(Soundbite of music)

You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow.

By this time last year, the Atlantic hurricane season was off to a strong start. You remember? How could you forget Hurricane Katrina? It had already hit the southeastern coast of Florida. It was gathering strength in the Gulf of Mexico, poised to strike New Orleans on August 29th, and Katrina was the 11th named storm in the Atlantic.

This year? Well, we're only up to our fourth named Atlantic storm, and we've yet to see an Atlantic hurricane. And we have tropical storm Debbie. Debbie's moving across the Atlantic, could turn into a hurricane, but it's expected, even so if it does, to remain over open water.

Still scientists are predicting an active hurricane season, and some experts are saying that global warming is fueling the hurricane activity. Others say we're in a decades-long period of above-normal activity that will eventually run its course, and global warming may not have anything to do with it. But both scientists on both sides of the debate joined forces earlier this month, releasing a statement that's saying regardless of why we're having more hurricanes, those big storms will continue to devastate our overdeveloped, overpopulated coasts. That they say is the real hurricane problem that needs our attention now.

So for the rest of the hour, we're going to talk about hurricanes. What's in store for the rest of the hurricane season? How can we better manage our coastal areas to avoid the kind of devastation we've seen from Katrina? And if you'd like to join our discussion, give us a call. Our number, 1-800-989-8255, 1-800-989-TALK.

Let me introduce my first guest. He's joining us to talk about how the 2000 hurricane season is shaping up: James Eisner, professor of geography and director of the Hurricane Climate Institute, Florida State - Elsner, I'm sorry - James Elsner at the Hurricane Institute at Florida State University in Tallahassee. Welcome to the program, Dr. Elsner.

Dr. JAMES ELSNER (Professor of Geography and Director, Hurricane Climate Institute): Thank you, Ira.

FLATOW: Why are we seeing so many fewer tropical storms/hurricanes so far this season?

Dr. ELSNER: Well, you're correct. We haven't seen a hurricane yet this year, but we have seen five tropical cyclones. In fact, tropical depression number five is likely to become our fifth named storm of the season, so that's kind of typical for this time of the year.

FLATOW: Mm-hmm. So this is a normal year we're going through then.

Dr. ELSNER: Yeah, I think we're seeing a normal amount of activity. What's been unusual, and I think was not anticipated, was the fact that these storms have not strengthened into hurricanes, and then so that's somewhat unusual. And I think the reason for that is probably the amount of wind shear this year as compared to last year.

FLATOW: Oh, you mean, there are winds at the top that would just lop off the developing walls of the hurricane.

Dr. ELSNER: That's correct. When we look at the winds, if they're blowing in different directions at different elevations, then that tends to tip the storms over, if you will, and then they don't hang together as a one system.

FLATOW: Does that have anything to do with La Nina or an El Nino affecting the development of these storms.

Dr. ELSNER: Well, the El Nino certainly can produce shear across the Atlantic, so we're always on guard for - and we look for El Nino events to inhibit the hurricanes primarily through the wind shear that they produce across the Atlantic. But this year we're not really in a El Nino or a La Nina, so the wind shear is coming from something else.

FLATOW: Hmm. Now we might be lulled into a false sense of security then.

Dr. ELSNER: Well, I think so. I mean, typically the waters warm up first during the onset of the season, and then the shear relaxes. We just haven't seen that relaxation of the shear yet, but it appears that that is changing. In the next four to six weeks, I anticipate some of these tropical cyclones to develop into hurricanes.

FLATOW: Mm-hmm. So there was a little bit of a revised forecast a couple of weeks ago: slightly down. But you're saying it may be slightly down, but these still could be big ones.

Dr. ELSNER: Yeah. I mean, it stands to reason if we haven't seen a hurricane yet this year, the total numbers are going to be less than last year and probably even 2004. But these storms - these seasons the storms tend to come in bunches, so I wouldn't be surprised to see an average or above average season -but when all is said and done.

FLATOW: And we're in this active hurricane period that goes, what, for 20 or 30 years sometimes.

Dr. ELSNER: Yeah, there are cycles in activity, and we're certainly in the midst of a very active cycle, and so I anticipate that even for the next five to 10 years we're going to see, you know, in general above average activity, although a particular year could be quiet.

