Iowa in a Changing Climate

Guest Essay by Cornelia F. Mutel
October, 2018

It’s increasingly difficult to ignore. Iowa’s climate is changing, and major environmental challenges are sweeping across our state. Gentle rains are giving way to downpours that dump 4, 5, 6 or more inches of water in a few hours. Rains cut deep erosion channels into wooded land and fields and flood nearby river bottoms. Seasons are becoming jumbled, with winters shrinking, winter days rising to near-summertime temperatures, and springs that might sport winter-like snowstorms but more commonly fade too fast into summer’s prolonged heat waves. Nature is reflecting this seasonal mixup: chorus frogs sing spring mating songs in November, and violets and spring-beauty wildflowers may bloom in the darkness of December. Year after year, month after month, weather records are being broken.

Iowa’s “normal” climate seems to be dissolving in increasingly commonplace flash floods. Weather today feels less predictable, less dependable and nurturing. But can this really be true? Weather is, after all, marked by its variability. Could the current rash of extreme weather events really be signs of larger climate trends? Might we humans be altering nature’s most basic underlying processes? Could our burning of fossil fuels (coal, oil and natural gas), which increases atmospheric carbon dioxide that traps the sun’s radiant heat, be the cause of dramatic new weather extremes?

Scientists have discussed this probability for nearly 200 years. In 1824, physicist Joseph Fourier wrote that burning fossil fuels could, with time, increase Earth’s temperature. Within 40 years, a suite of heat-trapping gases had been identified, the major contributor being carbon dioxide. Systematic weather measurements began in the 1870s, and by the 1950s, scientific instruments were documenting the long-predicted steady increase in atmospheric carbon dioxide.

Today precise measurements clearly trace the accelerating increase of both atmospheric carbon dioxide and the Earth’s average temperature – which from 1901 to 2016 rose nearly 1.8°F (1°C). Most of that increase has occurred since 1980. Now, virtually all climate scientists worldwide link increases in carbon dioxide to rises in temperature and trace both back to human activities, primarily our use of fossil fuels.

A few degrees more warmth doesn’t sound like much. And yet this tiny average heat boost is affecting weather events around the world. To understand how, consider Iowa’s temperature, which in 2017 had risen around 1°F, half the global average but enough to produce significant weather changes.1

Iowa’s small warming has formed an unhealthy partnership with atmospheric moisture and extreme weather. Warmer temperatures increase evaporation from our lakes, rivers, and soils. And warmer skies hold more moisture than cooler skies. It’s not surprising that Iowa monitoring stations have recorded an increase of 2-4 percent absolute humidity per decade since 1971. The greatest rises are occurring in spring in eastern Iowa. Between 1970 and 2017, Dubuque measured an amazing 23 percent increase in absolute humidity.

More humidity, in turn, leads to greater rainfall: Iowa’s annual precipitation has increased from 31-32 inches in early 1900 to 36 inches today.

Heat is energy. Rising temperatures mean more atmospheric energy, which creates more intense and extreme weather. Between 1958 and 2012, very heavy precipitation events increased 37 percent in the Upper Midwest.2

Steadily climbing heat, moisture and energy are the Midwestern climate-change indicators being generated by our daily activities. The majority of carbon dioxide released to the atmosphere in the last century originated in the U.S. Iowa’s per-capita greenhouse gas emissions exceed the national per-person average, mainly because of agriculture, which accounts for a third of the state’s emissions.3

Looking beyond the Midwest, we see climate change composing a different message. In the Arctic, where temperatures are warming 2 to 3 times faster than the global average, ancient polar ice melts into the sea as Greenland sheds its miles-thick glaciers. As dissolving ice and warming waters swell the planet’s oceans, higher tides regularly surge into East Coast cities, flooding streets and buildings. Major storms, fueled by the warmer oceanic waters, slam one coastline after another, touting unbelievable rainfalls and winds.4 In contrast, western states dry out as they heat up. The result: more droughts that kindle larger and longer wildfires. Add in other changes around the globe, and one can see that climate change is now affecting everyone and everything, from food production to infrastructure to water quality, biodiversity and human health

These changes circle back to touch lives here in the Heartland. We inhale the hazy smoke blown in from western wildfires. Arctic warming alters high-altitude circumpolar winds, a process thought to stall air masses and prolong heat waves and cold spells here in Iowa. And what might happen in coming decades, if global sea levels (predicted to rise 3 feet or more by 2100) start pushing east-coast residents westward? Might pressures for living space here escalate – even as demands for Iowa-grown food soar?

