MS. DIANE REHMThanks for joining us. I'm Diane Rehm. In an attempt to deal with global climate change, some scientists have given up trying to reduce greenhouse gases. Instead, they're turning to new technologies that can manipulate the Earth's weather and temperature. An Australian expert on global warming has a new book that explores this growing field called geoengineering. It's titled, "Earthmasters," and author Clive Hamilton joins me. We'll welcome your questions, comments. Call us on 800-433-8850.

MS. DIANE REHMSend your email to drshow@wamu.org. Follow us on Facebook or Twitter. Welcome to you, sir. Good to have you here.

MR. CLIVE HAMILTONGood to be here.

REHMAnd I am fascinated, Clive Hamilton. You are a Professor of Philosophy and Ethics, and yet, here you are writing about geoengineering. First, explain geoengineering, and then tell us why, as a philosopher, you are interested.

HAMILTONWell, geoengineering is a range of technologies that aim at deliberate, large scale intervention in the climate system, designed to counter the effects of global warming, or to offset the warming itself, usually divided into two types. Carbon dioxide removal technologies to get carbon dioxide out of the atmosphere one way or another and so-called solar radiation management, a kind of Orwellian terms which amounts to trying to reduce the amount of sunlight or solar radiation, which reaches planet Earth.

HAMILTONWe can talk a bit more about...

REHMSure.

HAMILTONHow that can be done later. But why, as a philosopher? Well, it seems to me that climate change, global warming is transforming the Earth as a system. It's not just the climate. The climate scientists are telling us that global warming, because of the deep interactions of the Earth's system, is changing the nature of the oceans, is changing the biosphere, the living conditions. It's the whole Earth system itself. So, if you think about it, here we are at the beginning of the 21st century, where in the 4.5 billion year history of planet Earth, we have human beings and their activities transforming the total functioning of the Earth's system as a whole.

HAMILTONIt seems to me this is the most profound event, that's not just in human history, but certainly a deeply profound event in the history of planet Earth itself. So, it has very profound philosophical implications.

REHMAnd now, talk about how geoengineering might take place, or is taking place.

HAMILTONWell, it's not being practiced at the moment, but certainly, some very imminent scientists, with the best of motives, are talking about the need to develop what they call Plan B. Plan A, reducing global greenhouse gas emissions, obviously isn't working, so shouldn't we need Plan B? Particularly if we are confronted, in the next, say 20, 30 years with what they call a climate emergency. Some imminent, dramatic change, irreversible change in the Earth's climate system that we know is about to happen, and which we need, somehow, to stop, because once we pass that point of no return, it will be game over.

REHMGive me an example of what that might be.

HAMILTONOf that kind of climate emergency?

REHMYes.

HAMILTONIt might be, for example, the collapse of the Amazon Rainforest. It may be, for example, I mean, once that goes, that vast, you know, they call it the lungs of the Earth, through fires and dieback, on a warming globe, it may well be impossible to bring back the Amazon. Or, another more immediate concern is a massive release of methane, which is currently trapped in the frozen tundra of Siberia and northern Canada. If that starts to leak out, because the Earth starts to warm, and starts to leak out on a massive scale, bearing in mind that methane's a very powerful greenhouse gas.

HAMILTONIf that starts to leak out, and in fact, it already is, on a small scale, but if it starts to leak out on a very large scale, putting a huge emission of methane into the atmosphere, then we're going to be in very, very serious trouble. So, the climate scientists say, well, what can we do to prevent that? And there are a range of schemes, 40 or 50 that have been put forward. Perhaps six or eight are receiving serious attention. Only carbon dioxide removal side of things -- there are various schemes for sucking carbon dioxide out of the atmosphere through using basic industrial technology.

HAMILTONAnd then trying to bury that carbon dioxide deep under the ground, if spaces can be found for it.

REHMOr even in the ocean.

HAMILTONIn the ocean, because the oceans contain a very large amount of carbon dioxide, particularly in the deep ocean. So there are a number of schemes designed to try to get carbon dioxide out of the atmosphere and into the deep ocean. And the most prominent one, which has received a lot of attention, quite a lot of experiments have been carried out, is known as ocean iron fertilization. And it works like this. Slightly complicated, but let me see if I can do it in a simple way. There is, what's known in the ocean, as the biological pump.