FLATOW: Mm-hmm. And so how many hurricanes do we predict this year will make landfall?

Dr. ELSNER: Well, make landfall, that's a different question.

FLATOW: Yeah.

Dr. ELSNER: The - there are factors that steer these storms, and sometimes they get into a pattern where the steering keeps them off the coast of the United States. And sometimes the steering makes it more favorable for them to track between latitudes toward the Caribbean and the United States, and I think we're still in the favorable, steering pattern for storms to approach our coast though I do expect the United States to be threatened by a couple storms this year.

FLATOW: Couple of storms. Dr. Elsner, thank you for taking time to talk with us.

Dr. ELSNER: Oh, you're welcome, Ira.

FLATOW: James Elsner is professor of geography and director of the Hurricane Climate Institute at Florida State University in Tallahassee.

Now I'd like to introduce my next guest: Judith Curry, professor and chair of the School of Earth and Atmospheric Sciences at Georgia Institute of Technology in Atlanta. She joins us today from the studios of Georgia Public Radio. Welcome back to the program, Dr. Curry.

Dr. JUDITH CURRY (Professor and Chair, School of Earth and Atmospheric Sciences, Georgia Institute of Technology): Hi, Ira.

FLATOW: Hi there. Kevin Trenberth is the head of the Climate Analysis Section at NCAR, National Center for Atmospheric Research in Boulder, Colorado. He joins us by phone from his office. Welcome back, Dr. Trenberth.

Dr. KEVIN TRENBERTH (Head of Climate Analysis Section, National Center for Atmospheric Research): Good afternoon, Ira, and hi, Judy.

Dr. CURRY: Hey, Kevin.

FLATOW: Kevin, what's the difference between the 2005/2006 hurricane seasons? You probably were listening in on that conversation.

Dr. TRENBERTH: Yes, I was. We did an analysis of the 2005 season in particular and tried to break it down, and what we did was we looked at the record of sea surface temperatures, which is a key ingredient in all of the hurricanes in the hurricane region - so this is from 10 to 20 degrees north in the tropical Atlantic. And last year was a record high year by far, 1.7 degrees Fahrenheit above normal.

And what we did was we related that to the sea temperatures over the entire Atlantic to see how the Atlantic as a whole is faring. And then we also looked at the sea temperatures over the entire globe. And the sea temperatures over the entire glove of course relate to global warming. Global influences, not just ones in the Atlantic.

And what we found was that about half of the warming last year was in fact due to global warming, about .8 degrees Fahrenheit. About .1 degree Fahrenheit was due to the Atlantic as a whole, and this relates to this thing called the Atlantic multi-decadal oscillation, which relates to the ocean currents in the North Atlantic in particular.

And then we also found that there was a contribution of about .4 degrees Fahrenheit from El Nino contributions, and this related to the fact that there was a weak El Nino - weak to moderate El Nino - in the winter of 2004/2005. And in contrast, this year there has been a somewhat weak La Nina condition, but the differences are quite startling over the critical region of the Atlantic.

And what it does in the El Nino case is it creates lighter winds and sunny skies, which warm up the sea temperatures and sort of set the conditions for a following hurricane season which is more active than normal, as long as the El Nino itself goes away before the hurricane season.

And this year, instead, the winds were quite a lot stronger. In January, there were about five miles an hour stronger in the tropical Atlantic, and that creates evaporative cooling and actually cools off the ocean. And so as we go into this hurricane season, in parts of the Atlantic - the tropical Atlantic -the sea temperatures are below normal. In other parts, especially in the eastern part of the Atlantic, they're somewhat above normal. And so, this is a key part of the difference between the two years. This year overall, the sea temperatures are much closer to normal. Last year, they were at record high levels.

FLATOW: Now, Ray, yeah. And cause, I guess blowing on the water cools it off - is basically what you're saying.

Dr. TRENBERTH: That's right. That's how the human body keeps cool as well. It's the evaporative cooling from - of the perspiration from our skin, which keeps us at our own temperature.

