Spring rainfall will continue to be above levels Iowans have experienced in the past, said Iowa State University climate scientist Chris Anderson.
Iowans, and especially farmers and residents of flood-prone cities, “definitely need to adjust to that reality,” said Anderson, who will be the keynote speaker at a daylong Dec. 11 symposium titled “Adapting to Weather Extremes: The Economic Impact in Iowa.”
Since the record floods of 2008, Iowa has been besieged by extreme weather, as exemplified by this year’s rapid swing from record spring rainfall to flash drought. Those extreme fluctuations have cost billions of dollars – an expense Iowans can reduce by adapting to changing climate patterns, according to sponsors for the symposium, which runs from 8 a.m. to 5 p.m. at Hy-Vee Hall in Des Moines.
To illustrate the increasing expense of weather-related damages, Anderson compared insurance loss payments to Iowans for two recent five-year periods.
From 2000 through 2004, insurance payments to Iowans for losses associated with tornadoes, floods and corn and soybean crop failures totaled $2.1 billion. In inflation-adjusted currency, those same categories of insurance payments, for the years 2008 through 2012, totaled $5.8 billion, he said.
Those figures do not include uninsured losses or payments from government flood recovery programs, he said.
Anderson said “forward-looking data,” which has only recently been adapted for practical predictions, indicate that generally warmer weather in Iowa is 15 to 20 years down the road. The warming trend generally associated with climate change is muted in Iowa because of the increased rainfall, he said.
“One temperature trend that is obvious,” he said, “is a higher frequency of warm nights, especially in the summer.” That has negative implications for agriculture because the elevated temperature prevents plants from resting, which reduces yields, he said.
The frequency and severity of droughts, Iowa farmers’ greatest fear, have not been affected by climate change, according to Anderson.
“Temperature patterns in the Pacific Ocean dictate the occurrence of Midwest droughts,” he said.
Iowa’s changing climate impacts agriculture more than any other segment of the state’s economy, according to ISU agronomy professor Rick Cruse, another of the speakers at the symposium.
While farmers fear drought and excessive heat more than any other extreme weather condition, Cruse said the “the greatest cost (of the changing climate) to farmers is the soil lost through erosion” during increasingly frequent heavy rainfall events.
The reduced fertility of eroded soil shrinks farmers’ yields long into the future, and the loss of organic material makes the soil less resilient to drought and extreme heat, he said.
Iowa Agriculture Secretary Bill Northey, another symposium speaker, said increased application of technological advances can help farmers cope with weather extremes.
“Large efficient equipment lets us get out there and plant crops, even when weather gives us small windows of opportunity, and improved hybrid seeds yield plants that can resist stress from heat, drought and pests,” he said.
Improved conservation practices, such as cover crops, reduced tillage, grass waterways and buffer strips, can hold soil in place and make it more resilient to extreme weather, he said.
Changing weather patterns are also affecting the state’s natural resources, according to another symposium speaker, Tim Hall, chief of the Department of Natural Resources Iowa Geological and Water Survey.
A prime example, he said, is the steep 21st century decline of what once was the state’s foremost game animal, the ring-necked pheasant.
While habitat loss has accelerated that decline, Hall said it has coincided with an unusual sequence of snowy winters and wet springs that have hurt pheasant survival and reproduction.
In three of the last four years, record low statewide pheasant populations have been documented by the annual August roadside counts.
The economic impact of pheasant hunting in Iowa has declined from $140 million per year in 1996 to $20 million in 2011, Hall said.
Frequent severe flooding during the past decade has also necessitated expensive repairs to state and county parks and destroyed important features of the natural environment, according to Hall.
Following prolonged and extensive Missouri River flooding in 2010, “nearly 100 percent mortality of mature cottonwood trees” has been documented in the floodplain, he said.
Event sponsors are the University of Iowa Public Policy Center, the University of Iowa Center for Global and Regional Environmental Research, University of Iowa Hydroscience and Engineering (IIHR), the Climate Science Program at Iowa State University and the Iowa Water Center.