HAMILTONAnd this is a way in which carbon dioxide is pumped down to the deep ocean through the intervention of tiny marine creatures called phytoplankton or algae. And the idea is if we can stimulate the growth of these algae, by creating artificial algal blooms, then these tiny algae, because they're living creatures, will absorb carbon dioxide in the surface waters of the ocean, and when they die, they'll take their carbon down to the bottom of the ocean where it is hoped it will be stored permanently.

HAMILTONSo, how do we get the algae to grow more than they naturally are? Well, to add micronutrients. If we can find a patch of ocean where there's some missing nutrient, you know, it's like your garden, if you don't have enough phosphate, you add phosphate and up come the plants. In the ocean, a missing nutrient, it's thought, is iron. So, if we add iron to certain patches of the ocean, then we'll get these great algal blooms, and then they will capture carbon and then eventually take it to the bottom of the ocean.

REHMBut, of course, then the question might arise, what happens to marine life as a result of adding more of this iron and then carbon dioxide?

HAMILTONWell, of course, anyone who knows the first thing about ecology is that if you do one thing, a whole lot of other things will happen.

REHMExactly.

HAMILTONIt's a complex system, and so those scientists who are studying ocean iron fertilization have started to realize that it's very complex. And all sorts of things happen. That the phytoplankton get caught up in the food cycle of marine organisms, that a lot of them get eaten, that a lot of it gets emitted back into the atmosphere. That the algae, when they grow, they suck nutrients from surrounding patches of the ocean. So the amount of algae in other parts of the ocean declines, so you don't get any...

REHMSo any action has another action, and a reaction.

HAMILTONIndeed. And so, that's why the initial enthusiasm for ocean iron fertilization has been dulled a little bit. Because the early results coming in don't give the kind of positive stimulus that these scientists had hoped. That hasn't stopped a lot of people continuing to pursue it, including some rogue entrepreneurs who are out there trying to create carbon credits by spreading iron in the world's oceans. Bear in mind that if this were to be done on a very large scale, we would effectively be changing the biological composition of the world's oceans.

HAMILTONI mean, this is a very radical and dangerous thing.

REHMI should say. And then, you talked about somehow diminishing the amount of sunlight coming through. How are some scientists thinking about that?

HAMILTONWell, a number of proposals have been put forward. One is painting our roofs white so more sunlight is reflected. Which, in itself, isn't a bad idea. It will certainly make your house a little bit cooler, but we don't have enough roofs or roadways or whatever to make any significant difference. Another kind of science fiction suggestion is to shoot a very large number small mirrors into the atmosphere and position them so that they deflect a certain amount of sunlight before it reaches the Earth. This is kind of a bit of, as I say, sci-fi.

HAMILTONAnd no one's seriously putting it forward. But the most important proposal, and one which is receiving very serious attention, a lot of research around the world, and which has been actively advocated by some scientists, and which, I should say, Diane, in my view, is quite likely to actually be implemented, despite all of its dangers, is a proposal known as sulfate aerosol spraying. And the idea is to send up a fleet of aircraft. Well, they'd be up there, more or less, permanently, and they would spray sulfuric acid out of the backs of the aircraft.

REHMSulfuric acid?

HAMILTONSulfuric acid. Yes. Or possibly sulfur dioxide. And this sulfur chemical would form into tiny aerosols, very tiny particulates, up in the upper atmosphere, in the stratosphere, and you'd put a very sort of thin layer of pollution, effectively, in the upper atmosphere. And that way, you would dim the Earth. You could adjust it so you would reduce the amount of solar radiation reaching the Earth by maybe one or two percent. And it's been estimated that if it were reduced by two percent, that would be enough to offset the warming that the Earth is experiencing and is likely to experience in the next 20 or 30 years.

HAMILTONClive Hamilton. Professor of Philosophy and Ethics at the University in Canberra, Australia. His new book is titled, "Earthmasters." Short break here. We'll be right back.

REHMIf you've just joined us, Clive Hamilton is with me. He's professor of philosophy and ethics at the Charles Stuart University in Canberra, Australia. He's written several books on climate change. His newest titled "Earthmasters: The Dawn of the Age of Climate Engineering." And just before the break you were talking about the spreading of sulfuric something or other in the stratosphere as a way of creating kind of a shadow that would filter or reduce the amount of sunlight coming through to the earth.

REHMI'm not sure I want to live through that, Clive Hamilton.

DR. CLIVE HAMILTONWell, there're very serious and imminent scientists saying that this is what we're going to need to do. So you have to take it seriously.

