AMES, Iowa - Iowans are seeing increases in precipitation and temperature, a longer and warmer growing season, better conditions for the survival and spread of agricultural pests and the economic consequences of a changing climate, according to a report authored by researchers at Iowa's three regent universities.
"Climate change is already affecting the way Iowans live and work," says the study by the Iowa Climate Change Impacts Committee. "Without action to mitigate these affects, our future responses will become more complex and costly."
Legislation approved in April 2009 asked the committee to study the effects of climate change on Iowa. That study was conducted by representatives of Iowa State University, the University of Iowa and the University of Northern Iowa and coordinated by the Iowa Office of Energy Independence. The study was sent to Gov. Chet Culver and the Iowa General Assembly on Monday. The full report is here.
Iowa State University contributors to the report were Gene Takle, a professor of geological and atmospheric sciences and agronomy who directs the university's Climate Science Program; Richard Cruse, a professor of agronomy; Dave Swenson, an associate scientist in economics; and Natalia Rogovska, a post-doctoral research associate in agronomy.
Takle reported on climate changes in Iowa. He noted Iowa has experienced a long-term trend toward more precipitation, an increase in extreme summer rainfall, and warmer temperatures, particularly over the winter and at night.
"Current state climate changes are linked, in very complex and sometimes yet-unknown ways, to global climate change," Takle wrote in the report. "Some changes, such as the increased frequency of precipitation extremes that lead to flooding, have seriously affected the state in a negative way. Others, such as more favorable summer growing conditions, have benefitted the state's economy."
Cruse and Rogovska reported on agriculture in Iowa. They noted that some recent climate changes are good for agriculture. The longer growing season and reduced drought stress have helped to increase corn and soybean yields.
But, they wrote, higher monthly rainfall, more atmospheric moisture from crop transpiration and reductions in winds also create favorable conditions for crop pests and pathogens. An increase in the intensity and amount of rainfall is also increasing the erosion of soil in farm fields.
Swenson reported on Iowa's economy, infrastructure and emergency services. He noted that the most prominent impacts of climate change are likely to be seen in agriculture. Longer, warmer and wetter growing seasons should increase corn yields, and higher amounts of atmospheric carbon dioxide could increase soybean yields. The result should be stable or lower food and feed costs.
But, he wrote, by mid-century warmer drier conditions are expected to decrease crop yields and livestock health.
To address these and other impacts of a changing climate, the committee recommended seven policy initiatives:
● Consider the rising financial and human impacts of Iowa's recent climate trends - including more extreme rain events that can result in summer floods - in policy and appropriation decisions.
● Take strong steps to protect Iowa's soil, water quality and long-term agricultural productivity.
● Increase investments in state programs that enhance wildlife habitat and management because changes in climate will directly impact game and non-game species.
● Ask the Iowa Department of Public Health to report annually on how changing climate is affecting the health of Iowans.
● Advocate for federal highway construction standards that consider the effects of climate change and encourage the Iowa Department of Transportation to explore interim construction designs that account for trends in Iowa's climate.
● Authorize the Iowa Insurance Division to periodically issue reports and recommendations about the risks and costs of property insurance related to climate-related claims and payouts.
● Fund ongoing research of Iowa's climate and how climate changes will affect Iowa and Iowans.
"Iowans are already living with warmer winters, longer growing seasons, warmer nights, higher dew-point temperatures, increased humidity, greater annual streamflows, and more frequent severe precipitation events than were prevalent during the past 50 years," said the committee's report. "Some of the impacts of these changes could be construed as positive, and some are negative, particularly the tendency for greater precipitation events and flooding. In the near-term, we may expect these trends to continue as long as climate change is prolonged and exacerbated by increasing greenhouse gas emissions globally from the use of fossil fuels and fertilizers, the clearing of land, and agricultural and industrial emissions."