-Hauri, chairman of Drake’s environmental science and policy program. Last year’s statement was signed by 137 Iowa scientists, he said, and this year’s was signed by 155 from 36 colleges and universities.

Courard-Hauri said the point is to demonstrate to Iowans that nearly all serious scientists agree the trend is real and dangerous. The scientists must counter arguments put forth on the internet and in the popular media that there is no solid evidence the Earth is warming. The subject is complicated and hard to explain, he said, but critics make it sound simple.

“It’s easy to set up a straw-man argument, to say, ‘Oh, well climates always change, there have been changes in the past. This might just be natural,’” Courard-Hauri said. “And often that gets played on the Internet as, ‘Maybe scientists haven’t thought about the fact that there have been natural changes in the past and maybe this is related.’” Of course scientists have thought about that possibility, he said, but the evidence strongly suggests the climate is changing faster than could be expected to happen naturally.

Takle said it’s true that over the past decade, the global-warming trend appears to have hit a pause. But he said that could be due to a temporary shift in ocean currents, and is not likely to be permanent. Data clearly show a dramatic warming of the earth over the past 40 years, he said, and the pause has not dissuaded many scientists from believing the overall theory.

The consensus statement released today focuses on the effects of climate change on agriculture. Takle said some effects could be positive, such as the lengthening of the growing season. But he said farmers need to take steps to prevent losses from other effects, such as the serious soil erosion caused when spring downpours hit land not covered by grasses or other plants. He also said warm nights tend to stress livestock, reducing their weight gain.

Courard-Hauri said he hopes the list of scientists will be used as a resource for Iowans who want a local expert to speak to their groups about the issue.