- Country: The United States
- Title: Adjunct Senior Fellow, Council on Foreign Relations
- Education: Harvard University, Massachusetts Institute of Technology
Lucy Berman: Why are so many seemingly respectable people convinced that global warming is not a real problem? Are they are all just cranks or political hacks, or is there really something to debate?
A: It is hard to defend the position that nothing should be done about global warming. The evidence is just too overwhelming. But informed people disagree over the severity of the problem -- in part because nobody really knows how the buildup in greenhouse gases will affect the climate system, and especially because it is hard to assess how nature and humans will respond to a changing climate.
Some people see humans, especially, as highly adaptive; that leads them to worry less about global warming. Others are more pessimistic. What really scares me about climate change are the unknown unknowns -- the possibility that the climate system will respond in radical ways and that nature will adapt poorly. The only way to reduce the odds of those extreme -- some people say "catastrophic" -- outcomes is to control the emissions that cause global warming in the first place. And if those efforts are tardy or fail, then geoengineering is a Plan B that is filled with troubles but better than nothing.
Will Rafey: Can geoengineering ever be a reliable substitute for a transition to renewable, sustainable energy?
A: Per my reply to Lucy Berman, there is no simple substitute for controlling emissions. Renewable energy could be a large part of that effort -- and surely will be -- but it is not the only option. Much higher energy efficiency must play a role; nuclear power can play a major role (if, at the same time, there is attention to controlling the risk of weapons proliferation); advanced coal-fired power plants that safely store most of their pollution underground can also play a role. Geoengineering could be, at best, a Plan B. And if we don't invest to understand it and its flaws, it won't even be Plan B.
Michael Lamb: In the United States, we have made huge strides in improving the environment -- look back to videos of the 1970s -- yet certain people still blame us for the world's problems. Our manufacturing base has decreased, and environmental regulations have increased. Should we not tell the rest of the world that when they catch up to what we have done, we will join them in a worldwide group?
A: The United States -- and most other advanced countries -- has made big progress in solving the pollution problems that the public has cared about. We have made deep cuts in the emissions that cause smog and other local pollution -- though some places still lag, especially the big cities in the south such as Houston, Phoenix, and Los Angeles. We have sharply reduced pollution that causes acid rain. But the story is different for other pollutants, such as CO2 and other gases that cause global warming, which have risen sharply since the 1970s. Partly that is because we haven't cared enough about those pollution problems to spend real resources to solve them, and partly that is because it is hard to solve them -- CO2 is a nearly intrinsic byproduct of fossil-fuel combustion, and fossil fuels are the metabolism of modern economies. Our progress on local and regional pollution such as smog is laudable but not a reason to hold back efforts to control the pollution that causes global warming until other countries catch up. We really need to be in the lead. The United States, for example, emits about five times the CO2 per capita as China.
Mark Miller: United Nations International Panel on Climate Change (IPCC) data -- for the Northern Hemisphere, at least -- demonstrates that temperatures have cycled from a Medieval Warm Period, through a Little Ice Age, and since the turn of the last century, appear to be returning to the temperatures prevalent prior to 1600. CO2 can at most absorb only eight percent of the infrared spectrum, ergo the heat, radiating back from the earth in response to incident solar radiation. Man is responsible for about three percent of the CO2 in the atmosphere. So, at most, man is responsible for 0.24 percent of heat capture from the sun. Water vapor -- clouds -- is responsible for most of the heat capture. Given the interchange of water between the oceans and the atmosphere without any input from man, it is obvious that man's influence on atmospheric temperature is negligible.
So my question is: Since we cannot appreciably affect the major mechanism of global warming -- nor should we wish to -- why should we even consider the diversion of scarce resources to geoengineering the climate content of CO2?