REHMBut what about the effects on human beings?

HAMILTONWell, the thing is that we already -- when we burn coal and petro we put a lot of sulfuric compounds into the lower atmosphere. And we know in a place like China, for example, that kills large numbers of people every year in the United States because of antipollution laws, the situation isn't nearly as bad.

HAMILTONAnd so putting the sulfuric acid or sulfide oxide into the upper atmosphere would -- actually the amount would be substantially less than is already in the lower atmosphere. But no less, enough would be put in there and would circulate around the globe to reduce the temperature of the earth by however much we liked. I mean, it would depend on who had their hand on the global thermostat, which gets to all sorts of other issues I'm sure we'll come to.

HAMILTONBut the idea for sulfide aerosol spraying was stimulated by observations by scientists on the impact of major volcanic eruptions on the earth's climate system. It's been known for quite a long time that big volcanic eruptions put so much sulfur compounds and dusts and ash into the atmosphere that they do dim the earth and actually can cool it quite dramatically by one degree or even one-half degree for a couple of years.

HAMILTONAnd so there've been some very big volcanic eruptions in the past. I mean, even Mount Pinatubo in the Philippines in 1991 had a major impact on the global weather system for a couple of years. And so the idea is to mimic the effects of volcanic eruptions by coating the earth with these sulfur particles. And, I mean, there are all sorts of implications. Again, it's like the ocean ion fertilization. As soon as you talk about it, you say yes but what about. And there are so many what abouts to talk about.

HAMILTONI mean, one is it's thought that the sulfur compounds would damage the ozone layer, which we know the world is starting to repair after the so-called Montreal protocol, while the sulfur compounds, the sulfate aerosol spraying would delay the repair of the ozone layer by perhaps 50 years or so. Another very serious concern is although this technique would almost certainly cool the earth, it would also change precipitation patterns. It would change the way rainfall occurs around the world.

HAMILTONAnd one of the concerns is that it may have an impact on the Indian monsoon. It may shift it from India across to northern Africa. And if that happened, of course you're affecting the food supply for a billion people. And so you could imagine if this program was launched, you know, sulfide aerosol spraying by the United States or by China or by perhaps Russia -- any even middle-sized power could do it, and incidentally, there's no international law to stop them from doing it.

HAMILTONBut if one country or a couple of countries did embark on this gain and there is a big drought and starvation in India, then of course the Indians would have something to say about it because even if it weren't actually caused by the sulfate aerosol spraying, it could be caused by global warming itself. It could be caused by natural variability. But if the United States or China had its -- were turning down the global thermostat, then India of course would be very angry about it.

REHMYou and I both started this conversation by saying that reducing greenhouse gases is not working. And yet, as you just said, the ozone layer seems to be repairing itself. How is that happening?

HAMILTONWell, the ozone layer was being destroyed by the emission of so-called CFCs, chlorofluorocarbons, a bunch of highly specialized gases that we used in refrigerators and so on. And when it became apparent that the ozone layer had a hole in it, in other words was thinning, and that a lot more ultraviolet radiation was getting through, which causes all sorts of problems including cancers, the world got together at Montreal in 1988, I think it was, and reached an agreement where the CFCs would be banned.

HAMILTONIt took -- you know, over a period of 10 or 15 years though it phased out. And it was relatively easy because a couple of reasons. One is, rich white people were going to be most affected by the hole in the ozone layer. And secondly, there were reasonably available substitutes for these particular chemicals. And so there was a global agreement to phase them out fairly quickly. And the ozone layer hole is starting to be repaired.

HAMILTONOf course, you think, well, if we could do it for CFCs, why can't we do it for greenhouse gases? And it turns out it's a lot more complicated of course. You think about the role of fossil fuels in our economy. They really are very fundamental. The fossil fuel corporations like Exxon Mobil are extremely powerful. And there's a lot of political ideological resistance to the idea of reducing greenhouse gas emissions. You know, a lot of it concentrated in this town where we're speaking today.

HAMILTONAnd so for those reasons, the world major powers have been extremely reluctant to do the -- implement the kinds of policies that the sides of climate change demands.

REHMSo here's a basic statement from Claude in Stewartstown, Penn. Let's see your thoughts on this. He says, "Global warming is a fact. Geoengineering is an untested science, and from my perspective, very, very dangerous. It would seem that a safer and more effective means of carbon sequestering would be to replant the earth's rain forests. And this would have the added effect of increasing the availability of renewable wood for any number of uses.