FLATOW: Well, you know it's interesting, as I was looking at the hurricane center's figures for the Pacific, they've already had 10 tropical storms or hurricane's named and we're only four. So they're almost where we were last year at this point.

Dr. TRENBERTH: The main hurricane activity, or typhoon activity as they call it, is certainly in the northwest Pacific. And they don't have anything much going on right at this moment. But the sea temperatures over there have been quite a lot above normal. And this follows on from the last summer season in the southern hemisphere, which is the Australian hurricane or typhoon season. And they had four category five storms in that region.

And so it seems as though the activity has sort of shifted over into that side of the world. And that's one of the things which helps to create a global atmospheric circulation that makes it less favorable for storms to develop in the Atlantic.

FLATOW: So they got what we had last year. They've got it this year.

Dr. TRENBERTH: Well, certainly in parts, China had a major typhoon that came ashore and did an enormous amount of damage.

FLATOW: Judy Curry, you've done a study that found an increase in the number of very powerful hurricanes. Are we getting bigger storms like we thought we might?

Dr. CURRY: Yes. A study that we published almost a year ago we looked at the global hurricane data since 1970 which is when we had reliable satellite data. And what we found that while the total number of hurricanes wasn't really changing, what we were finding was a shift in distribution of intensity towards more intense storms.

And in particular it was the category four and five storms that were increasing. We found almost a doubling in the number of category four and five storms from 1970 to 2004. And we associated this increase in intensity with the rising tropical sea surface temperatures which had warmed about a degree Fahrenheit since 1970.

FLATOW: You know, this being the one year anniversary of Katrina, we've been watching how people have recovered. They've been spread around the country. People have had to flee. We've watched the coastal damage trying to recover. This problem of building on the coast, you say, is just something that is really the main problem, the lesson to be learned from these hurricanes.

Dr. CURRY: Well, in the 1950s and 1960s, we had a lot of land falling hurricanes on the U.S. coast. Okay, so people weren't building. But then the hurricane activity died down, you know, in the ‘70s and ‘80s and even into the ‘90s and people started building up again.

But now we're back in an active cycle in the Atlantic, but this cycle is already way above what we saw in the 1950s and ‘60s in terms of number and intensity of storms in the Atlantic. And we're just starting into this natural cycle. So we're looking at 20 years and on into the future of this elevated level of number and intensity of hurricanes in the north Atlantic. And we've done all this development along the coast, which is very vulnerable to damage.

And the key problem with global warming coming into play, not only is it we believe it's increasing the hurricane intensity but it's also contributing to sea level rise, which is going to exacerbate storm surge problems. We saw what happened when you have a major hurricane strike a city, a coastal city that's largely below sea level, which was what happened in New Orleans where you had this horrendous damage.

Dr. TRENBERTH: I would add that it also, of course, causes extensive flooding. And the heavy rainfall from these storms is another big factor which we can also trace to aspects of global warming because it means there's more water vapor in the atmosphere. And of course it's not just a U.S. problem, as well. It's very much a global problem.

FLATOW: Talking with Kevin Trenberth of NCAR in Boulder and Dr. Judith Curry of Georgia Institute of Technology on TALK OF THE NATION: SCIENCE FRIDAY from NPR News. I'm Ira Flatow.

Dr. Curry, I saw reference to a FEMA report that said over the next 50 years, one home in four within 500 feet of the sea is going to be destroyed. Wow.

Dr. CURRY: That's a realistic prediction based on what we saw in Florida. In 2004 when they had four major hurricanes hit Florida, 20 percent of the homes in the state had some damage from those storms. So, I mean, Florida is actually getting hammered.

In the past 10 years, almost half of all the U.S. land falling hurricanes have hit Florida. And not only do they have the coastal problems but they also have storm surge problems potential associated with Lake Okeechobee. So Florida is extremely vulnerable.

FLATOW: 1-800-989-8255. Let's go to John in Anchorage. Hi, John.

JOHN (Caller): Hi. Actually I'm in Anchorage today. I actually live in Florida. So yeah, we feel very exposed, sort of leaning with our chin out in the Atlantic there.

