What’s Climate Change Doing in Iowa?
Connie Mutel
Connie Mutel
NB: This version of this article is found in the Summer 2018 issue of Conservation Connection: the Johnson County Conservation Newsletter.It is used with Connie’s permission. A similar but shorter version ran in the Gazette, July 8, 2018.
This past spring, during yet another April snowstorm, you likely heard, “Climate change? Global warming? Who says the planet is warming? If it is, bring on the heat!”
Although I’ve known about climate change for many years, it’s taken me a while to understand what it means to Iowa and to our planet. What I’ve discovered is profound. The most obvious global change? A rise of 1.8° F (1° C) in average surface air temperature between 1901 and 2016, with the greatest increase occurring since 1980. That number is the average of thousands of measurements, both high and low, taken every day and night, on land and sea, from the poles to the equator.
Virtually all trained scientists agree that this rise in temperature is caused primarily by the release of carbon dioxide and other greenhouse gases from the burning of fossil fuels. Climate scientists also agree that today’s seemingly small rise in average temperature is already affecting weather events around the globe. However, our planet is not warming uniformly. Thus, while the Arctic’s temperature is rising at twice the global average, Iowa has warmed only half of the global amount: about 1° F. Most of Iowa’s warming is occurring during winter and at night, mercifully excluding more extreme summertime highs, at least for now.
One degree. Not much, you might say, but this statewide-average rise is already affecting Iowa’s environment. Higher temperatures naturally increase water’s evaporation from our lakes, rivers, and soils. And warmer skies can hold more moisture than cooler skies. Thus Iowans might expect increases in atmospheric humidity.
And sure enough, monitoring stations across the state have recorded an increase of 2 to 4% in absolute humidity per decade since 1971, with the greatest rises in the eastern half of Iowa. Increases are largest in the springtime months of April, May, and June. During these months, between 1970 and 2017, Dubuque measured an amazing 23% increase in absolute humidity.
In tandem, Iowa’s annual precipitation has gone up about 5 inches, from a statewide average of 31 or 32 inches at the beginning of the 20th century to around 36 inches today. Most of that increase has occurred since 2000, and (like absolute humidity) the increased rainfall is concentrated in the spring months of April, May, and June.
But remember that heat is a form of energy. Thus it’s no surprise that our hotter, moister skies are producing more intense extreme weather events. The 2014 Third National Climate Assessment concluded that in the Upper Midwest, very heavy precipitation increased 37% between 1958 and 2012. I remember well the April afternoon five years back when I returned to our woodland home near Iowa City after a localized but intense rainfall. The entire broad valley below our house was flooded to a depth of 6 to 8 inches. Gushing water cut into the valley floor, eating away large chunks of soil that collapsed into the deepening streambed. Everywhere rivulets poured off hillsides, creating new streamlets where none had existed before. Many spring wildflowers clung tenuously to the soil with a single meager rootlet.
This unprecedented 7-inch rainfall redefined the hydrology of our woodland and initiated major erosion. Yet today a 7-inch rain no longer seems unusual. Around the world, intense rainfalls of 12, 14, 16 inches and more are no longer uncommon. Last year Hurricane Harvey dumped an unbelievable 50 inches on parts of Houston over 7 days, and in mid-April this year a 49-inch rain in Hawaii set a U.S. record for the amount of rainfall in a single day. In Iowa, flood risks are rising.
Intense rains and other extreme weather events are stressing economic as well as natural systems. The U.S.’s extreme weather events cost $306.2 billion in 2017, the highest annual cost on record. Since 1980, damages of such increasingly frequent events in the U.S. have exceeded $1.5 trillion. Add other factors to these stresses—such as climate-related health problems, agricultural upsets, infrastructure failures, and ecosystem shifts—and you will see that climate change touches everything.