HAMILTONWell, that makes a great deal of sense. And when you look at the amount of forestation and deforestation going on in the world today -- of course, there's a lot of tropical deforestation going on -- but there's also a lot of trees coming back in various other parts of the world. And the best estimates are that they're about balancing each other out. Nevertheless, historically human beings have cleared vast amounts of the landscape of trees. And it would make a lot of sense to start putting them back. The fact is, however, that we can't grow enough trees to take a major portion of the carbon dioxide out of the atmosphere.

HAMILTONThe way I think about it is this. What we're doing here, what humans have been doing over the last couple hundred years, but particularly over the last 50 to 70 years, is digging down into the earth where we've found highly concentrated forms of carbon as coal and oil and less (word?) natural gas. And we've been digging it up, burning it, extracting the energy and putting the carbon as carbon dioxide into the atmosphere. And so we need to get it out. First of all we need to stop doing it and then we need to get it out.

HAMILTONAnd growing trees is one way of doing it because trees absorb carbon dioxide as they grow. And that's certainly a good thing. But there just aren't enough trees to be grown to really compensate for the digging up of all that coal, oil and gas.

REHMAnd here's a question from Lloyd in Winterville, N.C. "As an effaces, do you see the moral hazard of geoengineering and can you talk more about this?"

HAMILTONWell, this is perhaps one of the greatest political concerns about geoengineering as opposed to the scientific risks associated with the various games. And that is, if there is a plan B, will that not undermine the incentives to pursue plan A, that is reduce greenhouse gas emissions? And this is certainly my -- one of my greatest concerns. You can imagine how politicians who are reluctant to pursue emission reduction policies, even though all of the best advice is saying we must do this.

HAMILTONIf someone comes along, some scientist said, hey you don't have to take all of that political risk. You don't have to take on the fossil fuel corporations. You don't have to put a tax on gasoline. We've got this techno fix that'll allow you to avoid all of that political pain. And although talking about geoengineering is at the moment a political taboo, I think the time will come when some politicians will say, hey I like the sound of this. If you scientists tell me this is going to work, I'm going to do that rather than try to put a tax on power stations or gasoline.

REHMAnd where is the moral hazard?

HAMILTONWell, the moral hazard is a term that's used to describe exactly this process. The way in which the availability of an apparently effective alternative undermines the incentive to do the right thing, that is reduce greenhouse gas emissions. So it's kind of a way out -- a cheap way out of a difficult situation that politicians, I think, are likely to seize upon, which is why my assessment -- reluctant assessment is that sulfate aerosol spraying is something that the world is very likely to do in the next 20 or 30 years.

REHMAnd as a philosopher, how would you feel about that?

HAMILTONWell, I mean, what it means is that human beings, for the first time in our history, will attempt to take control of the earth's system in its entirety. Not just a certain part of the environment, not a piece of landscape or river system or a bay, but the earth's system as a whole. And we will -- if we do this we will say, okay, let's start pushing around. We're just going to take the whole thing on. We will use our technology to regulate the earth as a whole and do it probably in perpetuity. To me this has very profound implications. There will be no more natural.

REHMAnd you're listening to "The Diane Rehm Show." Here's a Tweet from Evan. "Is there any evidence of an ocean fertilization effect from micro plastic pollution? Could this be a silver lining to pollution?"

HAMILTONI'd love to think it was. I haven't seen any research or evidence suggesting that there's any benefit to the enormous amounts of plastics now floating around in the oceans, which has led some marine scientists to refer to the oceans now as a plastic soup.

REHMAll right. We're going to open the phones. We've got many callers waiting. First to Tulsa, Okla. Hi, Scott. You're on the air.

SCOTTGood morning, Diane.

REHMHi.

SCOTTI'm really glad that you let me on here. It's a clear day here in Tulsa. There's no contrails in the sky. I wanted to speak on the fact that you guys are talking about this as a future possibility. These things have been up in the sky for -- since the '70s. I've talked to older gentlemen that have seen these things. It's been going on for a long time. And...

REHMSeen what things, Scott?

SCOTTThe trails that you see in the sky, they're called persistent contrails. And there's no sulfur in them. It's actually nano particles of aluminum, barium and some other metals. And I understand that reflecting the sunlight, that's what they're supposed to do. But what it does to humans, what it does to plants, it raises the ph level in the plants. Things can't grow, you know.

REHMAll right. Let's see what Clive has to say.

