Andrew Sullivan, a prominent right-wing blogger, looks at the possibility of a link between global warming and the devastating hurricane that just hit New Orleans and scoffs: "As if any serious expert believes this is in any way connected."
Sorry, Mr. Sullivan, but on August 4th of this year a prominent atmospheric scientist at M.I.T., Kerry Emanuel, published a deadly serious paper in Nature called "Increasing Destructiveness of Tropical Cyclones over the Past Thirty Years," arguing that in fact it is quite possible, even likely, that global warming is contributing both to the life and ferocity of hurricanes. Emanuel writes in his introduction:
Theory and modelling predict that hurricane intensity should increase with increasing global mean temperatures, but work on the detection of trends in hurricane activity has focused mostly on their frequency and shows no trend. Here I define an index of the potential destructiveness of hurricanes based on the total dissipation of power, integrated over the lifetime of the cyclone, and show that this index has increased markedly since the mid-1970s. This trend is due to both longer storm lifetimes and greater storm intensities. I find that the record of net hurricane power dissipation is highly correlated with tropical sea surface temperature, reflecting well-documented climate signals, including multidecadal oscillations in the North Atlantic and North Pacific, and global warming. My results suggest that future warming may lead to an upward trend in tropical cyclone destructive potential, and—taking into account an increasing coastal population— a substantial increase in hurricane-related losses in the twenty- first century.
To put it in context, stories in both Salon and the LATimes point out that Emanuel's paper charts a new position in the field of hurricane studies, inspired by climatological computer modeling, and that many skeptics remain.
"I was one of those skeptics myself — a year ago," Emanuel told Michael Bustillo of the LATimes. Only after noticing a fifty-percent jump in wind speeds in hurricanes in recent years, which he said "startled" him, did he begin to rethink his position.
People are beginning to seriously wonder whether there is a [global warming] signal there. I think you are going to see a lot more of a focus on this in coming years.
On the other side of the political dial, Robert F. Kennedy, Jr., a prominent environmentalist allied with the NRDC, declares in The Huffington Post that "...the science is clear" and cites Emanuel's study as showing a cause-and-effect link between global warming and "the increasing prevalence of destructive hurricanes." He goes on to blame prominent Republican Haley Barbour for bringing global warming to his home state of MIssissippi in the form of Katrina.
Sorry, Mr. Kennedy, but the science on this subject is not nearly that clear. The leading expert on hurricane prediction in this country, Bill Gray of Colorado State University, adamantly denies not only that global warming strengthens hurricanes, but even that it exists. In an unusual readable Q&A with Gray published in September in Discover magazine, Gray declares:
Nearly all of my colleagues who have been around 40 or 50 years are skeptical as hell about this whole global-warming thing. But no one asks us. If you don’t know anything about how the atmosphere functions, you will of course say, “Look, greenhouse gases are going up, the globe is warming, they must be related.” Well, just because there are two associations, changing with the same sign, doesn’t mean that one is causing the other.
But by implying that only reckless young researchers, perhaps motivated by a desire for funding, believe in global warming, Gray over-reaches. Not all global warming believers are young, for one. Charles Keeling, the man who first discovered the cause of global warming, and tracked CO2 emissions with his Keeling Curve, and who received the National Medal of Science just three years ago, died at this year at age eighty-seven. Keeling and his team at Scripps Oceanographic Institute had no doubt about the peril of spewing what he called a "half-billion years of carbon" into the atmosphere, and neither does the man usually considered the most prominent of climatologists today, James Hansen at NASA's Goddard Institute of Space Studies, who is Gray's age. Not to mention that when the skeptical Bush Administration asked the National Academy of Sciences, this country's most respected scientific body, for an opinion on global warming, the NAS resoundingly seconded the supposedly controversial UN/IPCC report linking a rise in greenhouse gases with global warming in its 2001 Climate Change Science: An Analysis of Some Key Questions . The report opened with the declaration:
Greenhouse gases are accumulating in Earth's atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise. Temperatures are, in fact, rising.
