Climate 'Weirdness' Throws Ecosystems 'Out Of Kilter.'

August 14, 2012

Guest: Michael Lemonick

DAVE DAVIES, HOST: This is FRESH AIR. I'm Dave Davies, in for Terry Gross, who's off this week. We've read plenty of stories over the past couple of years about punishing heat waves and crop-killing droughts, not to mention forest fires, floods and tornadoes. Is this global warming or just a bad run of luck?

Our guest today, Michael Lemonick has some answers from Climate Central, an independent nonprofit group of journalists and scientists, which is devoted to sorting out the best scientific knowledge about climate change and delivering that information to the public and policymakers.

The group has a new book, a 200-page guide aimed at answering key questions about climate change in plain language. It's written by Lemonick and Emily Elert. Lemonick is a veteran science writer who wrote for Time magazine for 20 years and has authored several books. His latest, coming out this fall, called "Mirror Earth," is about scientific efforts to find a planet similar to our own. His book with Climate Central is called "Global Weirdness: Severe Storms, Deadly Heat Waves, Relentless Drought, Rising Seas and the Weather of the Future."

Well, Michael Lemonick, welcome to FRESH AIR. Let's talk a little bit about some of the basic science of this. Carbon dioxide obviously is a major greenhouse gas, but I learn in your book that water vapor is one of the other greenhouse gases. How does that work? I mean, how does that fit in with carbon dioxide?

MICHAEL LEMONICK: Yeah, water vapor is a very important greenhouse gas. There's much more of it, physically, than there is carbon dioxide in our atmosphere. And the reason we don't talk about it so much is that it doesn't change on its own. So carbon dioxide increases, sometimes, from natural causes, volcanoes go off. And now it's increasing because humans are putting more of it into the atmosphere. So that's changing the situation.

With water vapor, it doesn't change naturally. It doesn't just rise and fall. It can rise in response to a warming of the Earth. So today we are putting carbon dioxide in the atmosphere, it's heating the Earth, that's making more water evaporate into the atmosphere, and it's adding a further greenhouse warming. So it's on top of the warming induced by carbon dioxide. But water vapor doesn't change on its own.

DAVIES: Now we've had - we've measured temperatures with thermometers, what, 100 years or something like that. How do we know what the temperature of the Earth has been in the past, and what have studies shown about the important trends?

LEMONICK: Well, one very important way we know about the temperature in the past is that if you go to Greenland or to Antarctica and drill deep into the ice, what you find is air bubbles trapped as snow fell thousands of years ago, hundreds of thousands of years ago, and air was trapped in among the snowflakes, and when it was compressed into ice, those air bubbles have remained.

So they're actually time capsules that show you exactly what the atmosphere was like at any time up to about 800,000 years ago. And so what we can look at directly is the amount of carbon dioxide that was in the air, and that has gone up and down. And you can also deduce what the temperature was by the chemical characteristics of the snow itself, the ice that was once snow.

Depending on what the temperature was, the different chemical composition of the ice will say it was warmer or colder, and that's how we know that temperature and CO2 have varied with each other quite directly for at least 800,000 years ago.

If you go back further, you need to use more indirect measurements: chemical composition of the rocks and level of the sea. You can look at ancient shorelines, and that tells you where sea level was a million years ago, five million years ago, and that's kind of a direct measurement of how much ice was or wasn't caught up in the ice caps in Greenland and Antarctica.

DAVIES: And when people have looked at trends in the Earth's temperature, they come up with the hockey stick. Tell us about the hockey stick.

LEMONICK: The hockey stick is a measure of temperature trends over the last 2,000 years or so, more or less. As you say, we don't have thermometers going back that far. We have a number of different measures that show what temperature was like over that period. So the hockey stick just talks about temperature.

One of the things we look at is tree rings. Another is those bubbles in the ice I was talking about, a number of other measures in dead organisms that thrive in carbon-dioxide-rich or warm atmospheres. And putting together a lot of different lines of evidence, no one of which is definitive, you get this curve that shows that the temperature was more or less steady for about 2,000 years ago, not exactly steady, and that in the 20th century, it's suddenly taken a serious upward slope.

The temperature is rising much more quickly and dramatically during this past century than it has any time in the last 2,000 years.

