Kerry Emanuel, one of the world's leading authorities on hurricanes, is a professor of tropical meteorology and climate at the Massachusetts Institute of Technology. His book, Divine Wind, delves into the history and science of hurricanes. He visited Madison last week as part of the Weston Global Distinguished Lecture series sponsored by the Center for Sustainability and the Global Environment.
David Zaks: In the "statement on the U.S. hurricane problem" a group of scientists called upon leaders of government and industry to undertake a comprehensive evaluation of building practices, insurance, land use, and disaster relief policies that currently serve to promote an ever-increasing vulnerability to hurricanes. What role do you see adaptation play alongside mitigation when assessing courses of action for dealing with global warming?
Kerry Emanuel: Even if climate science could tell you exactly what would happen to the physical climate over the next 100 years, to undertake the analysis of the optimum route for society, what's the mixture of trying to mitigate it versus trying to adapt to it, it is a profoundly complicated problem and I would be foolish to have a shot at it. Invariably it will be a mixture of things because unless someone discovers some absolutely spectacular alternative energy source, and we can't rule that out it might happen.
People will have a demand for energy, but there are things we can do; conserve, use less, all the things that are recommended in the book, of course. It is foolish to say that we shouldn't do some of that, and maybe most of it, some of it is just easy, but a certain amount of adaptation is inevitable. What concerns me is that to some extent the free market is a vehicle for adaptation, I'm not saying it is perfect, or the only extent, but if you don't let the free market do what it does because of regulation then you are handicapping yourself. Right now the regulation of insurance in the United States, which is here to stay unfortunately, has led to wholesale subsidy of risk taking in a way that is not profitable to society and I don't see why that has not carried over to the other consequences of global warming. If as government says, we expect sea level to go up 2 feet over the next 50 years, and as a consequence of that, we will pay for it. Paying people to put themselves in the way of that doesn't make any sense.
DZ: Touching on what you said about new sources of renewable energy and your work on hurricanes, would it be possible to strategically place wind turbines or other devices in the path of hurricanes to collect some of that energy?
KE: It is very tempting and there are some very almost freakish coincidences about hurricanes. If you take your typical Atlantic hurricane it dissipates about 2 x 10^12 watts of energy. That happens to equal the global electrical capacity. Which means that if you could efficiently harvest it all, you could power the world. On the average there is one hurricane going on in the world at any given time. To make that even more intriguing, you can calculate for the same hurricane the amount of fresh water it produces, as it is a great desalinator taking salt water, evaporating it and making rain. The amount of rain falling out of an average hurricane is about equal to the global human freshwater consumption. One hurricane could solve all the problems, although I don't think it is feasible because you are dealing with such excessive force and the engineering challenges would be large, so I don't see that happening, unfortunately.
On a smaller scale, in Spain they have created what they call a dynamic chimney where they create a giant greenhouse over the desert floor and in the middle of the glass you have a chimney about 100 feet high and then you have some veins. The sun makes it very hot in there and the air goes rushing up the chimney, and you apply a swirl to that, which is essentially a tornado. The beauty of it is that once it leaves the chimney it keeps going and that is important because the thermodynamic efficiency of the engine is basically proportional to the temperature difference between the bottom and the top, and 100 feet is tall enough for that temperature difference to be appreciable, but if the column of rotating air goes a kilometer into the sky, you now have a change in temperature of about 10 degrees, and they use that to generate electricity. If salt water is used instead of just the desert surface, you have a much high albedo (reflectivity) so you get more efficient generation. You get moist air going up, which means it can go higher into the atmosphere, and then the rain that comes down can be harvested into fresh water!
DZ: The future changes in global climate are often given in the change of the global average temperature, but on the ground that could mean changes to droughts, floods, disease, sea level and hurricanes. How can better understanding these changes lead us to becoming more resilient in the face of change?
