We’re now more than halfway through the first installment of Futurography, a project that aims to inform readers about the technologies that will define tomorrow. So far, the geoengineering chapter of Futurography has offered:

• an introduction to the science of tinkering with the atmosphere to mitigate climate change
• a cheat sheet laying out the big ideas and debates
• a reflection on the ethical problems involved with testing the technologies
• a guide to the two questions you should ask yourself about the field

And we have more coming up before we offer a quiz at the end of the month. But whether you’ve read all those pieces or not (though you should!), you probably have questions about geoengineering. What technologies are most promising? What are the biggest dangers? How worried should people be about a rogue billionaire trying to fix climate change on his own?

Two experts came by to answer your burning geoengineering questions!

Jeff Goodell is a contributing editor at Rolling Stone, a fellow at New America, and the author of How to Cool the Planet: Geoengineering and the Audacious Quest to Fix Earth’s Climate. He is joined by Raymond T. Pierrehumbert, who is the Halley professor of physics at the University of Oxford and has called geoengineering “barking mad.”

Jeff Goodell: Hello everyone—happy to be here and happy to take your questions.

Raymond Pierrehumbert: Hello, this is Ray Pierrehumbert, writing to you from Oxford. The frequent mention of active carbon removal in the Paris talks has no doubt stirred up a lot of current interest in geoengineering, and that has spilled over into the other form of climate intervention—albedo modfication and sunshades of various sorts. There's a lot here to talk about, and I'm pleased for the chance to help air the issues, since albedo hacking is an idea that won't go away, no matter how much I might wish for it.

Question: "Hacking the planet" is obviously a loaded concept that makes many people rightly squeamish. But do you think it is getting in the way of adequate research funding and consideration for geoengineering as an option going forward?

Pierrehumbert: I think the main problem is that many people fail to distinguish between the more benign form of geoengineering (carbon dioxide removal) and the more questionable and dangerous form (albedo modification—various schemes to block sunlight, as in artificial volcanoes). Carbon dioxide removal is mostly the form of geoengineering that came up at the Paris climate conference. Carbon dioxide removal needs much more funding than it is getting, and the lack of funding may suffer somewhat from the general fear of doing more messing with the planet than we already are, but I think the bigger problem there is the lack of economic incentives—no reason to invest in it if there isn’t a carbon price. For albedo modification, I think people are rightly scared of it, rightly and viscerally, and some of the nomenclature thrown at it actually is aimed at making it more palatable (like solar radiation “management”). In fact, in the National Research Council report, we called all these things “climate interventions” rather than “engineering” because the state of understanding doesn’t support the implications of precision and predictability and advance testability generally conveyed by “engineering.”

Goodell: Language is important, and the phrase “hacking the planet” is crude, but I don’t think rephrasing or renaming is the main issue here (although people have been trying to do it for years). The main issue is educating people about what kind of research people want to do, and why, and what the real risks are. In addition, research funding is not something that is decided by popular vote, but by scientists and administrators who dole out the money. To the degree that they are influenced by public opinion, language is important. But what really matters is the seriousness of the science and the issues being explored.

Question: Handling climate change inevitably boils down to two (mostly) competing interests: Money and Politics. How do we neutralize the political obstruction and maximize the private-sector monetary incentives that can change the game for the future of our planet?

Pierrehumbert: I disagree with Naomi Klein about a whole lot of things in “This Changes Everything” (see my forthcoming article in the Bulletin of the Atomic Scientists), but on albedo hacking she is right—if it happens, it won’t take into account the needs of the developing world. It will be done as an attempt to preserve a livable climate for investment bankers in rich countries, and will be just another way for the rich world to clobber the developing world.

Goodell: Well, that’s true enough—but then, almost everything comes down to money and politics. I think there is real danger that geoengineering will get taken up by Big Oil and others—in subtle ways, of course—and presented as a way to preserve the climate, or, more likely, “buy us time” to get off fossil fuels. But this kind of corruption infects all kinds of energy and climate debates, and that is why strong voices from scientists and educated politicians is so important.