DAVIES: Now, we often hear that there is a general consensus among most serious scientists that the climate is changing, that the Earth is warming, and it's the result of human activity. And then we'll read someone saying aha, not so. I mean, for example there was a letter published in the Wall Street Journal, an article I guess in January by 16 scientists stating, among other things, that we haven't seen a lot of warming for more than a decade, that the warming trends have been much smaller than predicted by these scientists.

Should we be concerned by arguments like that?

LEMONICK: Well, we should be concerned in the sense that these arguments are often false and misleading and divert attention from what's going on. The consensus about climate change and about the human contribution to it is highest among people who actually study the topic.

The letter you refer to in the Wall Street Journal was signed by a lot of scientists who don't study the topic but who have, you know, affiliations with organizations or universities like Princeton and who give the impression of knowing what they're talking about, and frequently they don't.

And I could address that particular letter if you like, but the people who understand what's going on with the climate system best are in agreement that we are actually changing the climate.

DAVIES: All right, well, let's just take a couple of the specific things that you hear, like there hasn't been any warming trends, say, in the last decade, say since 1998.

LEMONICK: Right, and so that's valid. There has been a much slower warming trend, let's say, than in the previous 30 or 40 years. And that is often trumpeted as evidence that the predictions of rising temperatures are false. The problem is that nobody ever made a prediction that temperatures would rise steadily, like, you know, like a steadily rising line, and that's because in addition to the strong human influence on climate, there are also natural cycles of climate change.

And those things are happening at the same time, and so climate scientists actually expect that you will have times when the warming is faster, times when the warming is slower. It's not a straight line going up. And so the claim that this slower warming over the past 15 years is - invalidates climate science is - it's just false, and it's ridiculous.

DAVIES: And then there are all the famous, you know, leaked emails from those British scientists. I mean, the most famous is one in which one of them says the fact is we can't account for the lack of warming at the moment, and it is a travesty that we can't. What about that?

LEMONICK: That addresses exactly that same point of that slower warming. What this scientist was saying was we know that there are other factors besides human greenhouse gases that affect the climate and affect the temperature, and this slowing that we've seen is clearly due to some sort of natural phenomenon, but we don't know what it is, and we really need to understand that as well as we understand human contributions.

DAVIES: And in general, though, when those emails are examined more carefully by folks who understand them, what, if anything, do they tell us?

LEMONICK: What they tell us is that the scientists who were sending the emails are human beings who are dismissive of people they disagree with and think that - you know, they don't mind calling I guess a fool a fool, if that's how they feel, in private, in what they consider to be private conversations.

When you look at the science that they're talking about, a number of commissions and inquiries and so on have actually looked at the emails, looked at the science done by these scientists, and in every case they've come out and said the science is not in question. None of what they said in the emails - it may reflect that they were having a cranky day or that they would like to, you know, to criticize these people more openly than is appropriate in a public sphere, but at the end of the day, the science that they were talking about is not at all in question.

And so bad behavior in private by scientists, that's just a terrible thing.

DAVIES: But they don't show the scientists saying to one another ah, this is a fraud, I don't really believe this, we're putting one over on people?

LEMONICK: They absolutely do not say anything like that.

DAVIES: We're speaking with Michael Lemonick. He is a science writer and has published several books. He's the author, with Emily Elert, of the new book "Global Weirdness." It's the work of Climate Central, which is a nonprofit science and journalists organization. And we'll talk more after a break. This is FRESH AIR.

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DAVIES: If you're just joining us, we're speaking with Michael Lemonick. He's a veteran science writer. He's published several books, and he's the author with Emily Elert of a new book "Global Weirdness." It's about the science of climate change, and it's the product of scientists and journalists in a nonprofit organization called Climate Central.

Let's talk about some of the effects of climate change. What is the accumulation of carbon dioxide doing to the oceans?

LEMONICK: Well, this is something that doesn't get talked about all that much because we usually think of climate change and global warming as synonymous, but in fact while it's true that the primary effect of carbon dioxide buildup is to warm the Earth and to change the climate, some of that carbon dioxide is absorbed by the oceans.

And when water absorbs carbon dioxide, it becomes more acidic. So we talk about ocean acidification as another side effect of greenhouse gases, and in fact the oceans are getting more acidic, and that trend is likely to continue. That has some implications for sea life, especially organisms that form shells.

