INTERVIEW ASSIGNEMNT: Answer in written form to hand in.
1. Answer the questions shown in red.
2. Select three other important statements (highlight and number the statements on the
article) and briefly explain their meaning and/or impact.
MIT Professor Kerry Emanuel talks about his book “Divine Wind: the History and Science of Hurricanes.”
Emanuel’s latest research, published in Nature Magazine, shows a startling global increase in hurricane
strength and duration, which he correlates to rising sea temperatures linked to global warming.
RealAudio for this Story
Download this Story
Links Related to this Story
TV ANNOUNCER: And welcome back to our ongoing coverage of the aftermath of
hurricane Katrina. I'm Kim Perez...
GELLERMAN: Kerry Emanuel doesn't usually watch much tv, but as the devastation of
hurricane Katrina unfolds he's been glued to the Weather Channel on the little television he
keeps in the kitchen of his home in Lexington, Massachusetts. These days, he's resisting the
temptation to say "I told you so."
TV ANNOUNCER: Part of the Twin Span bridge on I-10 into New Orleans is gone...
GELLERMAN: Kerry Emanuel is a professor at MIT's Earth, Atmospheric and Planetary
Sciences. He has a new book called "Divine Wind: The History and Science of Hurricanes."
And his latest research, published in a recent issue of Nature Magazine, correlates the
greater intensity and frequency of hurricanes with global warming. Even he was surprised
by what he found.
EMANUEL: Well I looked at the record of hurricanes in the Atlantic and the western part of
the North Pacific, and I looked at a measure of the production of energy by hurricanes over
their entire life. When you look at this measure of energy consumption it's gone up by about
70 or 80 percent since the 1970s. It's a really big increase. It was startling. And we're trying
to understand why.
Part of it I think we do understand: that when we looked at the whole issue of wind speeds,
we didn't think about the issue of the duration of events. And this particular metric that's
gone up 70 or 80 percent is also depending on the duration of storms, and that duration has
gone up quite a bit. It's gone up about 50 percent in the last 30 years. And that explains part
of the difference, but not all of it, to be sure.
GELLERMAN: Well, how close is the correlation between the surface sea temperature and
hurricanes? [1. WHAT TYPES OF DATA ARE NECESSARY TO CONFIRM THE
ANSWER TO THIS QUESTION? BE AS SPECIFIC AS POSSIBLE.]
EMANUEL: Well, this particular measure of energy consumption is very closely tied to sea
GELLERMAN: So, the higher the temperature of the sea surface, the more intense and the
greater the duration of hurricanes?
EMANUEL: That's right. And we predicted that you should see about a ten percent increase
in wind speed for every two degree sea change. That theoretical prediction has been backed
up since then by lots of modeling that has been done elsewhere by other groups.
GELLERMAN: So what you expected to see was a nine percent increase and you're actually
getting 80 percent?
EMANUEL: Yeah, 70 to 80 percent. So the prediction was way off.
GELLERMAN: So you have scientists who are supplying you with the global warming
EMANUEL: That's right.
GELLERMAN: And you feed that into your models.
GELLERMAN: And, so right now you've gotten, what, about a five temperature degree
increase in the surface temperature of the water?
EMANUEL: That's right.
GELLERMAN: And it could go up one degree? Two degrees?
EMANUEL: That's right. The predictions are one to two degrees. Now, ironically, one of the
things that isn't in the models is the feedback to the climate system from hurricanes
themselves. We always talk about hurricanes responding to climate change as a one-way
proposition--climate changes, the hurricanes respond.
It's quite possible that it isn't one-way. It may very well be two ways: that the hurricane
activity feed back on the climate system. And one of the ways that that can happen is
through the effects of hurricanes on the upper ocean, which is really what motivated my
Nature study to begin with. They churn cold water to the surface, and they also export heat
in the ocean to high latitudes.
So, one of the theories about this feedback would suggest that the effect of hurricanes on
global warming itself would be to reduce that warming in the tropics, but to increase it at
high latitudes. We think. And if that happens, then the projected warming at the latitudes
of, say, New England or Europe, would be more than what is being forecast. But, the
warming of the tropical regions would be somewhat less than is forecast.
GELLERMAN: When you look at the planet globally and you're looking at hurricanes, what
is the effect of man-made warming upon the intensity and duration of the hurricanes we
have now, and may have in the future?
EMANUEL: We think we're seeing a signal that the intensity of hurricanes is going up
owing to global warming, and their duration is increasing, as well. And this has us worried.
In terms of the influence of this on the rest of the world, I think it can't be stressed enough
that in the United States we have been enormously successful in reducing the loss of life. As
horrible as Katrina has been – and it is horrible, sort of a worst-case scenario – so our
problem is economic. That's our big problem.
