[McGINNIS] So, is the weather we're seeing truly extreme, and if so, is it climate change or is it just nature? Joining us for theMIX, Climatologist and senior fellow in environmental studies at the Cato Institute, Dr. Patrick Michaels. His new book, Climate Coup, is coming out a bit later this year. And in New York, Dr. Michio Kaku. He's a physics professor at the City University of New York and author of the forthcoming book Physics of the Future. Thank you both for being with us. Patrick, it certainly seems like extreme weather -- is it?

[MICHAELS] Well, we can actually take a look at what we call circulation indices in the atmosphere. There's been a recent study over the entire 20th century. The hypothesis that they are becoming more variable or more accelerated just didn't stand up when it was looked at. And we can look at tropical cyclones, the feared hurricanes of the fall. And we can make hypotheses about changes in the Arctic ice, like we saw in the piece before, and that that would be related to changes in snowfall and cold. That's a very easy thing to test, to see what the correlation is between the amount of Arctic ice up there and the cold in the center of the country. That's never been done, and I suspect it would not hold up.

[McGINNIS] These are normal weather patterns if you look at it over the long term?

[MICHAELS] Yeah, there's no major change that you can find.

[McGINNIS] Based in science. Dr. Kaku, what do you say? How does science explain what you think, which is that there are more frequent occurrences of severe weather?

[KAKU] Well, snowstorms in general are caused by dry, cold Arctic air coming down from Canada, hitting moist, warm air coming from the Gulf of Mexico. And there are two effects going on. One is a short-term effect. We have, in the Atlantic Ocean, the North Atlantic oscillations around Iceland. In the Pacific, we have cold water around La Niña, and those two fluctuations are, in fact, apparently pulling down more cold Arctic dry air. However, we also have a long-term effect, an average effect -- global warming -- which is helping to create more moisture in the air. And the combination of more Arctic air coming down from the Arctic, hitting more moist air, on average, will create more snowstorms.

[MICHAELS] You just put forth the hypothesis that you would have a detectable increase in snowstorm frequency and magnitude in the center of North America. I don't think that's going to hold up --

[KAKU] Not frequency, magnitude. We're not talking about more hurricanes happening. We're talking about stronger hurricanes happening, but the frequency is probably going to be roughly the same.

[MICHAELS] But we've already tested that hypothesis on hurricanes with NOAA's Cyclone Intensity Index.

[KAKU] No, we haven't, because we're talking about long-term effects now. You make a very important mistake. We're not talking about minor fluctuations here, which take place year by year. Long-term average effects. What's happening now is consistent with global warming, but you can't say in any one particular year, "Aha, it's global warming" -- it's an average effect.

[MICHAELS] Correct, I was looking at the 20th-century analysis, that's long-term. The Cyclone Intensity Index begins in 1979. That's decades, and it's at its lowest value. These hypotheses are not doing very well.

[McGINNIS] Dr. Kaku, where do you tell the average person to look for information? There's such wide disparity in this debate.

[KAKU] We can, of course, call NOAA, but the origin of the debate is very simple. I'm a physicist. We like to model things precisely, using computers. But when it comes to the weather, it's chaotic. We have short-term effects, which are causing the sharp decrease in temperature, but we also have long-term effects, and it's very hard to separate the two sometimes. And these computer models are not 100% correct.

[McGINNIS] Well, it certainly is a spirited debate, and we are going to put you guys on hold for a moment. More of theMIX and our discussion on climate change when we return, plus...looking for energy deep underground. Many believe geothermal promises abundant clean energy but could all that digging be dangerous? Some say it's causing earthquakes. That story later on "energyNOW!"

[TEXT ON SCREEN] The Golden Toad is thought to be the first species to go extinct because of climate change. It was last seen in 1989. www.nature.org.

[McGINNIS] Welcome back to theMIX. We're continuing our conversation about whether global warming is the reason for all the severe weather we seem to be seeing. We're back with Dr. Michio Kaku in New York. He's a physics professor at the City University of New York. Climatologist Patrick Michaels here in the studio; he's senior fellow at the Cato Institute. Another guest joining us now from Lubbock, Texas, is Katharine Hayhoe; she is an atmospheric scientist and a professor at Texas Tech. Thank you all for being with us today. Tell me about your work at Texas Tech and how it leads you to the conclusion that we are seeing more severe weather and it is attributable to climate change.

[HAYHOE] The five years that I've lived here, we have had the longest dry period ever recorded and we have had two record-breaking 24-hour rain events, just in five years. Now, we can't say that any one event is because of climate change. There's always a good chance of something happening naturally. But what we can say is that with these type of events, climate change is loading the dice in favor of them happening.

[MICHAELS] The fact of the matter is, since the 1920s, extreme weather-related deaths around the world have dropped -- hold onto your hats -- 98%. In other words, we can talk all we want about these changes, but it's very clear that people are adapting them to the point that they're irrelevant.

[McGINNIS] Dr. Kaku, what do you say to that? Do you think something needs to be done? Are we adapting?

[KAKU] If you take a look at China, we have massive drought in China, affecting the world economy. I was in Brazil three weeks ago, where we had massive mudslides, something that we haven't seen in three or four generations, killing 500 people. In Australia now, we have the flooding of the century going on, with a huge chunk of Australia basically underwater. So, global warming does not mean uniform warming. It means on average, swings, more extremes -- droughts in China, flooding in Australia, snowstorms in the United States. And it's an average effect.

[McGINNIS] Katharine Hayhoe, let's talk action. What needs to be done, if anything?

[HAYHOE] There's no reason to do something just for climate change. There's lots of different reasons to find new, homegrown energy sources, so we don't have to depend on foreign oil, to create new ways of getting energy that give us clean air and clean water, and a better future for our children. It's also important to conserve the resources that we have. Just like our grandparents told us back in the 1930s, conserve our water; conserve our energy. Take care of the planet that we've been given.

[McGINNIS] Patrick, is climate change, as a cause for this severe weather, a reason to do those things?

[MICHAELS] What we really need to do is to preserve our adaptive capability, and that means that we have to have economies that are capable of dealing with the weather that we have and with the weather that we're going to get. Again, the fact that the number of deaths from extreme weather has dropped by 98% tells you that we are adapting and we are dealing with the changes that occur.

[McGINNIS] Dr. Kaku, do you think we need to do more?

[KAKU] I think we have to do more. If people are dying less because of extreme weather, we're just getting better at it. But the long-term is, we may see some of our great cities underwater, and I don't want to see that happen. I don't want see dikes around Manhattan. I don't want to see dikes around the great capitals of the world. And I don't want to see Greenland begin to thaw out. So, I think we should begin a process of energy efficiency, renewable technologies, going green -- because it's prudent, because we need an insurance policy, because if global warming is really kicking in, on average, it's going to mean tremendous economic dislocation taking place.

[McGINNIS] All right, Dr. Michio Kaku, author of Physics of the Future, with the City University of New York, thank you so much. Patrick Michaels with the Cato Institute, thank you so much, And Katharine Hayhoe at Texas Tech, thanks again.