HAMILTONWell, you know, this is the chemtrail conspiracy that some folks seem to believe in. But -- and, you know, I've heard it talked about a lot. It's all over the internet. And, in fact, the chemtrails people have kind of annexed the term geoengineering quite wrongly in my view. But I've asked some cloud physicists and atmospheric scientists what they think about this, whether there's any evidence for this chemtrail so-called. And none of them can detect any evidence whatsoever for these kinds of claims.

HAMILTONIf you look in the scientific literature and the peer review journals, there's no serious scientist give any credence whatever to this chemtrail stuff. So really it's a conspiracy theory, a bit like the global warming hoax conspiracy theory.

REHMAll right. To Michael in Charleston, S.C. You're on the air.

MICHAELDiane, first I want to thank you for your service and all of the fine years that you have spent trying to bring consciousness of several different problems that...

REHMThank you.

MICHAELAnd second, I'm involved very deeply right now with (word?) mining and very seriously. And one of the bi-products of (word?) mining would be the possibility of building an earth shield in space. It may seem farfetched science fiction and all that, but in fact it isn't. And I applaud your guest's efforts to try to control and mitigate the problems of global warming as a whole on the planet. However, it seems to me that all the solutions that are being proposed are one-way solutions. In other words, the question is, do you really have a fallback position in case something goes wrong, which, you know, Murphy lives out there.

REHMAll right. And I thank you for your call. We've got to take a short break here. When we come back, Clive Hamilton, I hope you'll address that issue. 800-433-8850. Short break, right back.

REHMAnd welcome back. Clive Hamilton is with me. His new book is titled, "Earthmasters: The Dawn of the Age of Climate Engineering." And just before the break, our caller asked a question. I think you made note of it, Clive.

HAMILTONYes. I think this question, from Michael, was, he talked about an Earth shield, an asteroid...

REHMRight.

HAMILTONI don't know anything about that. It does sound kind of sci-fi, but I think one of the things he was getting at was, what happens when things go wrong? And I just wanted to talk about one of the problems with sulfate aerosol spraying, which kind of goes to the heart of the whole enterprise of human arrogance and our belief that we could take control of the Earth's climate system. And the problem is this. That if we were to install this solar shield and dim the Earth by a little bit to reduce, to cool it down, it turns out that we would -- there's a lot going on in the climate system.

HAMILTONAnd so we would need to have this solar shield installed for at least 10 years before we had enough data coming in from all of our measurements of what's going on before we knew whether it was working. And so, we would need it up there for 10 or maybe 20 years, gathering data, to be able to separate out the effects of the solar shield from the effects of global warming itself and the natural variability. And the trouble is, let's say we put it up for 10 years or 15 years, and then we decide, this is a really bad idea, because there are some unintended consequences.

HAMILTONOr perhaps because India is saying, we don't like it. Take it down, and by the way, we have nuclear weapons. If we did take it down, then all of the warming that was suppressed by this solar shield would come back very suddenly, and so we could get a surge of global warming, which could make things worse. Because it's the rate of warming, as well as the amount of warming that really damages ecosystems.

REHMAnd what about solar power? What about the effects on solar power if you did go to lengths to dim the amount of sunlight coming through?

HAMILTONWell, that would be one of the consequences. If you, essentially, turn down the sunlight, then yes, solar power, which depends on it, would be reduced by a similar amount. In addition, certain plants would be affected by the reduced amount of sunlight. It turns out that some plants would actually benefit from it, because they prefer a dimmer environment. But other plants would suffer, because they grow best when there's a lot of bright sunlight, so...

REHMAre solar power and wind power on the right track?

HAMILTONDefinitely. I think there's no question that the world will make, will have to make, sooner or later, an enormous transition to renewable energy. And solar and wind power will be at the forefront of that. And one of the fascinating things going on is that while nations, such as the United States and Australia prevaricate, China is seizing the opportunity to become the world leader in these renewable energy technologies. So now we're seeing that China is flooding the world with very cheap solar panels.

HAMILTONAnd those countries which also want to be in that game are complaining, because the Chinese are doing it too cheaply. And so, there's this interesting dynamic going on about an industrial transition, which certain countries, like China, are realizing is going to be very big. And other countries are resisting.

REHMWhat about Australia? Thomas, in Dallas, Texas says, conservative Australian politicians are advocating for turning off the carbon tax currently in place. What's your opinion of that?

