Hurricanes in a Warming World

Eh, what the heck…I’ll come out of the closet and spice up this theology-heavy blog.

As I recently posted on my old blog (which I falsely predicted would be resurrecting), the much-touted link between climate change and more frequent and more intense hurricane turns out to be much trickier than you would think.  The catastrophic and hyperactive 2004 and 2005 Atlantic hurricane seasons naturally led people to fish about for an explanation for the chaos, and it wasn’t hard to find a few scientists ready to line up and point the finger at global warming.  It stood to reason, of course, that if hurricanes fed on warm ocean water, and the world was getting warmer, including the oceans, then hurricanes would get more numerous and stronger.  At least, that was the bastardized form of the argument that was repeated often enough in the media to become accepted fact.  The actual scientists recognized that other factors would come into play and the relevant papers generally projected an actual decrease in number of tropical cyclones, with a slight increase in average intensity, and a marked increase in maximum potential intensity (which depends largely on water temperatures).  

This summer, other possible complicating factors emerged, as I discussed in that old post.  Coming into this season, projections were for a hyperactive Atlantic hurricane season–one of the most active on record.  What materialized instead from June 1st to August 20th was almost complete inactivity–sure, Alex spun up into the second most intense June hurricane recorded on June 30th, but after that, there were only two feeble and short-lived tropical storms, Bonnie and Colin.  Most remarkably, this inactivity coincided with well below-average eastern Pacific activity and historically low western Pacific activity, so that, on the whole, the Northern hemisphere was on track for record lows.  

Now, what else was going on at this time?  Well, much of the planet, particularly Asia, was baking–in eastern Europe’s case, under temperatures without equal in the historical record.  It was theorized that the super-heated landmasses caused a pattern of sinking air over the oceans, reducing atmospheric instability and putting a lid on cyclone development.  So global warming might actually suppress cyclone development?  Sure enough, no sooner did the Great Russian Heat Wave break in mid-August than the Atlantic saw a period of truly remarkable hurricane activity, producing over the next four weeks 9 named storms and five hurricanes–all five of them major hurricanes and four of them Category 4s–and breaking or challenging several interesting records in the process (for more on these, see below).  This pushed Atlantic hurricane activity from half the normal to date on August 20 to double the normal to date on September 20.

However, this shift did not occur in the Pacific Ocean, which remains at the lowest levels in the 30-year data period, thus the heat wave correlation thesis may not work so neatly after all.  The inactivity in the Pacific basin indeed is so pronounced that it seriously calls into question the thesis about climate change and hurricane activity.  See, while Atlantic hurricane activity gets much more press than cyclones in the rest of the world (for obvious reasons), it in fact only comprises only about 1/10 of global tropical cyclone activity on average.  And if the whole planet (more or less) is warming, and a warming planet means more cyclones, then it should mean more cyclones the world over.  But in fact, global tropical cyclone activity has collapsed in half since 2005, and has been sitting for a couple years now at record lows (with the records again going back 30 years)–and the highest years were back in the mid-90s. 

Why do we in the Anglo-American world labor under the delusion that we are living in a time of dangerously active and ever-worsening hurricane seasons?   Simply because the North Atlantic is in the midst of one of its well-documented twenty-year cycles of elevated activity–meanwhile, the rest of the world enjoys relative placidity.  So let’s hear the end of this careless pseudo-science, until there’s data to support it.

 

Of course, it’s not that simple either–it never is.  While these statistics are based on Accumulated Cyclone Energy measurements, probably the best way of comparing overall cyclone activity (and which does take intensity into account), they hide the curious fact that most of the cyclone basins in the world have recorded their most powerful storms on record in the past few years.  Other apparent anomalies have emerged that provide plenty more grist for the mill of those pushing hyping the effects of climate change on hurricanes.  In the Atlantic, at least, we have seen in recent years several records fall for speed of intensification, which is perhaps the scariest kind of record to be broken, and more and more storms seem to be pushing the envelope of what were thought to be plausible intensification rates.  Likewise, we have seen storms forming and strengthening in parts of the ocean unaccustomed to strong hurricanes.  Just in the past week, for instance, we had by far the furthest east Category 4 on record (Hurricane Julia), the first ever major hurricane in the Bay of Campeche (Hurricane Karl), and Hurricane Igor slammed into Newfoundland as its worst-ever hurricane, not to mention capturing the record for the largest Atlantic hurricane ever (in size).  Are these proof that something scary is happening over our oceans as a result of climate change, something that may make these already enigmatic storms even more unpredictable?  Or does this just mean that we don’t have enough data yet to accurately understand and compare what’s going on?  