Intensifying weather extremes are already multiplying hardship and destruction, degrading natural systems, and stressing our nation’s budget. In 2017, U.S. extreme weather events cost $306.2 billion, the highest annual cost on record. Since 1980, damages from extreme weather have exceeded $1.5 trillion.5

In 2018, a major new scientific report laid out in clear terms the risks we now face.6 If we continue down our current fossil-fuel path, the global average temperature rise will increase 50 percent to 2.7°F sometime between 2030 and 2052. That rise will steadily magnify today’s extreme heat, rain, wind and drought, along with their spinoffs: wildfire, flooding, sea level rise, loss of ice sheets and coral reefs, spread of disease, species migration and die-off, and crop failure until thresholds are crossed and Earth’s governing processes spin beyond our control. The report states that to counteract tipping points, we must rapidly replace fossil fuels with renewable energy sources that do not emit carbon dioxide, such as wind, solar and biofuels. We need to lower these emissions globally to near net-zero by 2050. Doing so will require far-reaching changes in energy sources, agricultural systems and consumption patterns.

And yet, even with these dire predictions, the intensity of future climate change still depends on the carbon dioxide we emit in coming months and years. At this time, we possess the technology and capacity to limit climate change’s most far-reaching effect. Options focus on speeding the switch to from fossil fuels to renewable energy. Iowa is already embracing this effort: wind energy has provided 8,000 to 9,000 jobs in 2017, solar another 800-plus jobs through its 52 Iowa companies in 2018.7

Elsewhere, Canada, Australia, China, many European nations, and others are moving toward placing a fee on carbon emissions. Many see a global carbon fee as a crucially important. Other efforts include plans to ban fossil fuel cars in Norway, Britain and China, while 19 nations and 32 cities around the globe are committing to net-zero emissions by 2050 through joining the Carbon Neutrality Coalition.8 These are only a few of the current proactive national and international policies and activities now underway.

Closer to home, Iowa City adopted a Climate Action and Adaptation Plan in September 2018. The comprehensive plan embraces multiple actions, from transportation and building efficiency to lifestyle sustainability, and reducing municipal, residential, and business greenhouse-gas emissions 80 percent or more by 2050.9 And MidAmerican Energy plans to generate enough renewable energy by 2021 to meet 100 percent of its Iowa customers’ energy needs each year.10

Individuals are also discovering ways to reduce their carbon footprint: driving less in more fuel-efficient (or electric) cars; flying less; changing their eating habits; making homes and workplaces more energy-efficient; downsizing, etc. And they are voting accordingly, advocating and encouraging the businesses, state and local governments, churches, and other entities that are actively addressing climate change. They are finding that addressing climate change can provide multiple benefits that improve both the quality of life and the environment.

Additional Resources:

  • Center for Global and Regional Environmental Research, at the University of Iowa website This website contains climate change information and links to other information sources, including the annual Iowa Climate Statements prepared by Iowa scientists for the general public.
  • City of Iowa City, Climate Action and Adaptation Plan, adopted 9/2018, 85 pp. 
  • Hawken, Paul (Ed.), 2017, Drawdown: The Most Comprehensive Plan Ever Proposed to Reverse Global Warming, Penguin Books, N.Y. 240 pp. Multi-authored, highly acclaimed compendium of numerous ways to combat climate change, accessible and readily usable by the lay public.
  • Henson, Robert, 2014, The Thinking Person’s Guide to Climate Change, American Meteorological Society, Boston MA. 516pp. A clear and comprehensive guide to climate change science written for a lay audience; highly recommended and regularly updated.
  • Iowa Climate Change Impacts Committee, January 1, 2011, Climate Change Impacts on Iowa 2010, Report to the Governor and Iowa General Assembly. This report, which summarizes how climate change was affecting Iowa around 2010, is posted at multiple locations on the web.
  • Iowa Climatology Bureau, Dr. Justin Glisan - State Climatologist (515-281-8981), Iowa Dept. of Agriculture and Land Stewardship, Wallace State Office Building, Des Moines, IA. Monthly and annual climate and weather reviews and other reports, contact for Iowa information.
  • Iowa Dept. of Agriculture and Land Stewardship, Climatology Bureau, and NOAA, National Centers for Environmental Information, Climate at a Glance Statewide Mapping. Iowa digital weather data and weather maps to summarize the current state of Iowa’s climate.
  • Intergovernmental Panel on Climate Change (IPCC) and its reports: the world’s preeminent international body, established in 1988 by the United Nations, for assessing the science related to climate change. This body of climate scientists from around the world regularly prepares reports for policy makers on the science, impacts, future risks and options for climate change.
  • Midwestern Regional Climate Center, 2204 Griffith Dr, Champaign, IL. Climate and weather information for Iowa and the broader Midwest.
  • Mutel, C.F., 2016, A Sugar Creek Chronicle: Observing Climate Change from a Midwestern Woodland,University of Iowa Press, Iowa City IA. 240 pp. Gentle, easily read introduction to climate change interwoven in an Iowa nature journal, accessible to all audiences.
  • NOAA National Centers for Environmental Information, “Billion-Dollar Weather and Climate Disasters.” This website traces the rising number and costs of U.S. extreme climate events:
  • U.S. Global Change Research Program. 2014. Third National Climate Assessment, Washington, D.C. Periodic summaries of the effects of climate change in the U.S., now and in the future, prepared by 13 federal agencies every several years.


  1. Iowa-specific climate statistics, here and in the next 2 paragraphs, from Dr. Justin Glisan, State Climatologist, IDALS Climatology Bureau, Des Moines IA, 10/22/2018
  2. “Observed Change in Very Heavy Precipitation,” in Key Message 6: Heavy Downpours Increasing. 2014 National Climate Assessment, U.S. Global Change Research Program, Washington, D.C.
  3. Page 7: Iowa Dept. of Natural Resources. December 2017. 2016 Iowa Statewide Greenhouse Gas Emissions Inventory Report. Iowa Dept. of Natural Resources, Des Moines IA. 17 pp.Page 6: Strait R, Mullen M, Wei D, et al. October 2008. Final Iowa Greenhouse Gas Inventory and Reference Case Projections 1990-2025. Center for Climate Strategies, for Iowa Dept. of Natural Resources, Des Moines IA. 19pp plus appendices.
  4. Torrential rainfall, 49.69 inches in 24 hours, Kauai, Hawaii, April 15 2018, Hurricane Michael, maximum sustained winds of 155 mph on landfall near Mexico Beach, Florida panhandle, October 10 2018,
  5. 2017 U.S. Billion-Dollar Weather and Climate Disasters: A Historic Year in Context. Adam B. Smith, January 8 2018, U.S. National Oceanic and Atmospheric Administration.
  6. Intergovernmental Panel on Climate Change (IPCC), October 2018, Global Warming of 1.5°C.
  7. Wind Energy: Jobs & Economic Benefits in All 50 States, American Wind Energy Association website, accessed 5/12/2018. Fact sheet for Solar Energy Industries Association website, accessed 10/23/2018.
  8. “19 Countries Team Up to go Carbon Neutral,” Climate Home News Ltd., 9/28/2018
  9. City of Iowa City, Climate Action and Adaptation Plan, adopted 9/2018, 85 pp.
  10. MidAmerican Energy media relations team,, email received 10/31/2018
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