Question: What carbon sequestration techniques do you think show the most promise?

Goodell: Trees! And as you may know, people like David Keith, a Harvard professor who has been involved in geoengineering as long as anyone, is working on machines that can suck CO₂ out of the atmosphere. The chemistry works, but the costs are high, and the amount of CO₂ removed is very small (unless you covered the Midwest with these machines). Best sequestration strategy of all? Keep fossil fuels in the ground.

Pierrehumbert: Trees by themselves are not so reliable, since they don’t really “sequester” carbon, they just increase the stock in or near the soil and that can easily be released back. Reforestation is good, but what shows more promise is “BECCS,”—burning biomass, but capturing the carbon dioxide produced and putting it in geological formations where it can be sequestered for (hopefully) millennia. Next after that (assuming you want to capture CO₂ already in the air) are a range of technologies that “absorb” (actually adsorb) CO₂ on various kinds of surfaces. Those are expensive right now, but so were photovoltaics 20 years ago. Many people are working on this, not just David Keith, of course, and there are several start-up companies. And all that has been done with just a trickle of investment. It needs much more. Of course the cheapest thing is to catch the CO₂ before it gets into the atmosphere. That can be done with present technology, but without a price on carbon there’s little incentive to do it. It can be done best for natural gas, but also for coal (though at a higher price). The fracking revolution should be accompanied by investment in CO₂ capture from natural-gas burning. But that’s not really in the realm of “geoengineering” the carbon cycle, like air capture is.

Question: If your geoengineering experiment starts to go badly wrong, how do you back it out?

Goodell: That is a very good question, and one that I know Ray has thought a lot about, so I’m sure he’ll have something to say about this. And of course it depends on the kind of geoengineering you’re talking about: with cloud brightening, it’s not a big issue; if you have loaded the sky with sulfate particles and after doing it for 20 years you notice monsoons are shifting, you’re in trouble because if you stop putting particles in the sky, it will be like closing an umbrella, and all the warmth that has been masked by reflecting particles will suddenly be felt. That’s why “slow” and “reversible” are both important qualities of any geoengineering experiment we might someday choose to undertake.

Pierrehumbert: Agreed, this is a very good question. Again, we need to distinguish between CO₂ capture and albedo modification (sunshades). If you were capturing and storing CO₂ and found adverse consequences (e.g., killing ocean bottom life, or creating earthquakes), you could just stop doing it and that would keep the problem from getting worse, but it could take a long time for the earthquakes to die out or marine ecosystems to recover. Since a lot of the effects would be local, these are things you could learn about through small scale trials.

Albedo modification poses much bigger risks in terms of what happens if you find it has to be ended. Technically speaking, if you were increasing reflection by pumping sulfur dioxide into the stratosphere, or by seeding marine surface clouds, you could just stop and the albedo (reflectivity) would return to normal in around a year or less. However, this is actually a threat, not an advantage. The reason is that not only does the albedo change go away, the cooling effect goes away, too, so you are hit with the full effect of pent-up warming in just a few decades. So, if you started albedo modification because of some climate crisis that you couldn’t survive without it, then you don’t really have the option of stopping. It’s like turning off life support, if you get yourself into a situation where you need life support to live. Then, too with regard to turning off albedo modification, there’s the question of what you do if Russia likes a warmer Siberia, but people are dying from heat waves in Delhi, or the monsoon has failed. Can you say “Climate Wars?”

Question: Do we dare to use to technology to manipulate climates to the point that we shift nature’s balance? Could technology be of use in mechanically manipulating parts of weather occurrences to enhance other areas in need? For example, where there is drought can we mechanically manipulate how rain accumulates and shift to another area?