A: The science is a lot more definitive and not as you summarize it. What matters is the perturbation -- the effect of human activities against the background of "normal" fluctuations in climate. The IPCC report that you cite makes that clear and does not support the math you outline. In fact, humans can have a major impact on the climate and are having that impact. First, the "natural" level of CO2 in the atmosphere is about 280 parts per million -- a number that fluctuates, but was the number before the industrial revolution and is a good starting point. Since the industrial revolution, that number has risen about 100 parts per million. Essentially all of that rise (not three percent) is due to humans. Essentially all other greenhouse gases have risen in concentration as well; some have skyrocketed. Most or all of those increases are also traced straight back to humans. Temperature and other aspects of climate vary a lot, but overall temperature has risen, and most of that rise appears to be due to this accumulation of greenhouse gases in the atmosphere. You are right to note that CO2 is a "weak" greenhouse gas, but the volumes are so huge that even though it is weak, the overall effect on climate is huge. Water vapor is, as you note, the most important greenhouse gas, but humans (and nature) do not affect water vapor directly. Rather, the amount of water vapor in the atmosphere is a byproduct of how the climate system operates. Thus, what really matters when thinking about climate change is the original perturbation -- the root cause that leads to changes in the whole climate system. That root cause is mainly the buildup of CO2 and other gases.
Roger Clark: It will take a combination of reducing carbon emissions and a number of different geoengineering approaches -- each appropriate to the conditions found around the world -- to tackle global warming. Unfortunately, only a small number of schemes seem to be highlighted -- most dealing with the mitigation of anthropogenic carbon dioxide or planetary cooling -- while the fact that natural emissions of carbon dioxide and methane are contributing a large percentage of the greenhouse gases is being largely ignored. Concepts like the mining of natural methane and methane hydrates from zones likely to destabilize in river deltas or on continental shelves are rarely discussed. All are possible with current technologies and beneficial to local communities as well as having global impact. Now is the time for as many geoengineering options to be considered and evaluated as possible. Why are only some being discussed and compared as if one winner will be chosen to save the world? Where is the forum for putting alternative ideas into the public arena?
A: There are many geoengineering options. We focused on schemes that would alter the planet's albedo because those seem to be the best understood -- and even those leave many stones unturned -- and they yield rapid changes in climate. Speed matters because we view geoengineering as an emergency option only -- something that societies might do only if climate change turned very ugly. Most of the options in your comment thus aren't really "geoengineering" in our view; they do not involve planet-scale rapid intervention in the climate system. They could make a difference, though I am skeptical at the moment. For example, climate warming might cause methane hydrates to destabilize, which would accelerate climate warming still further. That might be a scenario that leads nations to think about deploying geoengineering systems. But the option you outline -- to mine those hydrates which, I think you imply, would reduce the danger of their destabilizing -- probably won't work. It probably would be extremely expensive, and the mining operation would cause both local and global havoc. Most likely, the mining would destabilize them further because hydrates lose stability if they are exposed to higher temperatures or lower pressures -- all likely if industrial mining operations were attempted. There have been some test projects on hydrate mining with, at best, mixed results.
Ethan Katz: What do you think of the Obama administration's plans to deal with climate change, to the extent that they have announced any?
A: I was somewhat involved as an adviser in the early days of the campaign, and the plan he is outlining reflects those campaign promises. (How wonderful to have a president who honors pledges, at least when the pledges remain relevant.) They are a start, and that is more than the U.S. federal government has done so far. But they are only a start. Much more will be needed to get key developing countries on board. And then, with broader global engagement, much deeper cuts are needed. As the Obama plan unfolds, watch both the efforts to control emissions directly (through so-called cap-and-trade) and also the many efforts (amplified thanks to the stimulus) to invest in alternative technologies that have very low or zero emissions. The group I run at Stanford does a lot of work on this question -- in particular on strategies for engaging the developing countries (http://pesd.stanford.edu).
Steven Stoft: President Obama's carbon cap is expected to put strong downward pressure on emissions. This means business will put strong upward pressures on emissions in the form of bidding up the price of emission permits. Of course, businesses cannot break the cap, but they will keep emission right up at the cap. Doesn't this mean that all other state and national measures to save carbon -- e.g. renewable electricity standards, the Regional Greenhouse Gas Initiative, and California's fuel-efficiency measures -- will fail?
A: At this stage, nobody knows. First, businesses might be able to "break" the cap by purchasing so-called offset credits. Most of the draft bills being considered in Congress allow companies to buy some of these offsets, and most of the serious studies of existing offset markets show that offsets are of dubious quality.
