United States
Environmental Protection
Agency
United States
^•*5#PrjhA Environmental Protection
|L_ | f mAgency
What Climate Change
Means for
August 2016
EPA 430-F-16-024
V
Michigan's climate is changing. Most of the state has
warmed two to three degrees (F) in the last century.
Heavy rainstorms are becoming more frequent, and
ice cover on the Great Lakes is forming later or melting
sooner. In the coming decades, the state will have
more extremely hot days, which may harm public
health in urban areas and corn harvests in rural areas.
Our climate is changing because the earth is warming.
People have increased the amount of carbon dioxide
in the air by 40 percent since the late 1700s. Other
heat-trapping greenhouse gases are also increasing.
These gases have warmed the surface and lower
atmosphere of our planet about one degree during the
last 50 years. Evaporation increases as the atmo-
sphere warms, which increases humidity, average
rainfall, and the frequency of heavy rainstorms in
many places—but contributes to drought in others.
Greenhouse gases are also changing the world's
oceans and ice cover. Carbon dioxide reacts with
water to form carbonic acid, so the oceans are
becoming more acidic. The surface of the ocean has
also warmed about one degree during the last
80 years. Although warmer temperatures cause sea
level to rise, the impact on water levels in the Great
Lakes is not yet known. Warmer air also melts ice and
snow earlier in spring.
Temperature change (°F):
-1 -0.5 0 0.5 1 1.5 2 2.5 3 B.5
Rising temperatures in the last century Northern Michigan
has warmed more than southern Michigan. Source: EPA,
Climate Change Indicators in the United States.
Heavy Precipitation and Flooding
Changing the climate is likely to increase the frequency of floods in
Michigan. Over the last half century, average annual precipitation in
most of the Midwest has increased by 5 to 10 percent. But rainfall
during the four wettest days of the year has increased about 35
percent. During the next century, spring rainfall and annual precipitation
are likely to increase, and severe rainstorms are likely to intensify. Each
of these factors will tend to further increase the risk of flooding.
Heavy rains and snowmelt flooded the Tittabawassee River in Midland in April
2015. Credit: City of Midland.
Great Lakes
Changing the climate is likely to harm water quality in Lake Erie and
Lake Michigan. Warmer water tends to cause more algal blooms,
which can be unsightly, harm fish, and degrade water quality. During
August 2014, an algal bloom in Lake Erie prompted the Monroe County
Health Department to advise residents in four townships to avoid using
tap water for cooking and drinking. Severe storms increase the amount
of pollutants that run off from land to water, so the risk of algal blooms
will be greater if storms become more severe. Severe rainstorms can
also cause sewers to overflow into lakes and rivers, which can threaten
beach safety and drinking water supplies. For example, heavy rains in
August 2014 led to nearly 10 billion gallons of sewer overflows in
southeastern Michigan, much of which ended up in Lake St. Clair and
eventually Lake Erie. More severe rainstorms could also cause sewers
in Milwaukee and Chicago to overflow into Lake Michigan more often,
which could pollute beaches in Michigan.
One advantage of climate change is that warmer winters reduce the
number of days that ice prevents navigation. Between 1994 and 2011,
the decline in ice cover lengthened the shipping season on the Great
Lakes by eight days. The lakes are likely to warm another 3° to 7°F in
the next 70 years, which will further extend the shipping season.
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Ice forming on Lake Michigan near St. Joseph. Credit: M. McCoimick,
NOAA Great Lakes Environmental Research Laboratoiy.
Winter Recreation
Warmer winters are likely to shorten the season for recreational
activities like ice fishing, snowmobiling, snowboarding, and
skiing, which could harm the local economies that depend on
them. Small lakes are freezing later and thawing earlier than a
century ago, which shortens the season for ice fishing and ice
skating. Since the early 1970s, winter ice coverage in the Great
Lakes has decreased by 63 percent. Warmer temperatures are
likely to shorten the season when the ground is covered by
snow, and thereby shorten the season for activities that take
place on snow. Nevertheless, annual snowfall has increased in
much of the Great Lakes region, which could benefit winter
recreation at certain times and locations.
Ecosystems
The ranges of plants and animals are likely to as the climate
changes. For example, warmer weather could change the
composition of Michigan's forests. As the climate warms, the
population of paper birch, quaking aspen, balsam fir, and black
spruce may decline in the Upper Peninsula and northern Lower
Peninsula, while oak, hickory, and pine trees may become more
numerous. Climate change will also transform fish habitat.
Rising water temperatures will increase the available habitat for
warmwater fish such as bass, while shrinking the available
habitat for coidwater fish such as trout. Declining ice cover and
increasingly severe storms would harm both types of fish
habitat through erosion and flooding.
Warming could also harm ecosystems by changing the timing of
natural processes such as migration, reproduction, and flower
blooming. Migratory birds are arriving in the Midwest earlier
in spring today than 40 years ago. Along with range shifts,
changes in timing can disrupt the intricate web of relationships
between animals and their food sources and between plants and
pollinators. Because not all species adjust to climate change in
the same way, the food that one species eats may no longer be
available when that species needs it (for example, when migrat-
ing birds arrive). Some types of animals may no longer be able to
find enough food.
Agriculture
Changing the climate will have both beneficial and harmful
effects on farming. Higher concentrations of atmospheric carbon
dioxide and longer frost-free growing seasons would increase
yields of wheat during an average year. But increasingly hot
summers are likely to reduce yields of corn and possibly
soybeans. Seventy years from now, Michigan's Lower Peninsula
is likely to have 5 to 15 more days per year with temperatures
above 95°F than it has today. More severe droughts or floods
would also hurt crop yields.
Air Pollution and Human Health
Changing the climate can harm air quality and amplify existing
threats to human health. Higher temperatures increase the
formation of ground-level ozone, a pollutant that causes lung and
heart problems. Ozone also harms plants. In some rural parts of
Michigan, ozone levels are high enough to significantly reduce
yields of soybeans and winter wheat. EPA and the Michigan
Department of Environmental Quality have been working to
reduce ozone concentrations. As the climate changes, continued
progress toward clean air will become more difficult.
Hot days can be unhealthy—even dangerous. High temperatures
can cause heat stroke and dehydration, and affect people's
cardiovascular and nervous systems. Northern cities iike Detroit
are vulnerable to heat waves, because many houses and
apartments lack air conditioning, and urban areas are typically
warmer than their rural surroundings. In recent decades, severe
heat waves have killed hundreds of people across the Midwest.
Heat stress is expected to increase as climate change brings
hotter summer temperatures and more humidity. Certain people
are especially vulnerable, including children, the elderly, the sick,
and the poor.
The sources of information about climate and the impacts of climate change In this publication are: the national climate assessments by the U.S. Global Change Research
Program, synthesis and assessment products by the U.S. Climate Change Science Program, assessment reports by the intergovernmental Panel on Climate Change, and
EPA's Climate Change Indicators in the United States. Mention of a particular season, location, species, or any other aspect of an impact does not imply anything about
the likelihood or importance of aspects that are not mentioned. For more information about climate change science, impacts, responses, and what you can do, visit EPA's
Climate Change website atwww.epa.gov/climatechanae.

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