The connections between heat, rain, and extreme storms make sense. But what about this past spring? What explains the snowstorms and frigid temperatures? Of course, even as temperatures rise, we will continue to have cold weather, just increasingly less of it. But climate scientists are relating this past spring’s weather to climate change by examining the polar vortex, the rapidly spinning low-pressure area at the North Pole that historically has trapped and held cold air in the Arctic. This past February, while still in the clutches of 24-hour darkness, the Arctic warmed an unprecedented 45° F above the norm, which weakened the polar vortex and allowed frigid air to gush southward into the U.S. The plume of Arctic air was held in place for weeks by a persistent area of high pressure over Greenland.
With all the recent cold weather, spring has been slow to arrive. Even as I write, in late April, the first wildflowers in our woods are barely starting to unfurl. And chorus frogs, which should be shouting their mating songs from every ephemeral pond, are trilling but a few tentative chirrups. In coming weeks I expect their songs and the wildflowers to increase. But everything seems less predictable, less dependable now than in the past. I think of what could happen if we do not rapidly and dramatically reduce our greenhouse gas emissions. The prediction, for example, that by 2050, if we do not address climate change, Iowa’s greatest summertime once-per-decade heat waves will be 13° F hotter than today’s. How will we survive this, I wonder? By 2100, if we continue with business as usual, our global average temperature will have increased by 7 to 9° F, making today’s 1.8° F rise seem like child’s play.
What can we do? Let’s start by recognizing that the science of climate change is accepted by virtually all trained climate scientists. Then let’s act accordingly on all levels, focusing on speeding the switch to renewable energy sources that can power our world without multiplying climate change. Yes, this means changes in policies and regulations—just as other nations are invoking. China, now the poster child for manufacturing and installing solar arrays, is working toward banning the manufacture and sale of fossil fuel cars, as are Britain and Norway. Costa Rica was almost totally powered by renewable energy in 2017, and New Zealand has committed to carbon neutrality by 2021, with other nations joining the lineup. Here in America, we need to talk about climate change more, vote accordingly, advocate strongly, and praise the businesses, state and local governments, churches, and other entities that are lowering their greenhouse gas emissions.
Each of our personal actions can also play a role. A family’s choices can make a difference. Find out how much by going on the web and measuring your carbon footprint. Then figure out what you can do. Eat less meat? Drive less in a more fuel-efficient car? Fly less? Add more insulation to your home? Go for it!
We are now in a race between rising fossil fuel emissions and efforts to reduce these emissions and moderate their spinoffs. The switch to renewable energy is happening, even as global temperatures continue to rise. The benefits of renewables are many: cleaner air and water, improved human and environmental health, economic stimulation and more jobs, a better-functioning and more intact natural world. Which forces will win the race? We don’t know. But we do know this: All people on the planet at this crucial time will own the results, whether they lead to a globe that repels life and beauty and culture, or to a healthier, self-renewing, more stable planet fueled by the sun, wind, and other renewables. The choice remains ours.
Thanks to Professor Gene Tackle, Director of the ISU Climate Science Program, and to Harry Hillaker, Iowa’s former State Climatologist, for statistics on temperature, humidity, and precipitation changes in Iowa. Statistics on the cost of extreme weather events and on Hurricane Harvey are from the U.S. National Oceanic and Atmospheric Administration, “2017 U.S. Billion Dollar Weather and Climate Disasters: A Historic Year in Context (January 8, 2018).”
Connie Mutel, IIHR-Hydroscience & Engineering at the University of Iowa, is author of several books on Iowa’s natural features, including A Sugar Creek Chronicle: Observing Climate Change from a Midwestern Woodland (2016).
Connie Mutel, with IIHR-Hydroscience and Engineering at the University of Iowa, is author of several books on nature in Iowa including A Sugar Creek Chronicle: Observing Climate Change from a Midwestern Woodland (2016) and editor of the 2010 “Climate Change Impacts on Iowa” report prepared for the Iowa Legislature and governor.
Connie is a former board member of the Friends of Johnson County Conservation and presently serving on the Johnson County Conservation Board.