But before Gray begins railing at the concept of global warming, he makes a simpler point that is well-accepted in the field, which is that Florida in particular has been very lucky in recent years:
The last major storm to come through Florida, before hurricane Andrew hit in 1992, was hurricane Betsy in 1965, which went through the Keys. Eight of the last 10 years have been very active—in fact, we’ve never had as much activity on the records, going back to about 1870 or so, as in the past 10 years—and yet we went from 1992 until last year with no hurricanes coming through Florida. If we look back earlier, from 1931 through 1965, Florida was hit 11 times with major storms. The major storms, the category 3, 4, and 5 hurricanes, only account for about 25 percent of the number of named storms, but they cause about 80 to 85 percent of the damage.
Emanuel echoed this assessment in a conversation with Katharine Mieszkowski of Salon:
When we looked at the historical record, we found that the frequency of storms globally hasn't really changed at all. It's about 90 per year, plus or minus 10. The frequency globally appears to be steady."
Gray was the first researcher to link hurricanes coming out of the Gulf of Mexico to global climatological phenomena, such as El Nino, and his work is still followed closely. The recent hurricanes, Emanuel explained, represent a natural fluctuation. Every 20 to 30 years, since records started being kept in the 19th century, there have been big shifts in the frequency of hurricanes in the Atlantic. Emanuel pointed that that:
For example, in the 1940s and '50s, there were very busy years, whereas the 1970s and '80s were very quiet years. And we've had a big upswing in the Atlantic beginning in about 1995. That's all natural.
The real problem, according to Emanuel and Gray and another well-known expert in the field, Roger Pielke, Jr., is that in the "quiet years" thousands and thousands of people have moved in and built in Florida and along the Gulf Coast. Emanuel told Salon:
A lot of people in my business had been, even in the 1980s, warning anybody who would listen -- which was very few, it turned out -- that there was going to be this upswing in hurricanes. It's not rocket science. We've been building all this stuff in Florida during this lull that lasted 20 years. We built all this stuff, and it's waiting to get creamed. There's been a fantastic amount of construction. A lot of people have built homes on the water. And nobody really listened. And now all of those predictions are exactly coming true. But it doesn't have much to do with global warming.
Or, as Pielke put it in a paper just published at the American Meteorological Society:
There is overwhelming evidence that the most significant factor underlying trends and projections associated with hurricane impacts on society is societal vulnerability to those impacts, and not the trends or variation in the storms themselves (Pielke and Landsea 1998). Growing population and wealth in exposed coastal locations guarantee increased economic damage in coming years, regardless of the details of future patterns of intensity or frequency (Pielke et al. 2000).
Which brings us back to the situation on the ground (and underwater) in New Orleans. In a sense, as the NYTimes pointed out yesterday in an editorial called Nature's Revenge unusual for its lack of wishy-washiness, this disaster was entirely predictable.
The damage caused by a hurricane like Katrina is almost always called a natural disaster. But it is also unnatural, in the sense that much of it is self-inflicted. New Orleans is no exception, and while the city has been spared a direct hit from the storm, its politicians and planners must rethink the bad policies that contributed to the city's vulnerability.
But it's also true that protecting a city threatened by a hurricane, surrounded by levees, and--after evacuation orders--populated mostly by people too poor to flee, is a city that desperately needs all the help it can get from the National Guard. To prevent this sort of civic crisis was the original purpose of the Guard. But when the Bush Administration decided to fight a war overseas with reservists, that meant, according to a story published in the Army Times, that at least six thousand National Guard troops were not on hand in Louisiana and Mississippi that could have been there to help avert the disaster or quell looting.
It gets worse. According to Will Bunch, a senior writer with the Philadelphia Daily News, in a furiously eloquent post on his blog Attytood and at Editor&Publisher, the Bush administration not only diverted the National Guard from the New Orleans area, it also stiffed levee maintenance and building for the sake of the war in Iraq.
"...after 2003, the flow of federal dollars toward SELA [levee rebuilding and flood control] dropped to a trickle. The [Army Corps of Engineers] never tried to hide the fact that the spending pressures of the war in Iraq, as well as homeland security -- coming at the same time as federal tax cuts -- was the reason for the strain. At least nine articles in the Times-Picayune from 2004 and 2005 specifically cite the cost of Iraq as a reason for the lack of hurricane- and flood-control dollars.
Read the whole post. It's quite stunning how reckless and irresponsible the White House has been with the people and property of the city of New Orleans.