In an acidic environment, it's harder to form a shell, and because a lot of these organisms are at the very base of the ocean food chain, there could be some real disruptions to that part of our food supply.

DAVIES: Can you give an example?

LEMONICK: Well, corals, for example, are organisms that have more trouble in acidic waters, and while they're not at the base of the food chain, they provide habitat for a lot of fish that we do depend on. So that's one example.

DAVIES: What about ocean levels rising? How much of that are we seeing, and what might be causing it?

LEMONICK: We have seen sea level rise by about eight inches overall, worldwide, since about 1900. Part of that is because water actually expands as it gets warmer. So it's trying to burst out of its bed in the sea. Another reason is that ice is starting to melt in Greenland, in mountain glaciers, in Antarctica. And just as important or even more important, the ice in places like Greenland in glaciers is starting to slide more quickly to the sea and dump chunks of ice in even before they melt.

And those effects combined are indeed raising sea level. It's higher in some places, lower in others. It depends in part on local conditions. But the average has been about eight inches. Now, there is every reason to believe that is not only going to continue but going to accelerate as the temperature gets warmer, and while we don't have an exact number, the best projections to date suggest that sea level could rise by another two feet to six feet by the year 2100.

The best sort of median estimate is about three feet, and three feet of sea level rise could actually be quite drastically dangerous.

DAVIES: What would happen?

LEMONICK: Well, you know, we tend to think that, well, the sea rises three feet, and anything three feet or less above sea level will be underwater, and that actually leaves most of the coastal cities still mostly out of water. I mean, you lose some beaches in Miami Beach and so on. And the sea will encroach to a degree, but a much more significant problem is that whenever a storm comes along, it drives a storm surge ahead of it. And that washes deep into the land. That causes major flooding. We sometimes forget that the damage in New Orleans in 2005 from Hurricane Katrina came not from the wind, not from the rain but came from the storm surge ahead of that storm.

And all of those storm surges are going to be starting from a level three feet higher, which means that they have much greater potential to drive inland, to wash over barrier islands and to really inundate the coasts. So many, many millions of people and trillions of dollars of infrastructure are in serious danger if those projections are correct.

DAVIES: You also write about the diminishing of the Arctic ice cap, and we could reach a point where it's, in effect, ice-free at least during the summer. Is that - why is that significant?

LEMONICK: That is significant. Right now, it's the middle of August, the minimum ice extent every year in the Arctic Ocean is in the middle of September. So we're getting close to the minimum. And for the past 30 years or so, that minimum extent has been smaller and smaller, on average, every summer, not literally every summer. But there's less and less ice covering the Arctic Ocean in the summers, especially in the late summer.

And it's significant for a couple of reasons. One is that the less ice there is up there to reflect sunlight, the more sunlight is absorbed by the ocean water below. So it's kind of another feedback mechanism that we talk about where the less ice, the warmer the water, the warmer the air in the Arctic and the less ice will form or the more slowly ice will form the following winter, and it'll be thinner, and it'll be more prone to melting the following year.

And so it's kind of a spiraling downward cycle of ice cover, and it may well be, in fact it's likely, that during part of the summer, the Arctic Ocean will be essentially ice-free within 20 years, maybe even sooner. It's - so by itself that's significant because it exposes more and more water to warming and it sort of boosts global warming.

But the other thing is that with a big mass of relatively warmer air sitting up there in the Arctic, that can seriously alter weather patterns further down. So it can push the Jet Stream around. It can do unpredictable things to our weather.

DAVIES: Well, let's talk about some of the ways - you know, one thing that we hear is that climate change will bring us more extreme weather phenomenon: floods, tornadoes. Why would that be?

LEMONICK: Well, as far as we know, there's no link yet been established with - between climate change and tornadoes. There may well be such a link, it's plausible because, you know, tornadoes happen in the climate, and the climate is changing, but we don't have anything useful to say yet about tornadoes.

The reason that extreme weather events like droughts and heat waves and torrential rainstorms, however, will happen is in part because it is getting warmer, more water, as I said before, evaporates into the atmosphere. That means there's more to rain out when there is a rainstorm. So extremes of dryness on the one hand and torrential rains on the other hand are quite likely to become more frequent.

