Agency	EPA 430-F-16-036
A mA United States	August 2016
f* \ jjp»% Environmental Protection
What Climate Change
Means for	Dakota
+ '
North Dakota's climate is changing. In the past
century, most of the state has warmed about two
degrees (F). Rainstorms are becoming more intense,
and annual rainfall is increasing. In the coming
decades, longer growing seasons are likely to create
opportunities for farmers, and increasing rainfall may
benefit some farms but increase the risk of flooding.
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
warmed about one degree during the last 80 years,
and sea level is rising at an increasing rate. Warming
is causing snow to melt earlier in spring.
Temperature change (°F):
-1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5
Rising temperatures in the last century. North Dakota has
warmed more than most of the United States. Source: EPA,
Climate Change Indicators in the United States.
Precipitation and Water Resources
Changing the climate is likely to increase the demand for water and
make it more available. Rising temperatures increase evaporation and
water use by plants. But rainfall is also likely to increase, so soil moisture
is likely to increase slightly or remain about the same as today. More
water is likely to run off into the upper Missouri River and its tributaries.
The resulting increase in river flows could benefit recreational boating,
public water supplies, and electric power generation. During droughts,
decreased river flows can lower the water level in lakes and reservoirs,
which may limit water supplies and impair swimming, fishing, and other
recreational activities. But if more water flows through the rivers before
or during a drought, these problems will become less likely. Higher
water flows also increase hydropower production, which accounts for
about 5 percent of all energy produced in North Dakota. Nevertheless,
droughts are likely to become more severe in downstream states. When
droughts lower water levels enough to impair navigation, the U.S. Army
Corps of Engineers releases water from the upstream dams, making
less water available to North Dakota.
Increased Flooding
Greater river flows, increasing precipitation, and more severe storms are
each likely to increase the risk of flooding. The year 2011 was one of the
wettest years on record: the Souris River near Minot crested at four feet
above its previous record, with a flow five times greater than any in the
past 30 years, and flooding occurred throughout the state. In the Red
River watershed, river flows during the worst flood of the year have been
increasing about 10 percent per decade since the 1920s.
Flooding of the Red River at Grand Forks in 1997. Flood magnitudes have
been increasing since the 1920s in the Red River watershed. Credit: Tony
Mutzenberger, USGS.

Heavy Storms
Warmer air tends to have more water vapor, so more water can
be potentially released in a storm. During the last 50 years, the
amount of rain falling during the wettest four days of the year
has increased about 15 percent in the Great Plains. Over the next
several decades, heavy downpours are likely to account for an
increasing fraction of all precipitation.
Changing the climate is likely to have both positive and negative
effects on agriculture in North Dakota. Warmer temperatures
have extended the growing season by about 30 days since
the beginning of the 20th century. Corn and soybeans are now
grown in areas that were previously too cold for those crops, and
warmer temperatures are likely to increase corn yields in the
future. The fertilizing effect of increased concentrations of carbon
dioxide is likely to further increase yields of corn and substantially
increase yields of wheat and soybeans. The extended growing
season might allow two crops per year instead of one in some
instances. Increased precipitation at the beginning of the growing
season is likely to help ensure that soils are sufficiently moist for
the growing season.
Although the longer growing season benefits most crops,
planting dates might be delayed if increased winter and spring
precipitation leaves some fields too wet to plant. Rising tem-
peratures may also reduce yields of wheat, partly offsetting the
fertilizing effect of carbon dioxide. Warmer winters may promote
the growth of weeds and pests. During drought years, hotter
summers will dry the soil more than would otherwise occur. Over
the next 70 years, the number of days above 100°F is likely to
double, which could further stress crops during drought years.
Rising carbon dioxide concentrations are likely to increase the
productivity of grasslands. Although ecosystems generally
benefit from higher productivity, several impacts of a changing
climate may harm ecosystems. Changes in temperature and
the length of the growing season may disrupt natural ecological
processes and shift species' ranges. Many species of birds are
shifting northward as temperatures rise, and warmer tempera-
tures are causing flowers in North Dakota to bloom earlier in
spring. Even small changes in the timing of plant development or
animal migration can disrupt predator-prey relationships, mating
behavior, or availability of food.
Human Health
Extremely hot and cold days can be unhealthy—even dangerous.
Certain people are especially vulnerable, including children, the
elderly, the sick, and the poor. The elderly may be particularly
prone to heat stress and other heat-related health problems,
including dehydration, cardiovascular strain, and respiratory
problems. Those with low incomes may be particularly vulnerable
due to a lack of air conditioning. Power failures due to severe
weather can also present risks, especially in lightly populated
areas where access to the necessary support services may be
limited. While these risks will increase as the climate becomes
warmer, illnesses and deaths due to cold weather and snow are
likely to decline.
Climate change may also increase the length and severity of the
pollen season for allergy sufferers. For example, the ragweed
season in Fargo has grown 19 days longer since 1995, because
the first frost in fall is later.
y i/,

A photo of a ragweed plant, a common source of allergens in North
Dakota, Like many crops and pollen sources, ragweed will have a
longer growing season as temperatures rise. Stock photo.
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 at www.epa.Qov/