HAMILTONWell, tragically, the Australian electorate voted in a conservative government some months ago, led by a man, Tony Abbott, who is famous, or infamous, for saying a few years ago, climate science is crap. He's an out and out climate denier, although he now has to pretend not to be. He's surrounded himself with people who believe global warming is a hoax, including the head of his business advisory council. And so we now have, in Australia, or a government where the climate denying wing of the conservative parties have been given their heads.

HAMILTONAnd so, it's a sort of great anguish for me, and others in Australia, who take climate science seriously. One of the measures that the new Abbott government is going to do is to abolish the carbon price, which Australia has had for the last couple of years.

REHMAnd what will that mean? Will it simply mean that more carbon is going to go in to the atmosphere?

HAMILTONYes. It will mean that measures to reduce Australia's greenhouse gas emissions are substantially diminished. It means that the alternative energy industries in Australia, which at last were getting some air to breathe, and to grow, are going to be confused and going to go backwards. I mean, it's a disastrous policy from every point of view. And it just shows you -- I mean, Australians voted for this government, a significant majority. They were tired of the previous labor government. And it shows you what happens when progressives screw up.

HAMILTONYou get conservatives in power. And they pursue these very reactionary kinds of policies that are really going to condemn the world to a hot and unpleasant future.

REHMAll right. To Laurie in Jacksonville, Florida. You're on the air. Laurie, are you there?

LAURIEHello?

REHMYes. Go right ahead.

LAURIEHi Mr. Hamilton.

HAMILTONHi there.

LAURIEMy very simplistic example of e=mc2, which turns energy into mass and mass into energy, is growing trees, which takes CO2.

HAMILTONYep.

LAURIEAnd then we use those for energy. Methane is a source of energy, which is a result of that process right up there. And my question really is, is how can we really manage climate change when you can't even predict it accurately? And I can see the future of some of this is lawsuits saying, you stole my rain. You stole my heat. You stole my cool. And when the majority of climate change in this world is the fact that the world tilts at 23 degrees, and we go around and (unintelligible) and, you know, apart and close. And that we are travelling around.

LAURIEI would say, we even have plate tectonics.

REHMOkay. All right. We're getting a little far off here. Go right ahead.

HAMILTONBut Laurie, Laurie's raised some very interesting points. I mean, one is that, talking about growing trees as a form of energy. And when you look at northern Europe and talk about renewable energy, there's a tremendous growth in very sophisticated forms of biomass energy generation. And so, in Scandinavia, for example, some of those nations have a very major part of their electricity generated by burning wood waste and other forms of waste. And so this is, as long as it's done in the right sort of way, a very effective form of renewable energy.

HAMILTONOne other point that Laurie made, that I think is very important. She talked about lawsuits. You stole my rain. And I think this is putting, in a very blunt way, what we could see if geoengineering is implemented. Because, as I mentioned before, one nation has its hand on the global thermostat and, let's face it, I mean, that nation is going to fiddle that knob so that it's climate system is benefits most, and other countries suffer as a result. If you can blame a country specifically for changing your weather in a bad way, then it's not going to be simply lawsuits.

HAMILTONIt's going to be serious global conflict.

REHMNow, you talked earlier about painting roofs white. Talk about the attempt to rescue the Peruvian glaciers by painting nearby mountains white.

HAMILTONYeah, this is a serious project that's been investigated in Peru. The glaciers are melting. Part of the problem is, as the glaciers melt, they expose the dark colored rock underneath. Dark colors absorb more warmth from the sun, and there's a kind of feedback process. So, the glaciers start to melt more quickly. So, some scientists are saying, well, if we get a kind of white slurry and we paint these rocks, these dark rocks white, then they will stay cool or not as warm. And this will slow down, and possibly even restore, the glaciers.

HAMILTONSo, again, this is a local level attempt, but it's -- you get a sense of how this whole process is working.

REHMYou know, what surprises me, as you talk about all this, and, of course, the limits of human understanding, is that geoengineering is getting major financial backing from the likes of Bill Gates and Richard Branson. How come?

HAMILTONWell, I mean, this is, when people hear about geoengineering, they think, oh, that's scientists just doing their crazy things. But when you look at who's backing it, financially and politically, geoengineering, you realize that this is a big deal that's not going to go away. So, Bill Gates, as you mentioned, is a substantial backer of research into geoengineering. He's an investor in a number of companies.

REHMSomething called Silver Lining. What's that all about?