You know, I was wondering what it would - wouldn't it make sense to stop subsidizing people living on the coast? Rather than worrying about trying to do some planning, just stop encouraging them by paying for their insurance or subsidized federal insurance. And then after a disaster hits, FEMA only helps you if you don't have commercial insurance. If you're fully insured, you're on your own. But if you're not, then FEMA will help you out, which sort of creates an interesting moral problem.

FLATOW: Yes.

JOHN: Thank you.

FLATOW: You're welcome. Dr. Curry?

Dr. CURRY: Well, that's certainly one strategy. But North Carolina and Florida have taken, you know, two different approaches. I mean, much of the, you know, the coastal land along the Florida coast, you know, is not insurable. And so the state has taken upon itself to effectively, you know, provide insurance and reimburse people for damage. And so the state is taking on a big burden because a big part of their economy is associated with tourism and people are drawn to the coast.

Now, North Carolina, which is number two after Florida in terms of getting land falling hurricanes, after getting clobbered by a number of big ones, the biggest one being Hugo in '89, which they had colossal damage on the Outer Banks. You know, the state after a few of those, the state just bought up the land and say, look, it's now state land. Don't build here. You know, so those are sort of the two different approaches that the two different states are taking.

I think the solution will probably be different for, you know, each state, depending on how necessary it is for their economy. I mean, some things are going to stay on the coast. Like you can't imagine the port of New Orleans disappearing. I mean, that's a major port because of the Mississippi. And you've got all the oil-refining activity, you know, on the gulf coast in Louisiana and Texas.

So some stuff needs to be, you know, on the coast. But so it varies from location to location in terms of what their economic and safety trade-off is in terms of dealing with this. But at some level, the whole country is subsidizing all of this, you know, in terms of when we declared a disaster area and federal funds go down to help the afflicted area. We're all paying that price.

Dr. TRENBERTH: I would just add that, of course, the increasing cost of insurance is more universal. It's not just confined to individual states. And that presumably slowly gets reflected in the cost of doing business there or the cost of housing.

But one aspect which does indeed get compensated by everyone is the federal flood insurance. The flood insurance is not done by private insurance companies but rather by the federal institutions. And as a result, it's a bit of a mess in that regard.

FLATOW: Well, hang on to that thought, Dr. Trenberth. We'll come back and talk more after this break with Kevin Trenberth and Judith Curry and take more of your calls about hurricanes. So stay with us. We'll be right back.

You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I am Ira Flatow.

We're talking this hour about this year's hurricane season with the one year anniversary of Hurricane Katrina upon us, with my guests, Dr. Judith Curry, professor and chair of the School of Earth and Atmospheric Sciences at Georgia Tech in Atlanta, Dr. Kevin Trenberth, head of the Climate Analysis Section at the National Center for Atmospheric Research in Boulder, Colorado.

Our number, 1-800-989-8255. Dr. Trenberth, I interrupted you. Did you want to finish a thought?

Dr. TRENBERTH: Well, no, it's just related to also the importance of heavy rainfalls again and the fact that flood insurance is covered by the feds rather than by individual private companies. And so that means that it comes out of the flood insurance program or, you know, taxpayers who are subsidizing that program.

FLATOW: Do you think that any, I mean, we've had countless - countless may be the wrong word because I can probably count them - but we've had dozens of scientists on in the last year talking about what needs to be done, what kinds of rebuilding should happen, what about the natural resources, the loss of land and soil in the natural barriers and on and on.

It's been a year now. Do you think any real lessons have been learned? Anybody listening any more to scientists now than they were last time when they predicted that this big one could strike?

Dr. CURRY: Well, there's been a number of workshops and task forces to try to look at this. And there's a lot of, you know, solutions on the table in terms of what we're going to do. But I think the key lesson is that we have to be very careful with our engineering solutions. Part of the problem in New Orleans was really how we engineered the Mississippi.

Okay, after some big floods we did some engineering to sort of keep the Mississippi in its tracks so it wouldn't flood. But this helped destroy, you know, a lot of the delta area and the wet lands, which when the big hurricane came - I mean, it helped contribute to a sinking in New Orleans and it helped make the whole situation more vulnerable to the storm surge when we had a major hurricane strike New Orleans.

