Why has there been so much snow in the U.S. if the overall climate is warming?

Envision a world with a warming climate. What does it look like? Warmer weather all-year-round? Less snow during the winter? Maybe no winter at all?

More snow during the winter months probably isn’t the first thing that would come to mind while picturing a warmer climate; however, record-breaking snowstorms have been one of the many outcomes of climate change. Keep reading to learn more about how changes in the Atlantic causes more snow in the U.S. and what you can do to help mitigate global climate change.

Within the most recent half of the 20th century, there have been about twice as many extreme snowstorms in the U.S. The areas that have seen this change the most are the Northeast, Midwest, Southeast and Great Plains. Some areas have experienced up to 71% more snow between 1958 and 2012.

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Percent changes in the amount of precipitation falling in heavy events from 1958 to 2012 for each region. There is a clear trend toward a greater amount of precipitation being concentrated in very heavy events, particularly in the Northeast and Midwest. (Figure courtesy of the National Climate AssessmentSo what causes this increase in snowfall if the overall climate is warming? The most prevalent causes include warmer ocean surface temperatures in the Atlantic, the reduction of Arctic sea ice and the change in atmospheric circulation.

Warmer Ocean Surface Temperatures:

During the past few decades, the Arctic and northern hemisphere have warmed approximately twice as rapidly as previously observed. A warmer ocean creates an increase of moisture in the air. This increase in moisture leads to greater amounts of precipitation in the form of rain and snow.

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Warmer air leads to more evaporation and more precipitation. A change in just 1 degree F may lead to a 4% increase in water vapor. (Photo courtesy of Climate Central)

Reduction of Arctic Sea Ice:

We have all seen the heart-breaking picture – the polar bear floating on a lonely chunk of ice in the middle of a vast ocean. This depiction of the Arctic is, unfortunately, an accurate look at life for a current-day polar bear. Sea ice is disappearing at an alarming rate, with the amount of Arctic sea ice lost since the 1980s as large as 40% of the contiguous United States, and in 2017, a new record was set for the lowest amount of sea ice cover during the winter. This loss of Arctic sea ice, in addition to affecting wildlife, also increases the prevalence of snowstorms here in the U.S.

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The lack of contiguous sea ice causes polar bears to have to travel long distances between ice masses. This increase in calories burned from swimming between the ice masses causes them to lose the stored fat that they need to survive. Capturing prey is also more difficult since polar bears usually catch seals by breaking the cone-shaped ice that seals use to come up for air. With the lack of ice cover, this method of hunting is no longer an option. (Photo courtesy of National Geographic)

The warming ocean and the reduction of Arctic sea ice create a cycle that continues to increase ocean temperatures and speed up the loss of sea ice. This relationship is known as Arctic Amplification. With warmer waters, less sea ice is able to form. When less ice is covering the Arctic during the winter months, open water creates more energy in the form of heat. This is because the open ocean is a darker color than ice, which absorbs more heat.

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The image above shows how much warmer or colder a region is compared to the norm for that region from 1951 to 1980. The average global temperature from 2000 to 2009 has increased by 0.6°C (1.08°F) but the Arctic has seen the biggest change of 2°C (3.6°F). (Photo courtesy of NASA)

To tie these changes of temperature in the Arctic back to our main question about how this causes more snowstorms in the U.S., this increase in temperature and loss of sea ice in the Arctic not only increases the frequency of storms and the amount of precipitation – it also causes a change in the way weather patterns circulate through the atmosphere.

Change in Atmospheric Circulation:

Although the details of atmospheric circulation may be a little confusing, the main take away is that increasing Arctic temperatures are changing how air circulates from the Arctic to the U.S., which causes storms to move at a slower rate. These slower-moving storms cause precipitation to take place for a longer period of time since it takes longer for the storm to move from one area to the next. Thus, if a snowstorm is moving over the U.S., more snow will fall on the areas it covers since the storm is moving at a slower speed.

How you can help:

With an issue as large as global climate change, it can be overwhelming when thinking of solutions; however, each person has the capability of making a few small changes in their everyday life that can make a difference.

Here are three very easy changes you can make this winter to do your part in fighting climate change:

  • Insulate windows. There are many ways to make sure the warm air is staying inside your home and the cold air is staying out this winter. One option is to have thick curtains and keep them closed at night. You could also install insulating film, which is available at almost any hardware store.

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    Properly insulating your home can eliminate 1,100 pounds of carbon per year. (Photo courtesy Energy Smart Show)
  • Change furnace filters. A dirty filter limits airflow through the furnace, causing a higher energy demand. Replace filters every three months while your furnace is in use.

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    Having a clean filter can save 5% in energy use, eliminating 175 pounds of CO2 per year. (Photo courtesy American Home Shield)
  • Turn down the thermostat. To start, try setting your thermostat to 68° while you’re home and 66° while you’re gone or sleeping. Eventually, you may find yourself being able to be comfortable in a 60° house. The lower the temperature, the higher the savings for both you and the earth!
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    Lowering the thermostat by 1 degree during the winter can save you 2% on your heating costs and reduce carbon emissions by about 782 pounds per year. (Photo courtesy ATCO EnergySense)

    To recap – the large amounts of snow we have seen in the U.S. is a result of increasing temperatures in the Arctic, the loss of sea ice and the change in atmospheric circulation. These changes create more snow because the warmer air holds more moisture, creating more precipitation. Snowstorms are moving at a slower rate, which equates to more inches of snowfall in the areas hit by the storm. You can make a difference in decreasing the amount of carbon in the air this winter by insulating your windows, changing the filter in the furnace every three months and turning down your thermostat by at least one degree. If you make these simple changes, you could eliminate about 2,000 pounds of carbon!

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