We're also expecting more severe and longer lasting and more intense heat waves, and this summer happens to be a summer when we've had quite a few intense heat waves. We're also having a very intense drought in the U.S. But in other parts of the world, they're having more rain.

So the weather is pushing in both directions, which is a consequence of all of that water evaporating.

DAVIES: Will we see more hurricanes or more intense storms?

LEMONICK: The best thinking - and I keep putting it this way. I keep saying the best thinking because I don't want to pretend, and climate scientists won't pretend that they know everything. So they make their best estimates, they make their best projections, and then they rethink them as more evidence comes in.

So the best thinking to date - a few years ago, let me start there. A few years ago, people thought hurricanes get their energy from warm seawater. The seawater's getting warmer, we're likely to have more hurricanes. Now more sophisticated analysis suggests that while the water is getting warmer, wind patterns may change in such a way that will actually prevent the formation of some hurricanes.

So the bottom line as of today is we are expecting, in the Atlantic anyway, fewer hurricanes overall but more powerful hurricanes when they do occur.

DAVIES: And why would they be more powerful?

LEMONICK: Well, and so the greater power does come from the higher temperature of the seawater. The fewer comes from the fact that wind patterns will blow some of them apart before they can truly form. But once they form, they're likely to get more energy from the ocean and become more intense.

DAVIES: You mentioned that sea level appears to be up about eight inches since the beginning of the 19th century. Temperature's up about 1.3 degrees, I guess, since - in the last 100 years or so. It doesn't sound like a lot. Why do people - people might look at that and say this is nothing to be alarmed about.

LEMONICK: Right, you're exactly right. In fact, I don't know what the temperature is outside today, say it's at the moment 80 degrees. If I walked out, and it was 80 degrees, and then I came inside and walked out again, and it was 81.3 degrees, I wouldn't even notice. It's - the temperature varies so much more than that from day to night and from winter to summer that it feels like that's insignificant.

But when you're talking about an average rise in the entire planet's temperature of that much, it's actually quite significant. And rather than try and prove it to you with some kind of mathematical formula, I like to use the fact that in the transition from the last ice age, when the last ice age, we had glaciers down in New Jersey and all over the Northern Hemisphere, and the planet was frigid, it was about eight degrees Fahrenheit colder, on average, back then than it is now.

So the transition out of the last ice age into the present, much warmer, period reflected only a change of about eight degrees Fahrenheit. That doesn't sound like a lot, either. It was enough to completely change the face of the planet. We are now talking about a likelihood of an eight-degree-or-so rise in temperature at the high end of the projections over the next 100 years. That is a much rapider change than the couple of thousand years it took at the end of the last ice age.

So you're right, it doesn't sound like a lot, but that amount of temperature rise, over a short period of time especially, can profoundly change the face of the planet.

DAVIES: Michael Lemonick is the co-author of "Global Weirdness," a guide to the science of climate change from the group Climate Central, an independent association of journalists and scientists. Lemonick will be back in the second half of the show. I'm Dave Davies, and this is FRESH AIR.

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DAVIES: This is FRESH AIR. I'm Dave Davies in for Terry Gross who is off this week.

We're speaking with Michael Lemonick, a veteran science writer, who is the author, along with Emily Elert, of "Global Weirdness," a guide to the science of climate change produced by Climate Central, an independent group of journalists and scientists devoted to sorting out the best scientific knowledge about climate change and delivering it to the public and policy makers.

Let's talk about what's going to happen in the future as climate change advances, or if it continues to advance. You know, we hear a lot about computerized weather models. Now are climate models fundamentally different?

LEMONICK: They're not fundamentally different, but they're trying to do a different thing. So a weather model is trying to predict exactly what is going to happen six hours from now, eight hours from now, tomorrow, next week. They're trying to predict the exact conditions for a specific place, which is a very, very, very complicated thing to do.

Climate models are trying to predict average conditions for much larger areas. And so, you know, it's often said, we can't predict the weather a week in advance, how could we be so foolish as to think we can project the climate a hundred years in advance? But it's a very different sort of calculation, so they're trying to do different things - that's the bottom line.

DAVIES: You know, one reason I as is that I read that a study of meteorologists - particularly TV weather meteorologists - found that there's a lot of skepticism among - about climate change. Fewer than half of them think that warming is occurring. Does this make any sense to you?