So some of our engineering solutions can have unintended consequences. So we have to think a little bit more broadly about our engineering solutions and factor in things like global warming and ecosystem response to make sure that if we do some sort of coastal engineering that it's robust to possible changes in the climate and in ecosystems.

Dr. TRENBERTH: It's not clear to me that adequate attention is being paid to the climate change aspects in all of this. So it's not just the fact that New Orleans is sinking somewhat so there's some subsidence going on there but also that sea level is rising.

And so sea level, global sea level has risen an inch and a half in the last 12 years. So it's going up at around about one foot per century at the current rate. And the expectation is that that could increase.

And of course the key thing with the storm surge and the coastal damage is -especially the timing of when the hurricanes come ashore and there's a certain amount of a chance associated with that as to whether it comes ashore at high tide or not. And the damage can certainly be much worse at high tide than if it comes ashore at low tide. But one needs to build in the fact that sea level is going to continue to rise.

FLATOW: And that's something that it could take you decades to plan for, I mean, and to do something about, whether you decide to, you know, to build some of the flood gates or install them or raise parts of the city or give up on other parts of the city. Isn't that the kind of planning that you should be doing now for decades from now?

Dr. TRENBERTH: It seems logical to me to do that. And I certainly haven't seen the evidence that some of the lessons here have been learned enough. But on the other hand, I'm not fully aware of everything that's going on, either.

FLATOW: 1-800-989-8255. Let's get some questions. Jamie in Charlotte, North Carolina. Wonderful town. Hi, Jamie.

JAMIE (Caller): Hi. I'm just so excited about being able to talk to you, Ira, because I listen every Friday afternoon, especially the SCIENCE FRIDAY, because I just find it so interesting and helpful.

And my question is, you know, back in 1989, there was Hugo that hit. And Hugo came inland and really hit Charlotte pretty badly. I'd have to say that most of the city, from what I understand it - I wasn't living here at the time - was out of power for at least three to four days. I'd like to know if your panelists think that is it going to, is something like that going to happen again? Are more hurricanes with that kind of strength - they're talking about more hurricanes being Categories 4 and 5. Is there a greater possibility that more can come ashore like that did for Hugo?

Dr. CURRY: Actually, yes. I mean, in the North Atlantic we're under a double whammy. Not only do we have the increase in intensity, but we also have an increase in number. So as sea surface temperature increases, not only do we have more intense ones but a greater number of ones. And North Carolina is number two after Florida in getting number of landfalls. So if you just do the simple statistics, you know you're looking at, you know, a substantial likelihood of major hurricanes hitting North Carolina again in the near future.

Again, Hugo was, in terms of horizontal size, one of the biggest hurricanes we've ever seen. It was a fairly amazing storm. But again, one of the lessons of the last few years, what we thought was like a once in a lifetime storm, Hurricane Katrina, well we saw one coming along the next week in Rita - or three weeks later in Rita. So what used to be the storm of the century is not even sort of the storm of the year.

JAMIE: Do you think there's going to be a trend of - because my mom lives part of the year in Naples, Florida, and that area - Naples, Fort Myers - usually has not seen hurricanes either, between the Naples/Fort Myers area and Tampa. They haven't normally seen hurricanes, and they've seen at least two or three in the past year or to two to hurricanes as well. So are, I mean, are we just saying that there's no such thing as normal anymore?

Dr. CURRY: Well, it's changing, and the thing that - let me mention something about Tampa. Tampa ranks number two after New Orleans in terms of storm surge susceptibility for major damage. So although they haven't seen a major hurricane hit Tampa in a while, but Charley in 2004 was predicted to hit Tampa. It went south and hit Punta Gorda, but that would've been big enough to give Tampa a 20-foot storm surge.

FLATOW: Wow.

Dr. CURRY: So Tampa just missed being New Orleans. But the advantage that Tampa has over New Orleans is it's not below sea level so that water will -

FLATOW: Drain out.

Dr. CURRY: Will go, will drain out, but it's enough to cause a colossal amount of damage and flooding. So Tampa, they've been lucky and they haven't had a hit in recent years, but a major hurricane hitting Tampa is bad news.