Whichever is the case, science needs to be just a bit more humble in the claims it makes about these mysterious monsters.

4 thoughts on “Hurricanes in a Warming World

  1. Rick Littlejohn

    Thanks for the update. Interestingly from an environmental point of view, in 1000 years whatever happens to climate over the next couple of centuries due to fossil fuel consumption will have returned to the long term underlying trend as all the fossil fuels will have been consumed and the resultant CO2 will have turned into carbonate deposits on the ocean floor. The long term environmental issue that counts is extinction of species, which is horrific even an evolutionary perspective and even more so from a creationist one. Unfortunately it is overshadowed by the climate change issue.As for climate change…something interesting is happening…whatever it is and whatever causes it. That stuff about superfast intensification is fascinating.

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  2. science needs to be just a bit more humble in the claims it makes about these mysterious monsters.Brad, can you link to the particular scientific papers you are criticising here? You said above that the scientific prediction is that it is likely that a warming climate will reduce the total number of hurricanes (though likely increase maximum intensity), and that those papers have for some time been acknowledging that this is one area of climate change that is less well understood (all three of these claims are clearly made in AR4).So, it seems to me that your main beef is with the media (and perhaps with some activists) rather than the scientists, who are doing just what they should be doing.And if the whole planet (more or less) is warming, and a warming planet means more cyclones, then it should mean more cyclones the world over.This doesn't follow. Warming is not evenly distributed and is far from the only factor influencing hurricane formation.

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  3. PS I assume you've read this? An advanced version will no doubt be coming out before too long.And when you say that in this post you are coming out of the closet, what did you mean? (And as if you hadn't already come out of the closet and spiced up the blog with your post on homosexuality… ;-))

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  4. Brad Littlejohn

    Hey Byron, I figured I could bring you storming in with rebuttals with this post. :-)You are right that my last sentence was not entirely on the mark…part of that was due to my common malady of Concluding Sentence Paralysis–that is, the sudden onset of writer's block at the very end of the essay, which often leads to somewhat injudicious conclusions. So, you’re right, my main beef is with the media distortion of the science, not with the science itself, which has been generally more careful in its conclusions. However, I did not want to entirely exempt the scientists from critique, for three reasons. First, while emphasis has shifted to the change in intensity, rather than number, of tropical cyclones, claims about increase in number of cyclones have not disappeared. I do not have the time to read too widely regarding this stuff, but a main source I have in mind here is Jeff Masters, the meteorologist who founded the Weather Underground and who has for several years now used his Tropical Weather Blog to ring the alarm bells about global warming with increasing hysteria. He has an uncanny way of connecting whatever remarkable tropical activity there is with global warming, but managing to ignore whenever there is remarkable inactivity (as this season in the Pacific). Read his blog for any period of time and perhaps you’ll understand my frustration. Second, too many of the studies have focused too much on activity in the North Atlantic alone–more on this below. Third, even the intensity connection is not entirely clear-cut. As I mentioned, the statistics I have been relying on here (and I meant to provide a link–here it is) measure based on ACE, which does take intensity very much into account. Of course, there is a different calculation method, the “Power Dissipation Index” which cubes, rather than squares the intensity of a storm, and which does therefore show a slight upward trend over the past thirty years, though mainly in the North Atlantic, not the Pacific.Now regarding this remark: “And if the whole planet (more or less) is warming, and a warming planet means more cyclones, then it should mean more cyclones the world over.
 This doesn't follow. Warming is not evenly distributed and is far from the only factor influencing hurricane formation.”You’re right, I oversimplified here. No, the whole planet doesn’t warm evenly, and the warming could affect different hurricane development regions differently. But what I meant to say is that if claims are being made about tropical cyclones as a whole, then global activity must be considered. If claims are being made only about one basin, then this needs to be made clear, and attention needs to be given to why warming might increase hurricane activity in one basin, while retarding it in another (which could explain the opposite trajectories of Western Pacific vs. Atlantic cyclone activity since 1995). or whether warming was the best explanation for these correlations. There may well be studies that have given attention to this; I just haven’t encountered them. And if so, then here also perhaps my beef is with the media, not the science, or with the popular science, rather than the serious science. I’ll have to read more to find out, I guess. Regarding links–no, I don’t have links on hand to some of the research I had in mind…it’s been quite a while since I read most of that stuff, and more recently it's just been Jeff Master's blog. Thanks for your link…some of the relevant papers are linked on that site. The main thing that emerges from all these articles is that the relationships are exceedingly complicated and poorly understood, which was my chief point…science needs to be humble.

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