Goodell: This idea of trying to “tailor” regional climate conditions is something that a few scientists think about (as well as old-fashioned rainmakers). Would changing the albedo of clouds off, say, Africa help bring rainfall to the Sahel? It’s possible, but we really understand far too little about the levers and mechanisms of the climate to do that yet.

Pierrehumbert: Responding to the first question here, the thing is that our decisions are already determining what climate and chemical systems our descendants will be stuck with for the next 10,000 or even 100,000 years. That train has left the station, and we can’t escape the responsibility. The question is whether we are going to address the problem by quickly decarbonizing the economy so we don’t make the problem worse, or whether we are going to try to offset the symptoms of the problem caused by CO₂ emission by clobbering the planet harder in another way—hacking the albedo with stratospheric aerosols, e.g. As I’d see it, in that case we’d be just lurching from one crisis to another, responding to one massive problem (CO₂ emissions) by layering on yet another fragile techno-fix that makes our fate even more precarious and makes the climate even harder to understand. That’s not a path to resilience. As somebody said, the basic idea behind albedo modification is “Well, stupidity got us into this problem, so maybe even more stupidity will get us out.” 

As for the second part, geoengineering is a blunt tool. You can’t tailor-make regional climates because the whole climate system is coupled together. If you push one place, it bulges out some other place. One example we know about is that if you try to selectively cool down the Northern Hemisphere, that has drastic consequences in the form of reducing rainfall in the Sahel. We know that you can’t even simultaneously “fix” both the temperature and the rainfall with albedo modification.

Question: How could geoengineering principles or techniques be utilized to terraform a planet like Mars, or thicken the atmosphere to make it breathable, and could advances on that front be used to fuel efforts to control climate here?

Pierrehumbert: I could spend a couple hours talking about this one, as it is a great way of expanding your thinking about basic planetary processes. It would be a bit of a distraction from the main topic of the day, though, and the magnitude of what would need to be done for terraforming wouldn’t really feed back much on what might be needed in the research agenda for keeping our own planet habitable. But just to make a brief comment, the first item of business on Mars wouldn’t be oxygen—it would be to add more surface pressure somehow. If you put more surface pressure on Mars, it would already have enough CO₂ to be pretty comfortably warm (“pressure broadening effect”). The question is where you can get the excess mass needed to bulk up the atmosphere. Once you have it warm enough, green plants will eventually build up enough oxygen. A long-term question on Mars is how to keep enough CO₂ in the atmosphere—it would react with surface rocks and you’d eventually cool off, because Mars is tectonically dead and doesn’t have the trickle of CO₂ outgassing which supports our greenhouse effect over billions of years. You’d have to actively restore CO₂ to the atmosphere. (Good exercise for geochemists: how much energy would that take, to offset the Ebelman-Urey reaction?) (Aw, gee, this was against my better judgement, but you see, I couldn’t keep my hands off this question. And don’t get me started on Venus or Titan!) 

Question: In trying to change the earth's albedo, how could we ensure that we would not cause a drastic temperature drop on the order of a large volcanic eruption (such as Tambora in 1815 or Krakatoa in 1883) that would cause massive problems around the globe?

Goodell: Well, one way to ensure we don’t overdo it would be to start very slowly with albedo modification—in fact, I don’t know any responsible scientist who would want to do it any other way. I don’t think “overdoing it” is the big risk here. The big risk is unintended consequences of even small geoengineering efforts—consequences such as shifting monsoons and unexpected droughts

Pierrehumbert: I agree with Jeff that the most clear and present risk is shifting in rainfall patterns, which are among the hardest things to get right in models, and therefore hard to anticipate or even attribute. However, I also think the risk of overdoing the albedo modification is bigger than proponents think, and requires much better modeling and climate monitoring than we have now or in the near future. I’m not talking about the Snowpiercer scenario, since you would probably notice something wrong before the whole Earth froze over, but there is a vast chain of poorly understood physical processes between the amount of sulfur dioxide you put in the stratosphere and the actual albedo change you get, and it’s easy to overdo it either in terms of a bad geographical distribution of reflection, or through an unanticipated stratospheric weather event that bunches up your aerosols all over one continent, say. These things become most problematic when you are doing a great deal of albedo modification, but that’s exactly the case where, in a panic, geoengineering is likely to be resorted to, in a world where we just keep burning fossil fuels until the crisis becomes intolerable. If you just need “a little bit” of geoengineering, why open that can of worms at all?