FLATOW: Thank you, Jamie.

JAMIE: Thank you.

FLATOW: Good luck to you.

Dr. TRENBERTH: If I may, Ira.

FLATOW: Sure.

Mr. TRENBERTH: You know, six of the eight most damaging storms occurred in 2004-2005. Those were Charley, Ivan and Frances in 2004, and then Katrina, Rita and Wilma in 2005. And so you know, exactly where these storms go is largely a function of the weather situation at exactly the time when they're coming ashore, and so this relates to, you know, whether there's a cold front nearby, high and low pressure systems, and things like that, and so it's very much a chance as to exactly where they go, but sooner or later, the odds are you'll get hit.

FLATOW: We also had the season last, at least - didn't we have one in December last year, a hurricane?

Dr. CURRY: Yeah.

Mr. TRENBERTH: That's correct.

Dr. CURRY: The season is lengthening. In the North Atlantic, okay this is in the last century, we've seen the season length on average increasing 50 days.

FLATOW: Wow.

Dr. CURRY: So it's been almost five days per decade. So this is one of the major things, and this is related to, you know, the sea surface temperatures increasing, so they stay above that threshold later into the season. So we're definitely, you know, seeing record length of seasons also in the last decade.

FLATOW: And don't they -

Mr. TRENBERTH: Last year broke so many records. You know, Wilma was the strongest hurricane ever on record. Rita was the strongest in the Gulf of Mexico. Wilma was really in the Caribbean. There were the most Category 5 storms, four on record. The previous record was two. There were 28 named storms, including alpha, beta, gamma, delta, epsilon and zeta, all into the Greek alphabet for the first time ever, and the most hurricanes ever on record in the North Atlantic - 15 last year.

FLATOW: The fact that the season is lengthening, would that also have an impact of where the hurricanes go at the end of the season? Do the steering currents change a little bit? It might send them up the coast a little more?

Dr. CURRY: You know, this is the hardest thing to predict is where they're going to hit. Be sort of have, in last 10 years we've seen a concentration of activity of the major hurricanes really going into the Gulf rather than going up the Atlantic coast.

So we seem to be in a regime overall where most of the major ones are going into the Gulf. That doesn't mean to say that you can't get a major one, you know, on the Atlantic coast, but statistically it seems to be more favored going into the Gulf in the regime we're in.

Mr. TRENBERTH: As the season does go on, the place where these form and where they go does tend to change, and in particular as you get into October, November, December, you're less likely to have them in the Gulf. You're more likely to have them in the Caribbean and they're more likely to occur also off the East Coast. And so the East Coast is a little bit greater risk later in the season rather than early in the season.

FLATOW: 1-800-989-8255 is our number for questions. Let's go to Peter in Phoenix. Hi, Peter.

PETER (Caller): Hi there, Ira. Love your show.

FLATOW: Thank you.

PETER: My question is if the hurricanes really essentially cool off the ocean, did the recent heat wave in the Northeast and Central U.S. have anything to do with maybe reducing the heat and therefore having fewer hurricanes so far?

Mr. TRENBERTH: Well, the heat wave was associated with very strong what we call anti-cyclonic circulation, a very strong high-pressure system that actually went all the way across the country, and so it relates as much as anything to weather, but as we look around the world, we do find that heat waves are getting hotter and they're lasting longer, and this is even more of a tendency in other parts of the world. And you've seen especially the statistics in Europe, where they had a major heat wave in 2003 and it killed about 30,000 people.

And so it relates very much to the weather patterns at any time, but the odds also of how the heat waves are changing is also changing with climate change. It doesn't relate very directly to hurricanes, but the person who called up, the caller was correct that hurricanes take heat out of the ocean, and that's a key part of their process in the climate system that they serve.

FLATOW: Talking about hurricanes this hour on TALK OF THE NATION Science Friday from NPR News with Judith Curry and Kevin Trenberth.

In the few minutes left, one thing that we did notice last year, and I imagine that you're improving on this year, is how accurately you could predict where these hurricanes were going.

Mr. TRENBERTH: This is very true. The weather forecasts and the models that are run operationally - and we run one here also at my center, at NCAR, the tracks of these storms has been very good in recent years and it has given increased warning, and so people can take cover or evacuate or board up their windows and things like that.