LEMONICK: Well, I mean it does make sense, because these are folks who are very focused on those weather models. They're very focused on specific prediction. They don't tend to think much about much different sort of prediction that goes into climatology. They are very, very well-educated on what they do, but not on climatology, which is related but a very different thing.

DAVIES: Let's talk about what some of the impacts will be in the coming decades or potential impacts. Displacement of human population - if, for example, if the sea rises up two, three feet, what might we see?

LEMONICK: Well, we'll certainly see low-lying places like - Bangladesh is often quoted because it's a low-lying country. Island countries like the Maldives Island will be very threatened. Again, not just by the rising of seas, but by the storm-driven floods that come along quite frequently and that will drive the sea much further inland. In a place like Bangladesh, especially, it's river delta country, there are a number of river deltas there. And so when water tries to flow into the sea from the mountains, the Himalayas or wherever it comes from, that water is trying to enter a higher sea. It has a harder time draining into the sea when the sea is higher. So that combination will cause enormous amounts of flooding. It will displace people in the - probably in the millions - but nobody knows exactly how many people because they can't really predict how far people are going to move, how adaptable people are going to be, to the flooding. So estimates of displacement of human populations are really pretty loose and pretty vague. We do know that people will be very badly affected, whether they'll move away, it's not certain.

DAVIES: Growing seasons are already lengthening? Is that right?

LEMONICK: Growing seasons are already lengthening. They've lengthened by a couple of weeks - at least in the U.S., so far, and that's likely to continue.

DAVIES: And some people might say that's a good thing, isn't it? I mean...

LEMONICK: Yeah. Sure. If the growing season were to get longer and all else remained equal, that would be a good thing. I think this is true. I remember reading about the fact that in Alaska they grow gigantic cabbages because the growing season is relatively short, but the sun's up 24 hours a day so the cabbages go wild. But changing just one factor of the climate and holding all the others constant might be a good thing. The problem is that other things are changing as well. We are getting more droughts. You look at the corn crop in the U.S. this year, the fact the growing season is longer is not helping out a great deal in the midst of this terrible drought.

DAVIES: Are we seeing visible effects on animal populations of global warming already?

LEMONICK: We are seeing effects on animal populations in subtle ways, but they're getting less subtle. One thing that's kind of striking, you know, we talk about ecosystems, you know, the whole ecosystem is going to have to move north as the climate gets warmer to look for comfortable temperatures. But what biologists are seeing is that an ecosystem is composed of many, many species, and those species react differently to climate change. Some are more resilient, some are less resilient, and there have been a number of studies - for example - that show that migrating birds are being affected in a kind of a surprising way, which is to say they migrate partly to keep time with the changes in species, the flowering of plants or the emergence of butterflies or whatever, in the place that they migrate to.

And there was a study a couple years ago - I believe in the Netherlands or somewhere in Europe - where birds were arriving from Africa, ready to feast on the larvae of certain butterflies, but the larvae had already come out two weeks earlier, and they'd all flown away, and there was nothing for the birds to eat. So the timing of these life events, migrations, and egg laying, and flowering and so on are changing, but they're changing at different rates. And that makes an ecosystem that has evolved in a cooperative way over the last couple thousand, or 10,000, or 100,000 years - it throws it out of kilter. So, yes, we are seeing significant effects.

DAVIES: We use a lot of fresh water. I mean the growing population of the Earth. What will the impact of climate change be on the availability of potable water?

LEMONICK: There's a lot of evidence that there will be a negative effect on potable water - on fresh water. One reason is that the snowmelt that comes down from the Himalayas and the Sierras and the Andes, and the other great mountain ranges of the world, and waters of the lowlands throughout the summer is melting earlier. So the streams fill up with water in the spring and they rush with the, you know, babbling brooks and so on, but then they run out. And they run out earlier in the summer than they used to and that means that there is the water is no longer available, it's gone.

Another problem is that we are going to see increasing droughts and that people will have to depend more and more on water from aquifers, if they're there - and as we pump the aquifers dry, that water is no longer available, or they'll get the same amount of water over the year but it'll come in floods and then dry periods in between. And when torrential rains come down and the water floods across the landscape and then it's gone, you don't have the access to it. So fresh water supplies are likely to be a real problem in a warming world.