Question: Why is everyone so hepped up on using sulfur as a reflective agent? Isn't it a pollutant in and of itself? When it falls back to the earth, won't it make ocean acidification worse? Wouldn't a more neutral (or even base) substance be more useful?

Goodell: Sulfates are basically inert, and yes, although they would fall to earth a year or so after they are injected into the atmosphere, the amount of particles that would rain down would be invisible and have very minor (but not zero) public health consequences. And note, the sulfates we are discussing here are different from sulfur dioxide, which is one of the main pollutants from burning fossil fuels. As for other substances, scientists are thinking about all kinds of things—it’s a question of mass, and of dispersion qualities. I had a recent conversation with a scientist friend who talked about diamonds as a good candidate for particle material. Makes the Beatles song, “Lucy in the Sky with Diamonds,” seem prophetic.

Pierrehumbert: Actually, sulfates are only being discussed for use in the stratosphere. For ocean-surface clouds, it’s sea salt most people are thinking of (the few who think about this stuff at all). There are many, many reasons to not get involved with stratospheric albedo hacking, but the acid rain problem is not high on the list. The reason is that stratospheric sulfate aerosols stay up for a whole year or so, whereas low-level aerosols get washed out in about a week. So, the amount of sulfate you’d be adding to the Earth system in order to hack the albedo in the stratosphere wouldn’t be particularly significant in comparison to what we are already doing in the lower atmosphere by burning dirty coal. There could be local acid snow problems in the polar regions, where most of the stratospheric aerosols get removed, but it’s other aspects of albedo hacking (the “addictive” nature and the termination problem) that really terrify me.

Question: Suppose global warming stabilized at—say—4 degrees higher. What would the costs and parameters of adapting to that be? Assuming we could do it without war, famine and massive worsening of world-wide standards of living, what would that future look like?

Goodell: Not sure if you’re talking about 4 Celsius or 4 Fahrenheit. If 4 C, that is more than double the threshold scientists have sent for dangerous climate change—that’s Four Horsemen of the Apocalypse territory. 4 F is roughly 2 C, which is what the recent Paris Treaty is aiming for. To understand the consequences of that, I’d advise looking at the latest IPPC climate report, which goes into it in plenty of detail.

Pierrehumbert: If we’re talking about 4 C warming, you’re starting to get into some really big and unsubtle effects. Somewhere around there (depending on humidity), it becomes impossible for mammals to lose body heat during tropical heat waves of a sort that start to extend over many tens of days per summer. At that point, mammals can’t survive outdoors. Air conditioning becomes life support, not comfort. At 4C such conditions don’t prevail over the whole summer, but according to Sherwood and Huber by the time you get to 6C there are few days in the tropics when mammals can go outdoors at all. Also, when temperatures exceed 40C, most photosynthesis in land plants (i.e., agriculture) just stops, and 40C days become pretty frequent in the tropics and even some summer midlatitudes (Southeast U.S.) with 4C warming, and things get progressively worse as you go beyond 4C.

Question: Instead of the latest obsession with treating the symptoms of a supposed problem, why isn't there more emphasis on the root cause if there ever was one? Why are the ringleaders hell-bent on putting a butterfly stitch on a gaping wound that's suffering suffering arterial gushing, if there ever was a wound to begin with? Surely it makes more sense to place a global ban on all manufacturing and service industries whose products contribute to the fiction? I'm all for driving a car. But if every rev of the engine is having adverse effects, then I'll curb my usage. I'd rather do that than have experimental sciences taking the lab to the skies with unknown consequences. Surely I'm supposed to grant someone permission to lab-rat-ise me?

