Does the Paris Agreement Open the Door to Geoengineering?

If we’re serious keeping warming “well below 2°C, geoengineering may be necessary.

The Paris establishes an aspiration goal of holding climate change to 1.5°C, with a firmer goal of holding the global temperature decrease “well below” 2°C. As a practical matter, the 1.5°C goal almost certainly would require geoengineering, such as injecting aerosols into the stratosphere or solar mirrors. Even getting well below 2°C is likely to require steps of that kind or a technological breakthrough for another kind of geoengineering, removing CO2 from the atmosphere. None of this has to happen soon, but sometime between now and the end of the century, something along these lines would probably be required.

It’s always good to begin with the actual text of the agreement. Here’s the language of the agreement about the goal in Article 2(1)(a): “Holding the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change.” Admittedly, this language is stated as an aim of the agreement rather than a mandate, but it’s worth thinking about what would be necessary to accomplish this aim. And it’s possible that it’s really just intended as symbolic, like the 1972 Clean Water Act’s long-forgotten goal of eliminating all water pollution by 1985.  Nevertheless, the Paris Agreement does place these temperature goals on the table, and we should give them careful consideration.

I don’t quarrel with the idea that it would be desirable to attain these goals if we can. It is true that a number of scientists now think that the 1.5° target is needed to avoid the risk of dangerous climate change. So if there’s a realistical way to reach this target, or at least something under 2°, we should certainly give that serious consideration.

The question, however, is whether it is feasible to reach that goal through emission cuts. On that score, as Ann explained in an earlier post, there is considerable doubt. On an optimistic view, the goal is achievable — but only with immediate, rigorous emissions reductions combined with new technologies to remove CO2 from the atmosphere. Ann points out that extraordinary efforts would be required for a country like the U.S., like increasing our current use of renewables thirtyfold. This is consistent with what I’ve read on the subject. For instance, a recent summary of the literature concludes,

IPCC results suggest that limiting temperature increase to <1.5°C by 2100 would require concentration of less than 430 ppm CO2-eq), an enormous challenge. . . . While the literature on the feasibility of reaching this target remains scarce, aggressive mitigation strategies would be fundamental, without any further delay. This entails not only swift global cooperation and exemplary institutional agreements but also massive investments in decarbonizing the global economy with zero net emissions before the end of the century as well as substantial and early negative emissions, particularly carbon dioxide removal strategies . . . . While some argue that a 1.5°C scenario is still feasible, others judge it as no longer within reach.

I would not bet the house, let alone the planet, on “swift global cooperation,” “exemplary institutional arrangements,” and “massive investments” happening quickly. This suggests that, much as we need to cut emissions, emissions are probably not going to get us to 1.5°. Indeed, I have doubts about whether the political will exists to make the huge effort required even to achieve the 2° goal purely through emission cuts.  Any realistic trajectory involves, at the least, new technologies to remove massive amounts of carbon from the atmosphere (which one scientist has called a “technological utopia”).  Short of enormous scientific breakthroughs one that front, solar radiation management to reduce the light reaching the surface seems necessary instead.

For these reasons, it appears to me, geoengineering begins to look necessary as a practical matter if we are going to hit such ambitious goals. Although it involves risks, the risks are less severe if we make a strong an effort as possible to cut emissions first, so that geoengineering doesn’t need to carry so much of the weight of emissions reductions.

I’m not particularly a fan of geoengineering, and I will be happy to be wrong about this. Maybe new energy technologies will be able to get us the kinds of cuts we need quickly and cheaply enough to attain the goals. Otherwise, though, if we are serious about those temperature targets, we may end up with little other choice than layering some geoengineering efforts on top of aggressive emission cuts.









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Reader Comments

3 Replies to “Does the Paris Agreement Open the Door to Geoengineering?”

  1. Just how engineering the dimming of the sun which powers photosynthesis, the most potent part of CO2 ecology, will improve things is a dubious issue. The only way such solar dimming engineering can be presented is if one leaves photosynthesis out of the equations. That is an engineers prescription for chaos.

    On the other hand there are safe, simple, sustainable, immediately deployable, and best of all very inexpensive methods of enhancing photosynthesis on this blue planet. The new Paris Accord very specifically endorses, even demands, the enhancement of natural photosynthesis by restoring plant life in trees and in seas.

    My work, the largest trial of ocean pasture restoration covering nearly 50,000 sq. km in 2012 in the N Pacific, showed that the potency and immediacy of restoring nature simply works! While some say the proof is in the pudding I can do one better as from my restored ocean pasture the largest catch of salmon in Alaska history was produced. Where 50 million Pink Salmon were expected to be caught the following year in Alaska, that would be a fantastic catch, instead 226 million Pink salmon were caught. Today scores of millions of meals of that healthy salmon are being served to needy American kids in the USDA food aid programs courtesy of the incredible surplus of salmon that thrived and survived on their revived ocean pasture and were caught. Ask any of those kids whether they believe repurposing hundreds of millions of tonnes of CO2 into the fish they are surviving on was a good idea.

    While the tens of thousands of delegates in Paris are to be praised for their efforts, and raising the goal of spending trillions of dollars over coming yeas to control and repurpose CO2 is perhaps a good thing. Better is simply doing the lions share of the work right now at a cost of a mere millions of dollars per year. At a cost of those few millions of dollars per year many billions of tonnes of our menacing CO2 will be repurposed into ocean life itself. In the bargain billions of additional fish will swim into our nets and onto the plates of people in need helping to end world hunger.

  2. Japan, S Korea Plan 61 New Coal Plants in Next 10 years, Despite Global Climate Deal:

    “….Less than a week since signing the global climate deal in Paris, Japan and South Korea are pressing ahead with plans to open scores of new coal-fired power plants, casting doubt on the strength of their commitment to cutting CO2 emissions….”

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About Dan

Dan Farber has written and taught on environmental and constitutional law as well as about contracts, jurisprudence and legislation. Currently at Berkeley Law, he has al…

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About Dan

Dan Farber has written and taught on environmental and constitutional law as well as about contracts, jurisprudence and legislation. Currently at Berkeley Law, he has al…

READ more