DAVIES: The book also mentioned some effects not so widely discussed - potential effects of climate change - like infectious diseases. How might they be impacted?

LEMONICK: Many infectious diseases are carried by vectors - animals, insects, mosquitoes, flies and so on. And those animals live at a certain range - and the insects live in a certain range - they thrive in a certain range of conditions. And as the climate changes, their comfortable habitat is also likely to change, and it's likely that at least some of these will invade areas where they were formally rare.

And this is one of these instances where you have to be careful about not ascribing everything to climate change. Climate change will have an effect on the distribution of disease-carrying mosquitoes, for example, but it's also important to realize that malaria, which we think of as a tropical disease, was actually endemic in large parts of the U.S., including Philadelphia, including New Jersey, up until about 1900, and widespread swamp drainage and mosquito eradication programs have helped to eliminate it. So the public health infrastructure in any given place is a big factor in whether these disease outbreaks will actually be severe or not. Climate change will just be one more factor pushing toward more disease outbreaks, it's not the only one.

DAVIES: We're speaking with Michael Lemonick. His book, along with Emily Elert is called "Global Weirdness." More after a break.

This is FRESH AIR.

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DAVIES: If you're just joining us, our guest is science writer Michael Lemonick. He is the author with Emily Elert of the new book "Global Weirdness." It's the product of the group Climate Central. It's a non-profit organization of scientists and journalists which studies climate change.

There's a section in the book where you write about what can be done about this. And because I think your organization and the book is so careful, you know, not to paint in broad strokes, and to include all the caveats that might come within the analysis, none of the alternatives seem terribly workable, effective or likely. How do you help people and policymakers make the right choices here?

Well, that's, you know, that's a problem. You know, on one hand you don't want to be a doomsday prophet and say look, nothing is going to work. It's all downhill from here. We're just in trouble. On the other hand, you want to be realistic and say that since I started writing about climate change, all the way back in 1987, we've known what the cause is, we've known what the likely outcome is, and we've had time to act. And essentially, we haven't acted. And so, you might be tempted to be pessimistic.

LEMONICK: What I guess I'm trying to do with this book is to raise the general level of consciousness and understanding about climate change to a degree that policymakers who actually have to make laws and regulations - because without government intervention it's going to be very difficult to do anything about this, it has to be done on that large a scale - to make them feel emboldened to be able to take these actions and not to worry about sniping from individual senators or politicians who call it a hoax and, you know, talking kind of nonsense about it. And the analogy I use is the one with smoking. So if, in 1964, when the Surgeon General came out with his first report on smoking and cancer, politicians had immediately tried to pass laws banning smoking in restaurants and in public places and in hotels and on planes, there would've been an outcry, people would've been outraged at that infringement on their rights.

It would've been inconceivable to do such a thing. And after a number of years of education campaigns and more research and a growing public understanding that smoking is indeed really bad for you, and really bad for other people, those laws were passed without even a whisper of objection. And so if somebody lit up a cigarette on a plane I would be shocked. And what happened is that, essentially, smoking in public became socially unacceptable in a large parts of the U.S. And the hope is that emitting carbon and other and other greenhouse gases, carbon dioxide, will become socially unacceptable and will give politicians a space to say well, of course, you know, we need to raise fuel standards on cars; of course, we need to limit emissions from coal-fired power plants and from cars and so on. We need to pass laws that make it expensive to emit carbon and force people to look for other alternatives.

DAVIES: I may be wrong about this, but it's my impression that, you know, public opinion survey show that there's less belief in, you know, human cause of climate change and there was, you know, pick a point, 10 years ago. Is that the case?

LEMONICK: Different surveys come to different conclusions about that. I take all that a bit with a grain of salt. There is also a - there are also surveys that show that half of Americans don't believe in evolution. And I guess there are, I guess people are answering questions and saying that. I don't think the survey people are lying about it, but if America were truly that ignorant about science in a fundamental way, we would be a far more backward country than we are. So, yeah, I guess some surveys say that - but I don't think politicians really are worried about those surveys so much. I think that if there is a general sense - I don't think they look at surveys that say OK, now we can ban smoking in restaurants. If there were a general agreement in society that climate change is something we want to avoid, I think it would be apparent without surveys and so I don't worry so much about that.