Goodell: Good point. That’s why the Paris climate treaty was important.

Question: Can nuclear winter stop global warming?

Goodell: Temporarily, perhaps, but let’s hope it doesn’t come to that.

Pierrehumbert: Since the soot from nuclear winter only stays up for a year or two, you’d need to have at least a limited nuclear war every few years in order to offset global warming, and if you kept pumping out CO₂, you’d have to increase the frequency and scale of your nuclear wars to keep up. Besides that, a lot of that soot comes from burning trees, which don’t grow back because you’ve blocked too much sunlight, and that gives you a CO₂ pulse, too. So, all in all, not a winning idea.

Question: Do we have satellite programs in place now that would be able to detect if a country began intense cloud seeding efforts without international approval?

Pierrehumbert: This is something we thought about quite a lot in the NRC climate intervention reports. Given the difficulties of accurately monitoring cloud changes from space, it would be very hard to directly detect a deliberate attempt to modify low-level clouds (which is one of the two main albedo modification proposals). It would also be difficult to detect small changes in stratospheric aerosols, though somewhat easier than detecting cloud seeding. The main way you’d detect a rogue climate intervention effort of the albedo hacking flavor would be through logistics—the ships entering and leaving port, the stockpiling of raw materials, building a fleet of stratospheric planes, their takeoffs and landings. The logistic footprint would be hard to hide.

Question: How is the geoengineering debate impacted, in terms of climate justice, environment, moral hazard and research, by the following two facts? 1) A recent presentation by Chuck Long at the American Geophysical Union fall meeting argues that aviation emissions has been responsible for a form of ongoing SRM "accidental geoengineering." 2) Current anthropogenic annual sulfur emission are higher than five times the sulfur emitted by Mt. Pinatubo in 1991, and are currently emitted mostly in the Northern Hemisphere, with 98 vs. 6 Tg S year.

Pierrehumbert: This isn’t “geoengineering.” These sort of effects are no different from other inadvertent things we do that affect the climate, including both greenhouse gas emissions, and emissions of sulfate pollution that form reflecting droplets in the atmosphere (aerosols). These are by-products of things we want to do (like fly, burn coal, etc.). Geoengineering, (or better “climate intervention”) is reserved for the case where the climate effect is not an inadvertent by-product, but rather the aim itself. By the way, sulfur dioxide injection is what’s proposed for albedo hacking that is done in the stratosphere, but the amount you’d need to inject over the ocean surface to cause a significant cloud change there makes even the geoengineering boosters blanche. For that reason, the proposals for low-level cloud modification generally involve sea-salt rather than sulfur dioxide. Still a bad idea, but we have to keep the actual scientific facts straight.

Question: Has anybody thought of the the possibility of digging a canal across the United States joining the Pacific Ocean with the Atlantic? The benefits would be enormous I would think.

Goodell: I hope you are joking. That said, when I was researching my book on geoengineering, I learned about a plan of Edward Teller’s—physicist and Godfather of the hydrogen bomb—to dig a new harbor in Alaska with nuclear bombs. Those days, I think, are over. 

Question: Are humans really wise enough to engineer the winners and losers in the coming climate crises? Other wise guys throughout history have failed miserably at making decisions in complex situations that effect the lives and fortunes of millions of people, not to mention countless other species.

Goodell: Are we wise enough to do this? The evidence would suggest we are not. If we were really wise, we wouldn’t have gotten ourselves into a predicament where it was necessary to discuss this at all. But just because we are not wise enough doesn’t mean we won’t do it. Or that we won’t need to do it. For that reason, as well as many others, we need to take this seriously and learn as much as we can about the risks and (potential) benefits.

Question: I've heard during casual conversation that since it's so cheap, a small country could unilaterally decide to do some cloud seeding with sulfates to increase worldwide cloud cover and lower global temperatures. Is this true?

