Environment

Snowpocalypse: How Global Warming Creates Gargantuan Blizzards

Climate scientists say extreme blizzards are the new normal.

Photo Credit: Sergei Butorin/Shutterstock

Severe winter storm events often prompt naysayers to mock, “Where’s that global warming?” But while the concept may seem to conflict with rising global temperatures, these storms are actually obvious evidence of man-made climate change.

Climate change, say scientists, fuels the increasing intensities of winter storms. Warmer temperatures allow the atmosphere to hold more moisture and create heavier than normal precipitation. Climatologists agree that global warming will continue to make these storms worse over time.

Weather is different from climate, scientists point out. Weather is what we experience on a day-to-day basis; climate — especially in regards to climate change — is more about long-term trends. While each describes environmental conditions, they’re on different scales of time and space. Climatologists are not in the business of watching daily and regional forecasts, they consider the larger context in which weather operates and describe long-term climate trends and how they relate to ongoing weather events.

In regard to winter weather, climatologists are looking at two different trends. First, global temperatures are 1.6 degrees Fahrenheit warmer than they were 135 years ago when measurements were first taken with accuracy. Second, what were once-in-a-lifetime snowfalls are now commonplace. There’s growing belief among climatologists that these two trends are closely related. Blizzards are generated from disturbances at the boundaries between Arctic and tropical air masses. When these fronts collide, and especially when the air mass temperatures are vastly different, it creates storms. The more divergent the air masses, the more likely the resulting storm will be large. So, as our air grows warmer and holds more moisture, the result is a lot more snow when weather fronts meet. And while you can’t attribute any one storm to the effects of climate change, a clear trend of more intense storms points in that direction.

"We're loading the dice or stacking the deck toward more intense blizzards,” research meteorologist Marshall Shepherd told CNN.

The science behind blizzards and their relationship to climate change is straightforward says Marlene Cimons of the National Science Foundation. “Warmer temperatures cause more water to evaporate into the atmosphere, and warmer air holds more water than cooler air," she says "The air's water-holding capacity, in fact, rises about 7 percent with each 1 degree Celsius (1.8 degrees Fahrenheit) of warming. The warming results in air that becomes supersaturated with water, often bringing drenching rainfall, followed by flooding or, if it is cold enough, heavy and intense snowfall.”

New York City has recently endured some massive snowfalls. In fact, five of the 10 biggest snowstorms on record have all occurred since 2003. The current storm will likely make it six. In New York, while seasonal accumulations are on the rise, it’s actually snowing much less often, so epic snowstorms and blizzards are becoming more common while “dustings” are becoming rare.

Scientists are now beginning to wonder if climate change is behind some dramatic weather events like Buffalo’s epic 7-foot snowfall in late November 2014. There, warmer than usual lake surface temperatures combined with unseasonably strong Arctic winds. While Lake Erie was still quite warm, the winds that blew over it were 50 degrees colder.  So, it was the collision between temperature extremes that juiced the lake effect snow that blanketed portions of Western New York.

Over the past decade, heavier-than-normal snowfalls observed in the Midwest and Northeast are consistent with long-term projections made by climate scientists, who factor in rising temperatures into their models. In the South and parts of the lower Midwest, the reduced snow frequency also follows these same climate models. And while overall snow is decreasing in the U.S., the snow events, overall, are becoming more intense.

"Strong snowstorms thrive on the ragged edge of temperature" says Mark Serreze, director of the National Snow and Ice Data Center. "Increasingly, it seems that we're on that ragged edge."

While snow events are becoming more intense, snow cover in the U.S. has actually decreased as warmer temperatures after snow events have prompted snow to melt quicker.  Thus post-storm flooding is also becoming a more common problem.

On the East Coast, winter storms typically form in the Atlantic off the coast of the Carolinas and move up the coast. Known as Nor’Easters, they’re typically fast moving and bring high winds and copious amounts of precipitation. These storms get stronger as they move to the northeast, typically becoming intense when they reach the colder temperatures of the northern Atlantic states.

But as these storms form over water, instead of land, they’re not easy to forecast. That’s why sometimes major snowstorms hit us by surprise and other times dire weather predictions don’t pan out. However, the science behind storm forecasting is becoming more rigorous. NOAA says that forecasting is gradually improving due to the increased quality and quantity of data, advanced computing and satellite technology, and an improvement in forecasting models. And as weather events continue to be more intense, more accurate predictions are becoming our biggest defense against the elements.

Despite being in agreement that intense weather events are more common because the Earth is warming, scientists are still very careful not to blame climate change on any specific event without doing intricate studies to see how it may apply to long-term trends. That’s why you won’t see any weather experts on television blaming “Winter Storm Juno” on climate change. But such events, when they combine to create an overall trend, has scientist agreeing that climate change is responsible for extreme weather events such as the one the East Coast is now experiencing.

Cliff Weathers is a former senior editor at AlterNet and served as a deputy editor at Consumer Reports. Twitter @cliffweathers.

 

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