HAMILTONWell, Silver Lining is a company which is pursuing a technology known as marine cloud brightening. And the idea is to send a fleet of unmanned special ships roaming the world's oceans, sending up a very fine spray of sea water into the low lying marine clouds, which cover a quarter or a third of the world's oceans. And if we can increase the extent and the whiteness of these marine clouds, then the idea is that they will reflect more sunlight back into space, and the earth will be cooler. So Bill Gates has an interest in that. He's also invested in a company called Carbon Engineering, which aims at air capture technology.

HAMILTONHe's an investor involved in a company called Intellectual Ventures, which is run by a man called Nathan Myhrvold, who was the Chief Technology Officer at Microsoft. And that company has patented what it calls a stratoshield, which is essentially a pipe, a tube, which is to be suspended several kilometers into the atmosphere, held up there by blimps, which would then spray sulfur dioxide into the atmosphere for this solar shield. They've taken out a patent on this. In fact, a lot of patents have been taken out by, particularly in the United States, but also in Europe and Britain, on these geoengineering technologies.

REHMAnd what about Richard Branson? What's he up to?

HAMILTONWell, Richard Branson, you know, has a kind of messiah complex, I think. Just quietly. He wants to save the world, and so he's created this thing called a carbon war room. You can Google it. And one of the things he's done is offer a very substantial prize to the inventor who can come up with the best geoengineering technology. But I think there's a -- and I think he's kind of, you know, off there, but a more interesting investor is a man called Murray Edwards. Now, Murray Edwards is a billionaire who made his money in tar sands in Alberta. The dirtiest form of fossil fuels, and of course, it's a huge debate in the US now about the pipeline and whether it's going to be piped through the United States.

HAMILTONMurray Edwards is an investor in carbon engineering. I mentioned, a moment ago, a company owned by David Keith, a Harvard physicist, who's an advocate of geoengineering. And so, when you look at these major investors in fossil fuels are dipping their toes into geoengineering, you have to get worried about the politics of that. I mean, we know that BP and Exxon and ConocoPhillips have started dipping their toes in the geoengineering waters a little bit, just to see where it's going.

HAMILTONAnd when these big companies start to get serious about geoengineering -- after all, the head of Exxon said, climate change is an engineering problem, and for it, we need engineering solutions. Then, I think we have to get very worried.

REHMSo, ultimately, I would assume, from what you've said, that you're pretty much against most, if not all, of these plans.

HAMILTONWell, look, as I said, there are some serious scientists like Paul Crutzen, who, the Nobel Prize winning atmospheric scientist, who won a Nobel Prize for his work on the hole in the ozone layer. In 2006, he wrote a very important paper saying, we have to consider Plan B. The situation is so bad. We're in such trouble, regrettably, we have to do work on Plan B. So, it's important to acknowledge that, and there's no questioning Paul Crutzen's environmental credentials. But I think, really, the question is, if we're going to pursue geoengineering research, who's going to control it?

HAMILTONWho's going to direct it? Who's going to fund it? Who's going to own the results? And this is where I'm very concerned that private investors and scientists pursuing this whole thing, in rich countries, and people in poor vulnerable countries, have no say. So, if it ever comes to a situation where, God forbid, these kinds of technologies are used, it should be done, it must be done, in a democratic way. If we're going to take control of the world's climate systems, then countries -- people in those poor and vulnerable nations must have a say in it.

HAMILTONAnd that's why some of those countries are launching efforts in international forums, such as the Convention on Biodiversity, to place limits on geoengineering research. And to say, if we're going to down this route, we want to have a say, because we are the people who are most affected by climate change and will be most affected by geoengineering.

REHMAnd where do you see most of the push for it coming from?

HAMILTONMost of the push for it is coming from scientists in the United States and, odd as it might seem, there's strong support coming, for geoengineering, from certain conservative think tanks in the US, such as the American Enterprise Institute, the Cato Institute. Organizations that, for more than 10 years, have vigorously denied climate science, have led the charge of behalf of fossil fuel corporations, to attack climate scientists. These very same organizations that say climate change doesn't exist are now coming out and backing geoengineering.

HAMILTONThe solution to a problem they previously said doesn't exist.

REHMClive Hamilton. His new book is titled, "Earthmasters: The Dawn of the Age of Climate Engineering." Lots to think about. Thank you so much.

HAMILTONThank you, Diane.

REHMAnd thanks to all of you for listening. I'm Diane Rehm.