Goodell: Sort of true. Yes, geoengineering is cheap and not technically hard to do (in theory, of course). A nation—or group of nations, or group of individuals for that matter—could in theory do with with a fleet of high-altitude jets outfitted with simple sprayers. This is one reason political scientists and others sometimes compare geoengineering to nuclear weapons—one crazed individual could screw up the planet for everyone. On the other hand, there is a big difference (again in theory) between the capability of carrying out geoengineering and actually doing it right, which would (again in theory) require a careful, well-reasoned scientific approach that would most likely have to be carried out by a country with the resources and the will to do that kind of thing. 

Question: How about a reality check? Americans want to believe that if we each cut back a little—buy a more fuel efficient car, watch our power bills, etc.—that "science" will fix the climate for us. Are we delusional? Are we really such overusers of energy that we all need to make big lifestyle changes (one car per family; one plane trip a year; mostly local food) in order to avoid catastrophe?

Goodell: "Science” won’t fix the climate, but listening to scientists would help. If we want to avoid living on a superheated planet (or a deliberately geoengineered world), the best thing we can do is cut our consumption, buy clean energy, eat less meat. But the most important thing right now is to get involved politically, to demand action from elected officials and vote out climate deniers.

Question: When thinking about a geoengineering project to control climate change, how do you set a target for how much impact you want? Seems like trying to counter-act climate change would be a tricky thing to precisely calibrate.             

Goodell: Good question. It would be tricky to calibrate, in part because there is no steady baseline, and in part because it would be difficult to separate the effect of any geoengineering project from other factors in our (chaotic) climate system. But if we ever did do this, and if we did it right (whatever that exactly means), it would be necessary to improve satellites and other observational tools, as well as to expect that it would take some time to really understand the effects. 

Question: What can we do to stop geoengineering?

Goodell: The best strategy by far would be to quit burning fossil fuels and shift to renewable energy as quickly as possible.

Pierrehumbert: What Jeff said! To clarify what I think needs to be “stopped” is development of albedo hacking technologies. There is no reason whatever to stop development of CO₂ removal technologies, since they put the climate “dial” back in a state approximating where it was. They treat the root cause, not the symptom. But albedo hacking is not so much a precision tool, but an act of desperation. But when backed up against the wall, people do desperate things, no matter how ill advised and even if they wind up making the situation worse. So if we don’t cure our carbon addiction in time, albedo hacking is what you’re going to get, and the result won’t be pretty, and may not even be survivable in the long run.

Question: Tree trunks are very heavy and are made, in large part, from copious quantities of carbon. Lots of carbon was sequestered in the form of trees (and other plant materials) getting trapped underground in a form that pulled their carbon out of the carbon cycle (coal, before humans started burning it). How much of a dent could we put in the over-abundance of atmospheric carbon by simply growing trees, cutting them down, tossing them into old mines and other underground chambers, and burying them?

Pierrehumbert: This is similar to the idea called “BECCS,” where you don’t put the trees (and other biomass) in mines, but rather burn them, capture the CO₂, and put that underground. The reason it doesn’t work to just drop the trees in mines is that you run out of mines and what’s more, bacteria (and their elder cousins archaea) have had billions of years to get good at releasing the energy in organic carbon, which generally is accompanied by releasing greenhouse gases. They’ve had 2 billion years to get good at combining oxygen with organic carbon to make CO₂. BECCS can contribute to the solution, but it’s limited by land area. Many estimates say you couldn’t handle more than 10 percent or so of current CO₂ emissions with biosequestration, and besides it would have really bad biodiversity consequences if you started cutting down the Amazon every few years for biofuel. 

Question: What sorts of career opportunities are there for someone who might be interested in pursuing a career in geoengineering as a way of helping to save the planet? Specifically, I am speaking of someone who comes from a mathematical, scientific, or engineering training that was not specifically designed for this field.