The biggest market is something called the Clean Development Mechanism, a scheme set up under the Kyoto treaty to allow governments to invest in projects in developing countries and earn offset credits. A large fraction of the CDM market, in fact, does not represent real reductions. (See a paper by Michael Wara and me, posted at http://pesd.stanford.edu, for the details. News items on that same site link to detailed investigative reporting on an array of sham CDM projects.)
There are big efforts under way to fix CDM (I am skeptical that the fixes will be easy or effective), and the U.S. Congress is looking at an array of alternative schemes. Second, and fundamental to your question, is the relationship between a federal cap and the various state-based efforts. If the federal cap is less stringent than the state schemes, then both could exist side by side. That's a quite plausible outcome. So far, the RGGI system, which is the scheme that involves most Northeastern states, is likely to be more lax than the federal system. The most recent auctions of carbon credits in RGGI suggest the price is only about $3.50 per ton.
The Obama team, by contrast, envisions that their cap will yield at least $13 to $14 per ton. (Higher prices indicate a tighter cap: when caps are tighter, companies must work harder to comply, and that drives up the price.) That leads to a simple prediction: RGGI will become irrelevant, or it will be forced to tighten. The states that support RGGI are unlikely to abandon their scheme readily, however, because they have learned that they can make a lot of money by auctioning the credits. My guess is that the California system will have a tighter cap (and thus higher prices), although California has not yet set its rules for offsets.
In general, the states that have already created their own caps are reluctant to abandon them even as the federal government develops a federal cap. A plausible outcome is that the United States will have both federal and state systems running in parallel. I pity companies that try to plan compliance in this cacophony of regulatory systems, but that is how much American environmental law unfolds. Eventually, the fragmented state systems will become too onerous and the whole system will be federalized. But "eventually" may be many years down the road.
Louise Aasia: How likely is it that private-sector actors will pursue geoengineering measures on their own, regardless of what governments or international institutions do? What might the consequences be?
A: My coauthors and I are wary about the private sector getting too far out in front on this issue because it will create strong pressure to deploy geoengineering systems. So far, that is not a danger. Indeed, what makes this such a hard issue for public policy is that geoengineering is an option that must be explored (and readied) but, hopefully, never used. Private companies tend not to invest in things that, by design, are unlikely to be used.
That said, there are a few companies looking into parts of what some people think could be geoengineering systems. A couple companies with private capital have looked into schemes that would "fertilize" parts of the oceans, leading to algal blooms that could suck CO2 out of the air. We did not look closely at those options in our research (see my response to Roger Clark, where I note that the albedo schemes that we examined were interesting because they offered possibly large and quick impact on the climate). Among the troubles with the ocean-based systems is that they involve large-scale intervention in the ocean ecosystem, and it would be hard to do that quickly, and nobody really wants to be messing with nature any more than needed.
The private companies that have looked into this option are not doing it because they intend to make money from geoengineering; rather, they sought to get -- eventually -- carbon credits for the CO2 that would be sucked from the air. What they have learned along the way is that people, not surprisingly, are really wary about letting companies mess with the ocean.
One company, Planktos, treated that dissent with considerable arrogance and now is bankrupt. The other company, Climos, is taking a much more measured approach -- evaluating the science carefully, encouraging debate, etc. Whether that will be enough to make a viable, profitable company is unknown. But on the matter of large-scale geoengineering, I doubt there is a viable private-sector model to lead this effort. Government must be in charge, although it might delegate some of the research to private players. It might also create prizes that companies could win if they demonstrate key components of what could become viable geoengineering systems -- akin, a bit, to the X Prizes. If government does this well, then it will be able to steer the research in sensible ways and also ensure that the results are fully public, which is vital to setting the right norms and to ensuring that people worldwide learn what geoengineering could offer and, crucially, learn about the many risks.
Ronal W. Larson: Do you consider biochar to be a geoengineering option, and if so, what is the most serious negative consequence of embarking on its rapid and immediate implementation? Tim Lenton did so categorize biochar in his recent comparison of geoengineering options and seemed to favor it.