Is global warming powering hurricanes? NO: Not much we can do now, so focus investment on future power technology


By PATRICK J. MICHAELS
Today's shocking news: Global warming will exert little if any discernible effect on Florida hurricanes in the foreseeable future. Further, by the time it could, we are likely to be powered much more cleanly and efficiently, minimizing further risk. Ironically, that efficient future will arrive quicker if we do very little about warming right now.
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What about all those studies attributing the current spate of strong hurricanes to planetary warming? Most began in 1970, with the advent of global satellite coverage. Hurricanes' frequency and severity rose dramatically in the mid-1990s, when temperature patterns in the Atlantic Ocean reverted to what they were like in the mid-20th century, or 50 years ago. Back then, the proportion of Category 4 and 5 storms in both the Atlantic and the western Pacific typhoon basin (together, the world's most active tropical cyclone regions) was similar to what it is today.
This makes it plenty difficult to blame global warming for today's storms, because the same hurricane regime occurred before, when the planet was cooling.
In fact, the glib association of warming with recent hurricanes is hard to defend. The landmark computer simulation of this process, published in Journal of Climate in 2004, said, "CO2-induced [i.e. global-warming related] tropical cyclone intensity changes are unlikely to be detectable in historical observations and will probably not be detected for decades to come."
That's because, when fed an increase in atmospheric carbon dioxide that is twice the observed value for the past 30 years, by the computer's "year" 2080, the maximum wind speed increases only 6 percent. Detecting this needle in the noisy haystack of hurricane data will be daunting indeed.
But that was for a study of simulated hurricanes. What about the real world?
It turns out that a Category 3 or higher hurricane almost always requires a sea surface temperature of 83 degrees Fahrenheit. Since 1982, when weekly sea surface temperature data became available, only two of the 270 Atlantic tropical cyclones that have formed reached Cat 3 without encountering water this warm.
But, and a big but, once that threshold temperature is exceeded, there's no relationship between the strength of hurricanes and the warmer water. The chance of a storm hitting Category 4 or 5 is not enhanced by pushing the temperature above 83 degrees. Rather, each storm that encounters water this warm has the same probability of becoming a monster, regardless of how much warmer it gets.
Both the Atlantic and the Gulf, at Florida's latitude, hit this temperature threshold early every summer and maintain it well into autumn, whether there's global warming or planetary cooling.
Things are likely to be different further north, where water does not currently get to 83 degrees. We'll likely see stronger storms out over the open ocean; but the relatively cool ribbon of water west and north of the Gulfstream is not going to go away under any reasonable warming scenario. That band protects places like New York City, making the likelihood of a Category 3 strike north of Cape Hatteras much lower than it is to the south.
Here's something else you're reading for the first time: Within the forseeable future, say, 50 years or so, we know to a rather small range of error how much the planet will warm. That's because the central behavior or all of our intercompared climate models is a constant rate of warming once it is initiated. And, indeed, since the mid-1970s, that rate has been remarkably constant. The models produce different rates, and nature adjudicates which is correct: about 1.4 degree per half-century.
That's the same amount the planet warmed in the entire 20th century, so I'll bet we survive.
But, if, as a society, we decide that we must do something serious to slow down warming, dragging our feet might just be the best policy for now.
That's because there's no known suite of technologies that can slow warming enough to measure our efforts over at least the next 50 years, and probably much longer than that.
As an example, assume that every nation of the world actually reduces its production of carbon dioxide as prescribed by the United Nations' Kyoto Protocol on global warming. In fact, few countries, if any, will fulfill the protocol. But if they all did, the net warming "saved" is 0.13 degree per half-century, which is an amount too small to detect.
But Kyoto costs money - a lot.
Instead, let's save our shekels, and use them for investments in the corporations of the future, which, of necessity, must become increasingly efficient.
No one knows how our society will be powered in 2100, but historical changes tell us it will be lot different than today, and probably by something we have only a vague vision of today. But the arrival of that increasingly efficient society is delayed if we destroy investment capital right now attempting to do something we cannot.
So, as another hurricane season beckons, think of this: Florida is in a terrible position for these storms, global warming or not. But, whatever your concern about global warming, make sure that the economy has a lot of money to invest, because the future must belong to the efficient.