Hurricanes and climate change action


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Bike beside the Rideau Canal in spring

At several points in the past, I have mentioned the possibility that the majority of people will not be willing to accept serious action on climate change until at least one big, unambiguously climate related disaster has taken place. The same point is made in Joseph Romm’s book but, whereas I have speculated that it could be vanishing icecaps or large-scale climate induced human migration in Asia, he seems to think that Atlantic hurricanes striking the United States may make the difference.

There is good reason to find this plausible. The strength and frequency of hurricanes both have a lot to do with sea surface temperature (SST). While it isn’t feasible to attribute the occurrence or harmfulness of a particular storm to climate change, it is relatively easy to show a correlation between rising global temperature, rising SST, and more severe hurricanes. Simulations conducted by the U.S. National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory led to them concluding that “the strongest hurricanes in the present climate may be upstaged by even more intense hurricanes over the next century as the earth’s climate is warmed by increasing levels of greenhouse gases in the atmosphere.” Within decades, rising SSTs could make the kind of extraordinary hurricane seasons that have proliferated since 2000 the low end of the new scale.

This matters partly because a hurricane-climate change connection would affect Americans directly and very visibly. Insurance prices would rise further, at the same time as more areas became uninsurable and serious questions arose about whether to rebuild at all in some places. The cost trade-offs between insurance, protective measures like higher levees, and storm risk would be thrown into sharp relief. The perceived damages associated with climate change would also shift from being associated with people outside of North America at some distant point in the future to being both physically and temporally immediate.

Obviously, it would be better if serious measures to combat climate change (eliminating non-CCS coal, pushing hard on energy efficiency, building dramatically more renewable capacity, etc) could come about simply as the result of a reasoned assessment of the IPCC’s scientific conclusions and projected associated costs. If, however, it is going to take disasters before people and politicians are ready to embrace real change, we should hope that they will come early, carry a relatively small cost in human lives, and not exacerbate the problem of climate change in and of themselves, as fires and ice loss do.

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{ 11 comments… read them below or add one }

Milan April 8, 2008 at 4:26 pm

Two related items:

So what happened to the 2007 hurricane season?
Hurricanes this past year were unpredictably … average
Posted by Joseph Romm (Guest Contributor) at 1:51 PM on 04 Dec 2007

11.28.2007 10:06AM
The 2007 Atlantic Hurricane Season: A Post-Mortem
An Oddly Quiet Year for Hurricanes
By Chris Mooney

R.K. April 9, 2008 at 9:57 am

There seems to be a fair amount of scientific disagreement about hurricanes and climate change.

Of course, this might just be the next step back in the scorched earth retreat of the climate change deniers. It is all but impossible for a non-expert to know if this debate is synthetic and manufactured by Exxon and British Petroleum, not to mention American Republicans aware of how big a motivator a climate change-hurricane link could be.

. April 9, 2008 at 10:01 am

IPCC 4AR – Working Group 1

Global Climate Projections

Tropical Cyclones (Hurricanes and Typhoons)

Results from embedded high-resolution models and global models, ranging in grid spacing from 100 km to 9 km, project a likely increase of peak wind intensities and notably, where analysed, increased near-storm precipitation in future tropical cyclones. Most recent published modelling studies investigating tropical storm frequency simulate a decrease in the overall number of storms, though there is less confi dence in these projections and in the projected decrease of relatively weak storms in most basins, with an increase in the numbers of the most intense tropical cyclones.

. April 9, 2008 at 10:56 am
. April 10, 2008 at 1:07 pm

Where they’ll stop, no one knows

The Atlantic hurricane season could include more than a dozen tropical storms this year, with about half of them strong enough to become hurricanes, according to researchers at N.C. State University.

Of course, the most useful information is where they’ll land and no one can tell you this until you are safe in the motel, 100 miles away from your coastal property, after evacuation.

. April 11, 2008 at 3:48 pm

Climate change blamed for disastrous storms; Worst is yet to come, expert warns

Canadian municipalities and their residents need to better prepare themselves for severe weather, like Thursday’s heavy snowfall, which will continue to happen more often and at greater severity thanks to climate change, says an expert in the field.

(Calgary Herald; 20080411)

. April 11, 2008 at 3:48 pm

Scientists predict climate change could cause more flooding and droughts

Scientists predicted Thursday that climate change in coming decades will cause more flooding in the Northern Hemisphere and droughts in some southern and arid zones.

