NCA4: American Heartland Fact Sheet


The National Climate Assessment finds that global warming is impacting every state in the country, and those in America’s Heartland are no different. The Midwest and Great Plains are seeing hotter temperatures, more intense downpours, flooding, crop damages and other impacts that are all expected to get stronger if climate change continues unchecked.

Here is a sample of some of the findings of the Midwest and Northern and Southern Great Plains chapters of the NCA.

Warming is here, and we’re feeling its impacts:

  • The frost-free season has increased in the Midwest by an average of nine days since 1901.
  • In the Midwest, rising humidity and warming winters have made it possible for existing pests, like the invasive emerald ash borer or mountain pine beetle to survive longer, and are allowing new pests to travel northward, threatening plants and trees.
  • Climate change is affecting the Great Lakes, which provide drinking water for 35 million people, through decreasing ice cover, increasing water temperatures, and increased evaporation, which can lower water levels and disrupt lake ecosystems and food webs.
  • The Midwest has already experienced a rise in pollen production, as pollen season begins sooner and extends further, posing a particular threat to children with asthma and others.
  • Climate change is already exacerbating the limited water availability, like in 2003 when Standing Rock Reservation ran completely out of water during a drought.
  • Warming will bring an additional month or two of stiflingly hot summer temperatures in the Southern Great Plains: we can expect an additional 30-60 days a year above 100F, a doubling, by late 21st century.
  • Temperatures in the Southern Great Plains are projected to increase by up to 5.1F by 2050, and up to 8.4F by late 21st century.
  • The Karner blue butterfly appears to have gone extinct at the southern end of its range in Indiana because of climate change.
  • Plant species in Wisconsin forests have already moved north about 30 miles since the 1950s, tracking with climate conditions for now, though they will likely be unable to do so as warming accelerates.

Extreme precipitation and flooding is already here, but will grow worse:

  • Heavy precipitation events like the ones in May 2017 that flooded over 400 state roads in Missouri have become more intense and more frequent since 1901, and will increase through the next century. The cost of upgrading storm water systems to handle increases from climate change could climb over $480 million per year by the end of the century under high and low emission scenarios.
  • Spring rainfall has increased in the Midwest in the last 30 years, providing soil moisture but also increasing erosion and increasing the risk of mold, fungus and toxins.
  • Overall, Midwest precipitation has increased as much as 15% over the 1901-1960 average, and will increase up to 30% more by the end of the century.
  • A 100-year flood of the 20th century in the Cedar River basin in Iowa will be a 25-year flood of the 21st century. The increased spring rains and flooding of agricultural lands will likely worsen fungus and disease outbreaks, including plant diseases like bacterial spot in pumpkins.
  • The number of heavy precipitation events are projected to increase significantly for much of the northern great plains, but in the mountains of western Wyoming and western Montana, the amount of water in precipitation that falls as snow instead of rain is expected to decline by 25%-40% by 2100.
  • In 2017, Hurricane Harvey broke U.S. rainfall records, and was the latest in a string of record-breaking flooding in Houston, which experienced similar events in 2015 and 2016.

Climate Change is Already Threatening Americans’ Health, And Will Get Worse:

  • Tropical, vector-borne diseases have recently begun appearing in southern Texas, like Zika, Chikungunya and Dengue.
  • Hotter temperatures are linked to deaths in the Midwest, as well as diseases like dehydration and heat stroke. The Midwest is projected to have the largest increase in heat-related premature deaths by the end of the century – an additional 2,000 deaths per year in the high emission scenario.
  • When Texas experienced a summer 5.2°F higher than average, there was a measurable increase in emergency room visits (3.6%) and even deaths (0.6% increase.)
  • The Midwest region is expected to see an additional 200 to 550 premature deaths per year due to increased ozone levels by 2050, in addition to overall worsened health conditions
  • The Midwest has experienced increased pollen production and related allergies in recent years. Oak pollen is projected to be responsible for an increase of 88 to 350 emergency room visits for asthma by 2050.

The Economic Impacts of Climate Change Are Big, And Growing:

  • The Midwest has seen three billion-dollar floods in the last 25 years, and projections indicate that increased flood risk from warming will cause an excess of $500 million by 2050. Additionally, climate change will increase bridge maintenance costs by $400 million dollars a year by 2050, and is expected to increase road maintenance costs by $6 billion annually by 2090.
  • Commodity crops will be hurt by climate change, with an expected decline of as much as 25% for corn and over that for soybeans in the southern half of the Midwest.
  • Additional premature deaths in the Midwest from increased ozone levels are estimated to cost $4.7 billion
  • Local economies that depend on winter or river-based recreational activities are suffering from shorter snow seasons, lower summer streamflows, and higher stream temperatures.
  • Higher temperatures in the Northern Great Plains are expected to increase demands for electricity, which will increase costs to the power system of about $13–$18 million per year by 2050 and $42–$80 million per year by 2090 in a high emission scenario.
  • In 2016, proliferative kidney disease killed thousands of native mountain whitefish in Montana, which triggered a month-long closure of 180 miles of the Yellowstone River to all water-based recreation. Initial estimates of the economic impact to local communities range from $360,000-$524,000.