Looking Back on Winter: Part I

The arrival of spring in temperate climates means more hours of daylight, showers and flowers.  Despite the general mood improvement from the dark days of winter, we should not be quick to forget the controversies surrounding this past season.

Winter 2010, deemed by media outlets as Snowmaggedon and Snowpocalypse, was the snowiest season on record in parts of the Mid-Atlantic such as Washington D.C.  Why did the snow cause so much hysteria about climate science in the media?  Can the season tell us anything about long term change in the climate system?

Some confusion can be explained first with a short refresh of Psych 101.  A typical challenge in addressing the complexities of climate is the ability to translate scientific data into concrete evidence.  The Center for Research on Environmental Decisions (CRED) explains that global surface temperature rise of a few degrees seems minimal to most people, considering the range of weather regularly experienced.  When the US government shuts down for a week due to record breaking snow, as it did during this winter season, it is likely to influence popular opinion.

CRED researcher Eric Johnson, featured in a NY Times exploration on weather psychology explained that we have a tendency to overweigh the concrete, immediate evidence in front of us even if it is not relevant to the bigger picture.  Johnson describes another useful anecdote about choosing treatment for a short term gain even when it may have lasting negative impacts.  It is important to remember that day to day or season to season fluctuations in weather patterns are a product of natural variability that exists in the climate system, such as for example the Arctic Oscillation.  Atmospheric Scientists explain the Arctic Oscillation as a see-sawing pressure system over the North Pole.  It was in its negative phase this winter, which drove cold air into mid-latitude regions, including much of the Northeastern United States.

However, were the winter’s storms above and beyond that natural variability, perhaps attributable to climate change projections?

Temperature increases, even one degree Celsius, are the first of many further changes in the climate system.  Increasing temperatures in the atmosphere increase its ability to retain moisture. An atmosphere with more moisture can release that moisture in extreme precipitation events.  Thus future projections include heavier rainfalls and snowfalls in some places but also longer lasting periods of drought in others.  Think about the humidity experienced in the air right before a strong thunderstorm.  On a smaller scale, this is what an atmosphere with more moisture will experience: it will hold onto that moisture and eventually release its extra “holdings” in heavier events.

Another important note in the NY Times weather psychology piece came from Janet Swim, Psychology Professor at Penn State.  Swim described that our perceptions or mental models of climate change are difficult to overcome.  Effective climate change communication must recognize that many people’s mental model of climate change includes images of melting glaciers and hot temperatures, rather than an increase in the frequency of extreme weather events.  This mental model of warming is likely due to the media’s use of the term “global warming” as opposed to “climate change.”  CRED experts also highlight the importance in using the different terminology, as climate change “avoids the misleading implication that every region of the world is warming uniformly and that the only dangerous outcome of growing greenhouse gas emissions is higher temperatures, when that, in fact, is just the tipping point for a cascade of changes in the earth’s ecosystems.”

Finally, there is an extremely important distinction to be made in separating weather from climate. One weather event cannot explain long term climate change projections. More on that to come in Part 2!  Both sides in the debate should not jump on this season as concrete evidence for or against climate change.  However, we can use this record-breaking snow season to reflect on what it can potentially tell us about long term weather pattern changes and on how we ourselves respond to such “extreme” experiences.