This article, by Jerry Schnoor, also appeared in the January 17, 2011 edition of the Daily Iowan.
By Jerry Schnoor
How much has the climate changed in Iowa over recent decades? What are the impacts on the State’s agriculture, water resources, wildlife, public health and the economy? These questions served as the impetus for a new report released this month, requested by the Iowa Legislature, and produced by a small group of faculty and staff working together from the regents’ institutions in Iowa.
Gene Takle, a professor of atmospheric science at Iowa State University, analyzed the primary data and found that today’s Iowans are experiencing a wetter, milder climate. We are living with more temperate winters, a longer growing season, warmer summer nights, increased humidity, greater precipitation (especially in April-July), and more intense rainfall events.
No one knows if the 2008 flooding was caused by climate change. Because of the nature of statistics, we cannot attribute any single event to climatic shifts. But we do know that extreme events will likely become more frequent as a result of our changing climate. We continue to emit greenhouse gases into the atmosphere at record rates, where they accumulate, warming the atmosphere and the oceans, melting ice, and changing climate patterns across the globe.
Here in Iowa, we have meteorological records going back more than a century, and we can glean some information from those data.
One hundred years ago, it was rare to receive rainfall greater than 4 inches in a single day, but it has occurred several times in recent years. Such events caused the floods in Iowa in 1993, 2008, and 2010. We can no longer say that these are “100-year” or “500-year” events.
Accordingly, we must adapt to these disasters by “hardening” our infrastructure for water and wastewater plants, power facilities, transportation systems, and roads and bridges. We should protect our water quality and soil by preventing erosion, preserving marginal lands and restoring wetlands and prairies.
We shouldn’t allow new development in the floodplain. Existing floodplain structures should be designed to be flooded — that is, adapted for easy cleaning and reuse after floodwaters enter the building.
Not everything about Iowa’s changing climate is bad. Our report shows that farmers are benefiting from longer growing seasons — yields are higher because of plentiful moisture and, for soybeans, a higher concentration of carbon dioxide in the atmosphere. Iowans are saving on heating bills in the winter. Flowers are blooming earlier, and our new climate conditions are conducive to warm-weather varieties.
However, other effects are not so pleasant. Disease vectors and insects can survive the warmer winters. Greater moisture in the air has increased pollen and mold spores, exacerbating allergic responses and asthma. Flooding, too, can increase the incidence of respiratory ailments through the propagation of mold.
Overall, the economic impacts of climate change in Iowa so far have been mixed, but the likelihood of future flood damages looms large. Our prominent insurance industry is already responding to climatic shifts by handling more claims, and developing new risk-reducing products and services.
Iowans are already responding to climate change, whether they realize it or not. The trick for the future will be to adapt wisely. If we want to reverse the tide of global climate change, the whole world (including Iowa) must eventually tackle the difficult question of reducing greenhouse-gas emissions through greater energy efficiency and renewable energy sources.
Jerry Schnoor, a professor of civil & environmental engineering at the University of Iowa, is the co-director of the Center for Global and Regional Environmental Research, and a member of the Iowa Climate Change Advisory Group and author of its report to the Governor.