Climate science suggests that global warming will make hurricanes like Irene more destructive in three ways (all things being equal):

1. Sea level rise makes storm surges more destructive.
2. “Owing to higher SSTs [sea surface temperatures] from human activities, the increased water vapor in the atmosphere leads to 5 to 10% more rainfall and increases the risk of flooding,” as NCAR Senior Scientist Kevin Trenberth put it in an email to me today.
3. “However, because water vapor and higher ocean temperatures help fuel the storm, it is likely to be more intense and bigger as well,” as Trenberth writes

On the third point, warming also extends the range of warm SSTs, which can help sustain the strength of a hurricane as it steers on a northerly track. As meteorologist and former hurricane hunter Dr. Jeff Masters has explained:

… this year sea surface temperatures 1 – 3°F warmer than average extend along the East Coast from North Carolina to New York. Waters of at least 26°C extend all the way to Southern New Jersey, which will make it easier for Irene to maintain its strength much farther to the north than a hurricane usually can. During the month of July, ocean temperature off the mid-Atlantic coast (35°N – 40°N, 75°W – 70°W) averaged 2.6°F (1.45°C) above average, the second highest July ocean temperatures since record keeping began over a century ago (the record was 3.8°F above average, set in 2010.) These warm ocean temperatures will also make Irene a much wetter hurricane than is typical, since much more water vapor can evaporate into the air from record-warm ocean surfaces.

Also, hurricanes tend to be self-limiting, in that they churn up deeper (usually cooler) water, that can stop them from gaining strength and also weaken them.  So since global warming also warms the deeper ocean, it further helps hurricanes stay stronger longer.

One says, “all things being equal,”  because, among other things, it is possible that global warming will increase wind shear, which can disrupt hurricanes.

The media prefer to ask the wrong question — as Politico did Friday with its piece, “Was Hurricane Irene caused by global warming?”  But they do have a good quote from perhaps the leading expert on the subject:

“I think the evidence is fairly compelling that we’re seeing a climate change signal in the Atlantic, ” said Kerry Emanuel,  a professor of atmospheric science at the Massachusetts Institute of Technology. Citing other recent trends of extreme weather, including hailstorms and catastrophic tornadoes, “one begins to wonder,  if you add all those up,  maybe you are seeing a global warming effect.”

Still, he adds, “I would be reluctant myself to say anything about global warming and Irene” — but again, that I think is a function of asking the wrong question.  That’s a point Climate Central makes in its post on this subject, “Irene’s Potential for Destruction Made Worse by Global Warming, Sea Level Rise“:

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I’m re-instigating my weekend question.  The most important question I have for readers is — what topics or specific subjects would you like us to cover here in the coming year?

I try hard to figure out what content is of most value to readers.  That’s a key reason we added Stephen Lacey, to cover clean energy in detail,  since I have been so focused on climate science, politics, and the media.

I can’t guarantee we will hit every subject you propose, but I can guarantee Stephen and I will read every comment and try our best.  And I remain committed to creating archives of CP’s best content in various areas and  making that more accessible for readers.

Wind turbines at a wind farm in Kamisu City, Japan.

Japan Spurs Solar, Wind Energy by Approving Subsidies for Renewable Power

Japan approved a bill today to subsidize electricity from renewable sources, joining European nations in shifting away from nuclear power after the Fukushima reactor meltdowns in March.

The renewable-energy bill was passed by the upper house following approval by the lower chamber on Aug. 23 and was one of the last acts of Prime Minister Naoto Kan, whose support sagged over his handling of Japan’s worst postwar disaster. He said today he’s resigning after parliament passed the legislation.

The bill allows for incentives that guarantee above-market rates for wind, solar and geothermal energy. The so-called feed- in tariff created a race to install solar panels when implemented in Germany and Spain.

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