Climate change stresses likely to cut agricultural output from the nation’s breadbasket
By Summit Voice
SUMMIT COUNTY — The Midwest could be among the regions hit hardest by climate change, according to a trio of University of Michigan researchers who authored sections of the recent national climate assessment.
The region is likely to face frequent and more intense heat waves, water quality degradation and public health threats, with increasing risks to Great Lakes ecosystems.
“Climate change impacts in the Midwest are expected to be as diverse as the landscape itself. Impacts are already being felt in the forests, in agriculture, in the Great Lakes and in our urban centers,” said University of Michigan aquatic ecologist Donald Scavia, director of the Graham Sustainability Institute and special counsel to the U-M president on sustainability issues.
In the Midwest, extreme rainfall events and floods have become more common over the last century, and those trends are expected to continue, causing erosion, declining water quality and negative impacts on transportation, agriculture, human health and infrastructure, according to the report, which is open for public comment.
Climate change will likely worsen a host of existing problems in the Great Lakes, including changes in the range and distribution of important commercial and recreational fish species, increases in invasive species, declining beach health, and more frequent harmful algae blooms. However, declines in ice cover on the Great Lakes may lengthen the commercial shipping season.
The rate of warming in the Midwest has accelerated over the past few decades, according to the report. Between 1900 and 2010, the average Midwest air temperature increased by more than 1 degree Fahrenheit. However, between 1950 and 2010, the average temperature increased twice as quickly, and between 1980 and 2010 it increased three times as quickly.
The warming has been more rapid at night and during the winter. The trends are consistent with the projected effects of increased concentrations of heat-trapping greenhouse gases, such as carbon dioxide released by the burning of fossil fuels.
Projections for regionally averaged temperature increases by the middle of the century, relative to 1979-2000, are approximately 3.8 degrees Fahrenheit for a scenario with substantial emissions reductions and 4.9 degrees for the current high-emissions scenario. Projections for the end of the century in the Midwest are about 5.6 degrees for the low-emissions scenario and 8.5 degrees for the high-emissions scenario, according to the report.
In agriculture, longer growing seasons and rising carbon dioxide levels are likely to increase the yields of some Midwest crops over the next few decades, according to the report, though those gains will be increasingly offset by the more frequent occurrence of heat waves, droughts and floods. In the long term, combined stresses associated with climate change are expected to decrease agricultural productivity in the Midwest.
The composition of the region’s forests is expected to change as rising temperatures drive habitats for many tree species northward. Many iconic tree species such as paper birch, quaking aspen, balsam fir and black spruce are projected to shift out of the United States into Canada.