DAVIES: If we are able to significantly reduce Greenhouse gas emissions, what does the science tell us about how long the effects will be of what's already been released?

LEMONICK: Ah, yes. Well, that's the thing about carbon dioxide. So it is naturally removed from the atmosphere by all sorts of natural processes and always has been, and that's why it's always been in balance - why it's been in balance for the last several thousand years - 10,000 years or so. And we've started adding carbon dioxide, but we haven't added any new mechanisms to remove it. So it has been building up, and the natural forces that remove it from the atmosphere are going at their own normal steady pace.

The result being that the carbon dioxide that we've put into the atmosphere so far is mostly still up there. And it will stay up there for a long, long time.

So it could be up there warming - in fact, it will be up there warming the earth for many, many hundreds of years to come. The bad news is that if we were to cut back on emissions drastically today - which we're not doing - we've already built more warming into the system and, sort of, a continuous warming that will go on for a long, long time.

DAVIES: So does that suggest there's going to have to be some big geo-engineering to try and ameliorate those effects?

LEMONICK: Well, geo-engineering is a broad term that covers a lot of different things. The only scheme in geo-engineering that would fall into what you're talking about is some sort of device, some sort of technology that would literally scrub CO2 out of the air, draw it out of the air and bury it somewhere. That doesn't exist.

People are working on it. People think that maybe they can figure out how to do it but we're long from any such technology. Geo-engineering is also used to describe schemes to reflect sunlight back out into space and so keep the temperature from rising any higher. And there is active discussion about that.

The most straightforward idea is to create artificial volcanoes minus the lava and the explosions. But pump particles into the air, the same kind that volcanoes pump, and use those to shield the planet and to keep it from warming up.

Very few experiments have been done with that, almost no experiments. Very few experiments are planned. People are worried about the possible risks. So it's an idea. It's something that people probably should be exploring - they should be exploring - but that's also a long way from being deployed.

I guess the thing is that if we reach a crisis and people understand that it's a crisis, we will try everything that we can possibly think of and geo-engineering is one of those things.

DAVIES: You know, you were saying a moment ago that, you know, attitudes changed about smoking over the decades both because there was new science about the health affects but also because people saw it around them. They had friends who got cancer and other illnesses. What's going to make people take climate change more seriously?

LEMONICK: Well, I think that people are seeing the effects of climate change around them more and more already. They're seeing flowers bloom earlier in the spring. They're seeing changes in the landscape around them. But they're also seeing things like this terrible drought we're having this summer. We're seeing the heat waves we had earlier this summer, record heat. In fact, it's still going on in parts of California.

It is dangerous to say, and it's scientifically incorrect to say, yes, this is climate change; nothing else is going on here because many things are always going on. But the kinds of conditions we are seeing this summer in the U.S., the kind of conditions we saw last winter in the U.S. with a very unusually warm winter in most of the country, are the hallmarks of climate change.

And these are the kinds of conditions that we will see more and more often as the century progresses. So I think it's perfectly valid to say to people, look around you. Look at what this weather is like and imagine it's routine. It's not a rare occurrence. That is climate change. That is what's coming.

If you like this really unpleasant weather, then don't worry about it. Just - it's coming. If you don't like it, you better start thinking about doing something.

DAVIES: Well, Michael Lemonick, thanks so much.

LEMONICK: Thank you.

DAVIES: Michael Lemonick is the co-author of "Global Weirdness: A Guide to the Science of Climate Change" from the group Climate Central, an independent group of journalists and scientists. You can read an excerpt on our website freshair.npr.org. Lemonick also has a forthcoming book called "Mirror Earth" about scientific efforts to find a planet similar to our own.

Coming up, linguist Geoff Nunberg considers the meaning and political implications of the words entitlement and entitlements. This is FRESH AIR.

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DAVE DAVIES, HOST: Mitt Romney's choice of Congressman Paul Ryan as his running mate suggests a major focus of the fall campaign will be on fiscal issues, particularly on the cost of programs called entitlements. But as our linguist Geoff Nunberg points out, that word carries a lot of social and political baggage.

GEOFF NUNBERG: People are saying that Mitt Romney's selection of Congressman Paul Ryan as his running mate creates an opportunity to hold what Ryan likes to call an adult conversation about entitlement spending. In the present political climate, it would be heartening to have an adult conversation about anything.

