Archive for February 14th, 2013

**Apologies to anyone who was alerted twice of this post, but issues occurred during the initial post that did not allow for the most updated iteration to be posted in its entirety**

After enduring blizzard conditions of historic proportion brought on by the Nor’Easter Nemo last weekend, life in much of the Northeast is finally returning to normal.  This storm fascinated me for a number of reasons.  First off, I think those at the Weather Channel should be given an Emmy for literally covering falling snow for more than two consecutive days.  If you thought CBS struggled to fill airtime during the roughly 35-minute blackout during the Super Bowl, try covering incremental snow accumulation for more than 48 hours straight! While I will never rely on the Weather Channel for a forecast,


their quality coverage undoubtedly deserves a Ron Burgundy “don’t act like you’re not impressed.”


The second phase of fascination with Nemo revolves around my work on the communication of climate change impacts in the political realm. After the record-breaking snowstorm I eagerly anticipated what was sure to be a heavyweight throw-down between political parties arguing this storm’s climate change significance.


But as Nemo grew in size and intensity to resemble more of an impressive hurricane than classic Nor’Easter from space,


slamming areas like Milford, CT (38 inches) and Portland, ME (all-time record 29.3 inches) with incredible snowfall accumulations, the political debate of Nemo’s relevancy in the climate change discussion was less impressive than the 7 snow “events” Washington, DC has observed so far this winter that have an aggregate accumulation of not even 2 inches of snowfall. (Forgive me, my meteorology background combined with living in DC would not allow me to let this absurdly unfair fact go unmentioned!)

On the heels of the warmest year in observed U.S history that saw the second most $1 billion extreme weather events (record year: 2011), second costliest storm the U.S. has ever endured in Sandy (record: Katrina in 2005), second costliest year from extreme weather events (record year: 2005), and even mention of specific extreme weather and climate events in the President’s latest State of the Union Address, how does Nemo receive so little mention in the political space?

My hypothesis is that while a storm of Nemo’s magnitude might seem like prime meat for political debate, this was actually a double-edged sword for both parties.  Those wanting to keep the drumbeat going on climate change and extreme weather events of recent years ran the risk of attempting to make a connection between an historic event that is associated with cold temperatures and snowfall with a topic that has been generally branded as “global warming.” The same fact might lead some to think the cold characteristics of Nemo made it great material for climate change skeptics, who might argue the event serves as evidence that we could actually be cooling, but skeptics ran the risk of leaving themselves susceptible to the wide range of recent counterpoints — such as 2012 being the hottest year on record in the U.S and Nemo being yet another extreme weather event that might add to the 25 +$1 billion events the U.S. has encountered in the last two years — making it likely a losing battle.

So where does Nemo fit in the climate change discussion? To help answer that question I’ll leave you with some key excerpts from Kevin Trenberth’s (former head of the Climate Analysis Section at the National Center for Atmospheric Research) input in a recent piece posted on thinkprogress:

  • Every storm and “event” is unique. It always has unique ingredients. So it is hard if not impossible to take apart, because any piece missing means the storm behaves differently. So event attribution is not well posed. Instead we look for the environment in which the storm is occurring and how that has changed to make conditions warmer and moister over the oceans.
  • Ingredients for a big snow storm include temperatures just below freezing. In the past temperatures at this time of year would have been a lot below freezing but the ability to hold moisture in the atmosphere goes down by 7% per degree C (4% per deg F), and so in the past we would have had a snow storm but not these amounts.
  • The moisture flow into the storm is also important and that is enhanced by higher than normal sea surface temperatures (SSTs). These are higher by about 1 deg C [almost 2°F] than a normal (pre-1980) due to global warming and so that adds about 10% to the potential for a big snow.
  • Warmer than normal winters favor snow storms (See “We get more snow storms in warm years”). A 2006 study, “Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States” found we are seeing more northern snow storms and that we get more snow storms in warmer years. (*Note: This last bullet is not a statement from Kevin Trenberth, but a follow up statement made by Joe Romm in response to Kevin Trenberth’s point in bullet #2)

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