Pierrehumbert: I’d say go for the carbon dioxide removal end of the problem. There are amazing opportunities in doing things with materials science and surface physics. Also, in the geochemistry of how supercritical CO₂ reacts with rocks in geological formation. Also in various ideas for turning CO₂ into a solid mineral form in an energy-efficient way. This is an underfunded area now, but I think the world will wake up soon. Regarding albedo hacking, though it has a few enthusiastic supporters, I think it’s a dead-end fringe area. It’s one of those cases where the gut reaction to it is the right one, and neither end of the political spectrum has much stomach for it. Funding for albedo modification research has more or less dried up in the U.K. and indeed in most of Europe. (Most of the biggish projects were on ethical aspects or other sociopolitical aspects.) I don’t see either Democrats or Republicans putting much into it. Maybe the Koch brothers might fund albedo hacking as a way of getting people to keep burning coal, but do you really want to be part of that?

Question: How viable is technology to recapture heat energy that typically dissipates from buildings for re-use? I understand that the level of heat would generally be quite low, but this seems like a valuable and widespread potential source for supplemental energy.

Pierrehumbert: This is off-topic for geoengineering, but heat recapture is very viable in places that have a district heating grid. It’s done routinely in Stockholm. They capture waste heat from server farms and feed it in to the grid to heat buildings that need it. They’re even going to start capturing waste heat (much of it body heat) from the Central Railway station. But to make it practical, you need a district heating infrastructure. 

Question: If CO2 levels do reach 500 and higher, an almost certain scenario, and corresponding temperatures is projected to increase by 4C or higher from pre-industrial levels, how effective will geoengineering be in its current form in preventing temperature rise and corresponding sea level rise from reaching an unacceptable level?

Pierrehumbert: Sticking to albedo modification (rather than carbon dioxide removal), the problem with albedo modification is that it doesn’t really eliminate the problem—it just masks it, distorts the climate in other ways, and puts the climate in a precarious state where you have a potential for even greater catastrophe from warming. You could probably cool the Earth on the average by 4C by pumping aerosols into the stratosphere, but the aerosols need to be renewed continually, whereas CO₂ is forever. If you ever were forced to stop the aerosol injection (global war, unacceptable side effects, disagreement over what the climate should be like, terrorists or nations who don’t like your geoengineering targeting your facilities) you get hit with the 4C warming in just a few decades, which is surely even worse than having it set in over two centuries, which is already bad enough. So although you might get some temporary relief (apart from the people who don’t like the rainfall changes) you actually put the world in a more precarious state. What other thing have we as humanity ever sustained as a global action for thousands of years? What makes us think we can do this when we haven’t been able to agree on doing something as reasonable and (relatively) easy as kicking the fossil fuel habit?

Question: I just wanted to say I loved The Principles of Planetary Climate. I like to quote it when arguing with stupid people on the Internet. Do you have any plans for upcoming books?

Pierrehumbert: Thanks! I loved writing it. I’m working on a second edition, which will include a lot of new stuff on cumulative carbon, but also a ton of exoplanet stuff that was too new to make it into the first edition. I’ll pre-release some of that material online in the form of iPython notebooks. The other book I’m working on right now is a math methods book showing how Python can be used for problem-solving both in pure and applied math and in physics. I also have an idea to translate Yngve Ryd’s book Eld from Swedish into English, but haven’t heard from the copyright holders yet or lined up a publisher. Eld is a bit like the book Norwegian Wood, but even better, and more concentrated on what the Sami people know about wood and fire. News you can use!

That's all for today, folks. Thanks so much for joining us, and special thanks to Jeff and Ray for taking part in today's chat!

This article is part of the geoengineering installment of Futurography, a series in which Future Tense introduces readers to the technologies that will define tomorrow. Each month from January through May 2016, we’ll choose a new technology and break it down. Future Tense is a collaboration among Arizona State University, New America, and Slate. To get the latest from Futurography in your inbox, sign up for the weekly Future Tense newsletter.