But in the rest of the world, in the developing world, the problem is loss of life.
[EXPLAIN THE PREVIOUS HIGHLIGHTED PASSAGE. WHAT DOES THIS
STATEMENT MEAN?] You know, tropical depression Jean last year – it was just a
depression – killed almost 2,000 people in Haiti. Hurricane Mitch in 1999 killed 11,000
people in Central America. And a decade before that, a hurricane in Bangladesh killed
100,000 people. Now, this is really, really terrible, and our suffering ought to be weighed
GELLERMAN: Professor, when you watch the Weather Channel and see the destruction
from this Hurricane Katrina, do you say, "I told you so"?
EMANUEL: No, I think we're not quite that heartless to think that. It's a terrible, terrible
scene of devastation. And I think I speak for my colleagues that, about the time Katrina
came off the west coast of Florida and emerged into the Gulf, and the track forecasts were
revised to bring it over or near New Orleans, we all felt this terrible sense of dread because
people had talked about nightmare scenarios. We sort of played them through in our own
minds and in our discussions, and this was certainly one of them.
And on top of that, Katrina's track took it over a feature in the Gulf of Mexico called the
Loop Current, where the warm water that you normally find in the Gulf in the summertime
runs particularly deep. And we have known for some years that that's very favorable for the
rapid intensification of hurricanes.
GELLERMAN: So do you expect to see more hurricanes of the sort of Katrina coming our
way in the next few years?
EMANUEL: Well, yes and no. Certainly we're going to a lot of Cat 4 and 5 storms. Whether
they hit land, and whether they hit a populated part of the land, is entirely a matter of
chance and that makes it impossible to answer your question in a reasonable way.
Let's just take Hurricane Brett. Now, not too many people, unless you live in Texas,
remember Hurricane Brett. It was 1999. It was a Cat 4 hurricane when it went into the Texas
coast. If it had gone into Houston or Galveston it would have been horribly devastating.
What really does make a difference, of course, is that the population of these coastal regions
has exploded. And people are...their risk is being subsidized by federal policy, and state and
local policy, and that is what the real problem is. It's not meteorological, it's societal. We're
putting all this wealth in harm's way and we're getting creamed.
GELLERMAN: Do you do anything different here, New England, to prepare your house, to
prepare your family, for disasters?
EMANUEL: Massachusetts actually is an interesting place. It does have a decided hurricane
risk. Right now, it is almost impossible to buy a private insurance policy, homeowner's
policy, in Cape Cod because almost all of them have pulled out. They've pulled out because
new estimates of hurricane risk in Cape Cod suggested that they couldn't charge a premium
high enough to cover their exposure. The state won't let them, and even if it did, people
probably couldn't afford it. And so we're in kind of a crazy situation where very wealthy
people on the beach in Cape Cod are being insured by a state insurance pool which was set
up primarily to insure the uninsurable poor in inner cities. And guess who's paying for
that? The rest of us.
GELLERMAN: Well, meteorology's about the prediction business. Looking forward, what
do you see happening?
EMANUEL: Certainly I think most of my colleagues would join me in saying the next ten
years are going to be a rough ride in the Atlantic, even forgetting about global warming
because of these natural cycles. We're in an upswing and this isn't rocket science, we just
look at the past record and extrapolate it into the future. We're in an upswing, it's bound to
last another five or ten years. And if we have levels of hurricane activity that we had in the
1940s and 50s we're in trouble.
Now, what has everybody in my profession so concerned – and we've been concerned for
decades – is the confluence of a huge upsurge in the coastal population with a natural
upswing in the number of storms in the Atlantic. And maybe global warming, you know, if
you wait long enough will also start to show up in those statistics.
GELLERMAN: So global warming right now you don't think is having an influence? Or it is
having an influence?
EMANUEL: No, if you look at the global record of hurricane activity, you do see a
pronounced upward trend that began in the 1970s, which is very highly correlated with an
upward trend in the tropical ocean temperature. And the people who study tropical ocean
temperatures believe that this recent upward trend is mostly a consequence of global
warming, and that's why we're worried that we're now seeing a global warming signal in
hurricanes. But the big near-term problem is demographic and natural.
GELLERMAN: Professor, thank you very much.
EMANUEL: You're quite welcome.
GELLERMAN: MIT Professor Kerry Emanuel's new book is called "Divine Wind: The
History and Science of Hurricanes." His latest research appears in the magazine Nature. You
can find the link on our website, www.loe.org.
[MUSIC: Arvo Part "Lamentate: Spietato" from LAMENTATE (ECM – 2005)]