Hurricane Sandy and Climate Change – Checkmate?

During election season I will occasionally tune in to a few of the news networks to get my 10 minute dose of partisan noise.  As Hurricane Sandy churned in the Atlantic and aimed herself at the New Jersey coast, I happened to come across a show that featured an economist and a political analyst discussing the nuances of tropical cyclones and climate change.  I don’t recall exactly what was said, but it went something like this:

Economist: Sandy is huge!  Why isn’t anyone talking about climate change?

Analyst [very eager to break in to the conversation]: “Yes!  Look at Sandy – an ‘S’ storm!  When was the last time we’ve had an ‘S’ storm in the Atlantic?  Usually we only make it to the H’s, or I’s, or K’s.  Look at 1992 – the ‘A’ storm that year didn’t form until mid-August!”

Now I’m sure both of these gentlemen are very bright people and I have a lot of respect for the analyst (when he talks about politics), but having them discuss hurricanes and climate is like me commentating on a grandmaster chess match – I know how the pieces move but that’s only 10% of the battle.

There was nothing particularly unusual about Sandy in the beginning – we have seen plenty of hurricanes form in the deep tropics in October, and she moved and behaved in a pretty typical fashion.  Nor has there been anything outright weird about the 2012 hurricane season in the Atlantic Ocean.   Before the season, every documented seasonal forecast of the number of named storms was above the long-term average, and the season has played out accordingly (even exceeding expectations in many cases).

But a season is usually remembered by one or two storms, and Sandy has made 2012 quite historic.  Weather forecast models accurately predicted days in advance that Sandy would have a major impact on the northeast United States.  And judging by the images and stories coming out of New Jersey, New York, and surrounding states, Sandy lived up to expectations.

As with any major storm or weather event, the inevitable question is asked: “Did climate change cause/enhance this?”  Although a definitive answer is elusive (we don’t have a big enough laboratory to create a “warming free” experiment), we can make a reasonable assessment about some of the factors that probably played a role.

Individual storms such as Sandy respond to the instantaneous ocean and atmosphere environment they find themselves in – or in a way, weather.  Climate is the palette, not the paint; it sets the scene for the actors to do their part.  So what was Sandy’s “scene”?

We know that the world’s oceans are warming – warm water means more energy is available for the hurricane.  We know that sea levels are rising, leading to larger hurricane storm surges.  And we know that coastal development continues to expose millions of people to storms like Sandy.

Most climate scientists believe that we are in for stronger hurricanes in a warmer world and that we are already seeing a move toward this new era.  But our data are just not good enough to know for sure if tropical cyclones have already been becoming stronger.  Almost all tropical cyclones, even in recent years, are not measured directly; and even when they are, we can only measure small samples of these vast storms at any one time.  This is a big reason why there are conflicting accounts on recent tropical cyclone trends.

Cyclone Center was created to help resolve these questions.  By having the public analyze 30+ years of tropical cyclone images, we will provide meteorologists with new data that can be used to reconcile differences in individual storms, as well as long-term trends.

And by the way, the last year with an ‘S’ storm in the Atlantic was 2011.  And that ‘A’ storm in August of 1992, one of only six named storms that year?  Hurricane Andrew, a category-5 storm that devastated South Florida.  To those residents affected by Andrew and Sandy, climate change is a secondary concern.

- Chris Hennon is part of the Cyclone Center Science Team and Associate Professor of Atmospheric Sciences at the University of North Carolina at Asheville

cyclonecenter.org

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5 responses to “Hurricane Sandy and Climate Change – Checkmate?”

  1. Kimberly Peterson says :

    Good article. I think long-term trends showing the effects on coastal ecosystems and in the arctic are what will ultimately prove the devestation of global warming. Too bad that LA and NY will be under water before most Americans get it.

  2. Tates says :

    ”  Almost all tropical cyclones, even in recent years, are not measured directly; and even when they are, we can only measure small samples of these vast storms at any one time. “. Would you say more about this aspect, to help a layperson understand more — how are they measured directly vs indirectly? Thanks!

    • cch001 says :

      Sure. “Directly” means that there is an instrument of some kind inside the storm, either on an airplane, ship, or buoy. Aircraft are only used to fly into storms when they form or move in the western half of the Atlantic Ocean – all other storms around the world are not sampled this way. There are several hundred buoys floating around the ocean but storms do not go over them often unless they are close to shore.

      “Indirectly” means using some kind of measurement from outside the storm environment (e.g. satellites). Forecasters use satellite pictures to estimate the maximum surface wind (the way a storm looks is related to how strong its winds are). There are other satellite data that are used to, but maybe that is for another blog.

      • Tates says :

        Thanks! Accounts of airplanes flying into hurricanes in pursuit of science (and ships, presumably unintentionally there?) would make for good reading. It occurs to me that atmospheric science and satellites have saved many lives already. Also thank you for the pallete/paint analogy, that helps in understanding/explaining.

  3. Charles Stock says :

    Thank you. Aways searching for light rather than heat.

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