The intensity is still much more of a challenge, exactly what the intensity when these storms come ashore, and so that's still something that we think can do better on, and it relates to the resolution and how big and fast our computers are. But that's been one of the big advances.

FLATOW: And we saw last year how immediately explosive these were once they entered the Gulf. Is that true this year? Do you expect the temperatures in the Gulf down a little bit more?

Dr. CURRY: Okay, well the surface temperature is a tiny bit cooler, but the depth of the warm layer is at least as substantial as it was last season. Again - so we have - the surface temperature can be a little bit misleading, and like the previous caller mentioned, is that the winds from the hurricanes do tend to cool off the ocean, both from evaporation and from deep stirring of the ocean. But the reason the Gulf was able to support so many big storms last year - you know, after Katrina you would've thought that the Gulf would've cooled off, but no, it stayed warm because that layer was so deep and Rita was able to follow very quickly.

We're seeing that same depth of the warm layer this year in the Gulf, and it's really the loop current that is the very deep warm layer. It's the same thing that caused Rita and Katrina to intensify. They really intensified rapidly when they went over the loop current with its very deep layer of warm water. And the loop current again this season is plenty deep and warm. So there's plenty of juice in the Gulf.

FLATOW: So it's setting up, things are setting up.

Dr. CURRY: Yes.

FLATOW: What should we watch for as amateur hurricane watchers to see if, you know, if we want to watch for signs that a big one is on its way or could develop? Is it set up right now, and just keep our eyes on those storms as they move across the Atlantic?

Mr. TRENBERTH: Well there's certainly another one, another depression out there that's forming at the moment, and it's projected to become a named storm, I think. So this will be - what's next in the alphabet? Is it E?

Dr. CURRY: It's E. I think it was Ernesto or Emilio. I can't remember which one.

FLATOW: I think it was Emilio.

Dr. CURRY: Emilio, okay.

FLATOW: I may be wrong.

Dr. CURRY: Yeah, but it was also projected to track into the Gulf in the early projections in terms of its path.

Mr. TRENBERTH: It's going through the Caribbean, I believe. And you know, the National Hurricane Center is certainly tracking these, and they have nice Web site where you can also look at, nhc.noaa.gov, and if you're really interested in finding out what's going on on a day to day basis, you can look at that.

FLATOW: They also have an interesting historical section there. You can go back 30 years ago and see just how many there were, you know, in that 30-year cycle.

Mr. TRENBERTH: That's right.

FLATOW: I'm sorry, Dr. Curry, did you want to jump in there?

Dr. CURRY: No, that's okay.

FLATOW: So I guess the take-home message today is even though we haven't had as many as we had last year, do not think to let our guard down that this is going to be a quieter, a much less dangerous season.

Dr. CURRY: Well it's certainly off to a later start than we were last year, but again with the season lengthening for hurricanes, there's still plenty of energy in the ocean to support major hurricane development and you know, if we can, probably looking at something like 14 named storms. That's what the forecasters tell us, with the possibility of several major hurricanes developing. And statistically a few of those are going to hit the U.S. So it would be surprising if we had less than two U.S. landfalls this year.

Mr. TRENBERTH: On the other hand, there is a very weak signs of an El Nino developing out in the Pacific Ocean, and sea temperatures are above normal out near the date line. There's a certain amount of interest in the community that maybe an El Nino will be developing later on, and so part of the atmospheric circulation patterns may be somewhat less favorable, and it may tend to stay that way. I mean, the peak season is still to come. The peak season in the Atlantic is around the 10th to the 15th of September. It's not that far away, but certainly it's worth watching.

FLATOW: All right. I've got to go. Thank you very much. Kevin Trenberth, the head of the Climate Analysis Section at NCAR in Boulder, and Judith Curry, professor and chair of the School of Earth and Atmospheric Sciences at Georgia Tech in Atlanta. Thank you both for taking time to be with us.

Mr. TRENBERTH: Thanks very much, Ira.

Dr. CURRY: Thanks, Ira.

FLATOW: You're welcome.

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