But it helps to bear in mind that the word entitlement doesn't put all its cards on the table. Like a lot of political language, it can enable you to slip from one idea to another without ever letting on that you've changed the subject.

Entitlement originally had two separate meanings, which entered the language along very different paths. One sense of the word was an obscure political legalism until the advent of the Great Society programs that some economists called uncontrollables. Technically, entitlements are just programs that provide benefits that aren't subject to budgetary discretion.

But the word also implied that the recipients had a moral right to the benefits. As LBJ said in justifying Medicare: By God, you can't treat grandma that way. She's entitled to it. The negative connotations of the word arose in a very distant corner of the language, when psychologists began to use a different notion of entitlement as a diagnostic for narcissism.

Both those words entered everyday usage in the late 1970s, with a big boost from Christopher Lasch's 1979 best-seller "The Culture of Narcissism", an indictment of the pathological self-absorption of American life. By the early '80s, you no longer had to preface sense of entitlement with unwarranted or bloated. That was implicit in the word entitlement itself, which had become the epithet of choice whenever you wanted to scold a group like the Baby Boomers for their superficiality and selfishness.

Granted, these polemics belong to an ancient genre. People may not have talked about entitlement as such before the Boomers and Generation X. But critics were saying similar things about the generations of the '50s, of the '20s, of the 1890s, and so on back to Generations A and B. It's hard to think of any age when people weren't saying: Kids today, I'm here to tell you.

Still, entitled isn't quite the same as time-honored reproaches like spoiled. Like narcissistic, entitled adds a tone of clinical authority. If you want to know if someone is spoiled, you ask your grandmother; if you want to know if they've got a sense of entitlement, you ask Dr. Joyce.

And while spoiled suggests someone at the mercy of infantile needs, a sense of entitlement implies a legal or moral claim. When you give a kid who's spoiled a B-minus on his final, he comes to your office hours and throws a tantrum about how he needs an A to get into medical school. When you give the same grade to a kid with a sense of entitlement, you're apt to get a call from the family lawyer.

The two words spread the blame around differently, too. Spoiling begins and ends at home. But while parents are blamed for creating entitled children, critics of the entitlement epidemic find lots of other culprits for it - from the media-fed obsession with celebrity to schools that over-praise their pupils, feminism, affirmative action, plastic surgery, cheap credit cards and Wikipedia.

But it's only when critics get to the role of government that the two meanings of entitlement start to seep into each other. On the one hand, the psychological sense of the word colors its governmental meaning. When people fulminate about the cost of government entitlements these days, there's often the implicit modifier, unearned, lurking in the background.

And that in turn makes it easier to think of those programs as the cause of a wider social malaise - that they create what critics call a culture of dependency or a class of takers, both of them ways of referring to what the Victorians called the undeserving poor.

This isn't a new argument. The early opponents of Social Security charged that it would discourage individual thrift and reduce Americans to the level of Europeans. But now the language itself helps make the argument, by using the same word for the political cause and the cultural effect.

You can deplore the entitlement society without actually having to say whether you mean the social or political sense of the word, or even acknowledging that there's any difference between them. It's a strategic rewriting of linguistic history, as if we call the benefits entitlements simply because people feel entitled.

But to make that linguistic fusion work, you have to bend both meanings of the words to fit. When people rail about the cost of government entitlements, they're thinking of social benefits like Medicare, not the price supports or the tax breaks that some economists call hidden entitlements.

And what people call the culture of entitlement is elastic enough to include both the high-school senior who's been told he has a right to get into Harvard and the out-of-work plumber who isn't bothering to look for a job because he knows his unemployment check is in the mail. But it rarely stretches to include the hedge-fund manager who makes a life model of Ayn Rand's Howard Roark, who's actually the most conspicuous monster of entitlement in all of modern American literature.

No question, it would be useful to have an adult conversation about entitlement and entitlements. Not that politicians or pundits are about to abandon the words or the semantic sleight-of-hand that's built into them. But with more people paying closer attention, those moves may be a little harder to get away with.

DAVIES: Geoffrey Nunberg is a linguist who teaches at Berkeley School of Information. His new book "Ascent of the A Word" will be published this week.

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