KE: What happens locally, like all politics is local, will drive people to change the way that they behave. No one is going to change their behavior if you tell them that the global mean temperature is going to be 2 degrees higher. What does it mean to the average person? Nothing. If you tell them on the other hand that their flood insurance is going to double, and they see their bill go up, that is where it hits people. If the government was intelligent enough to apply huge carbon tax and you can't afford to refuel your hummer then you're going to get rid of it! You aren't going to get rid of it because your neighbor says that you are a nasty little guy, they are going to see it as being crass. The way I look at it is the way an economist would look at it. How does it affect their economic welfare? As it is already happening, people are moving out of Cape Cod because they can't insure their houses, because there is a fear that the risk of hurricanes is going up, and that is when people wake up.
DZ: Many scientists spend their time stashed away in the ivory tower, but when Katrina struck the coast, you were shoved into the public sphere partly because you published a paper in the journal Nature three weeks before the storm struck. What lessons have you learned about communicating scientific ideas to the public?
KE: That it is very hard. It is very hard even when there are no ulterior things tugging at the minds of the public. In the United States in particular, we don't really do a good job preparing the public to deal with such elementary things as uncertainty in science and when a scientist says that there are error bars on something, the public is trained because they watch all these shows where someone is covering up something, and journalists are particularly bad at dealing with uncertainties.
The most rewarding experiences were radio for the simple reason that you can talk directly to the public, so you could do the best you could do and refine that over time. On the other hand when you have to go through a journalist of any kind, even ones who are highly trained and their spirit and desires are in the right place, there is inevitable distortion that goes on. Ranging from the perfectly innocent to really viscous things that went on. Reporters tried deliberately to square me off with colleagues to blow it all out and make it into a soap opera, because frankly that sells a whole lot more newspapers in the United States than a real scientific controversy and you learn to avoid those people like the plague. To try to get the message about what you are doing out in an undistorted way to a public not trained in a lot of modern scientific issues is really hard.
DZ: Global warming and the feedbacks involved with it are inherently difficult for most people to understand. We have seen sensationalist examples, like the Day After Tomorrow, and highly scientific ones, like the IPCC. What do you think is the most effective way to educate the public about global warming, its consequences and the actions that need to be taken?
KE: I have come to the conclusion that the best possible way to do it is with scientists communicating directly to the public, not through a journalist, not on a 5 second sound bite, but going around and lecturing in villages and towns. It is a lot of work and a lot of drain on ones research and responsibilities, but the thing that is gratifying is that there is a high success rate in getting the point across, which you don't have in almost any other sphere. I don't think that sensationalism is at all productive, I think it is counter productive. Sensationalism portrays that politics are just being carried out in a different sphere, and there's nothing to it in the end. Most people react badly to what they see as alarmism and they react badly to what they see as reactionary tendencies. Scientists tend to be not reactionary or alarmists if they can talk to the public.
Really excellent post, David, thanks for tackling the interview.
Emanuel's view about "disintermediating" science by bypassing journalists is a radical though. There are not many scientists like him, willing to educate the public directly. And there are more and more journalists who are doing the hard work to get the story right. But are there good ways to get the middleman out of the picture entirely? And how to reach the numbers that the press reaches?
"On a smaller scale, in Spain they have created what they call a dynamic chimney where they create a giant greenhouse over the desert floor and in the middle of the glass you have a chimney about 100 feet high and then you have some veins. The sun makes it very hot in there and the air goes rushing up the chimney, and you apply a swirl to that, which is essentially a tornado. The beauty of it is that once it leaves the chimney it keeps going and that is important because the thermodynamic efficiency of the engine is basically proportional to the temperature difference between the bottom and the top, and 100 feet is tall enough for that temperature difference to be appreciable, but if the column of rotating air goes a kilometer into the sky, you now have a change in temperature of about 10 degrees, and they use that to generate electricity. If salt water is used instead of just the desert surface, you have a much high albedo (reflectivity) so you get more efficient generation. You get moist air going up, which means it can go higher into the atmosphere, and then the rain that comes down can be harvested into fresh water!"
Using tame hurricanes for energy generation and water provision? That's pretty bad-ass.