(The Journal-Pioneer (Summersid; 20080411)

. April 15, 2008 at 2:07 pm

Forecast for big sea level rise
By Richard Black
Environment correspondent, BBC News website, Vienna

Sea levels could rise by up to one-and-a-half metres by the end of this century, according to a new scientific analysis.

ToryC July 24, 2008 at 1:11 pm

“Let us suppose that the great empire of China, with all its myriads of inhabitants, was suddenly swallowed up by an earthquake, and let us consider how a man of humanity in Europe, who had no sort of connection with that part of the world, would be affected upon receiving intelligence of this dreadful calamity. He would, I imagine, first of all, express very strongly his sorrow for the misfortune of that unhappy people, he would make many melancholy reflections upon the precariousness of human life, and the vanity of all the labours of man, which could thus be annihilated in a moment. He would too, perhaps, if he was a man of speculation, enter into many reasonings concerning the effects which this disaster might produce upon the commerce of Europe, and the trade and business of the world in general. And when all this fine philosophy was over, when all these humane sentiments had been once fairly expressed, he would pursue his business or his pleasure, take his repose or his diversion, with the same ease and tranquillity, as if no such accident had happened. The most frivolous disaster which could befall himself would occasion a more real disturbance. If he was to lose his little finger to-morrow, he would not sleep to-night; but, provided he never saw them, he will snore with the most profound security over the ruin of a hundred millions of his brethren, and the destruction of that immense multitude seems plainly an object less interesting to him, than this paltry misfortune of his own.”

. May 22, 2009 at 2:08 pm

21 May 2009
Of tempests, barren ground and a thousand furlongs of sea

Guest commentary by Ron Miller, NASA GISS

Several studies have shown that hurricane activity is generally reduced during years when there is a thick aerosol haze over the subtropical Atlantic. The haze is comprised mainly of soil particles, stripped by wind erosion from the barren ground over the Sahara and Sahel. These particles are lifted into the atmosphere and carried by the Trade winds as far as the Caribbean and Amazon basin. Plumes of dust streaming off the African coast are easily recognized in satellite imagery, and were even described by Charles Darwin during his voyage on the Beagle.

The amount of dust crossing the Atlantic has been measured at Barbados since the mid 1960s (aptly by Prospero and colleagues). These measurements show a threefold increase in dust between the original part of the record and the mid 1980s at the peak of the Sahel drought, when the region was unusually vulnerable to wind erosion. African dust crosses the tropical Atlantic within the Saharan Air Layer (SAL), an elevated duct of air between about 2 and 5 km in altitude. Because of its continental origin, this air is not only dusty but extremely dry.

There is an observed anti-correlation between dustiness and tropical cyclone days in the Atlantic (Evan et al, 2006). This anti-correlation might indicate the a direct influence of dust on hurricanes, or a connection between the dry air the dust resides in and hurricanes, or might even be related to a much larger scale pattern which controls both hurricanes and dustiness. If there is a connection, one hypothesis is that entrainment of dry SAL air rapidly strangles a developing cyclone because of the low humidity that accompanies the dusty air, while the dust itself has no direct effect. An alternative hypothesis is that the reduction in sunlight beneath the dust layer cools the ocean surface, whose temperature is a well-known predictor of hurricane activity (at least at the basin scale). Thus it is plausible that decadal variations in dustiness could contribute to decadal variations in hurricane activity, but how big might such an effect be?

. June 1, 2009 at 10:41 am

Nature: Hurricanes ARE getting fiercer — and it’s going to get much worse

Atlantic tropical cyclones are getting stronger on average, with a 30-year trend that has been related to an increase in ocean temperatures over the Atlantic Ocean and elsewhere. Over the rest of the tropics, however, possible trends in tropical cyclone intensity are less obvious, owing to the unreliability and incompleteness of the observational record and to a restricted focus, in previous trend analyses, on changes in average intensity. Here we overcome these two limitations by examining trends in the upper quantiles of per-cyclone maximum wind speeds (that is, the maximum intensities that cyclones achieve during their lifetimes), estimated from homogeneous data derived from an archive of satellite records. We find significant upward trends for wind speed quantiles above the 70th percentile, with trends as high as 0.3 plusminus 0.09 m s-1 yr-1 (s.e.) for the strongest cyclones. We note separate upward trends in the estimated lifetime-maximum wind speeds of the very strongest tropical cyclones (99th percentile) over each ocean basin, with the largest increase at this quantile occurring over the North Atlantic, although not all basins show statistically significant increases. Our results are qualitatively consistent with the hypothesis that as the seas warm, the ocean has more energy to convert to tropical cyclone wind.

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