Plan B: Geoengineering to Cool the Planet

Sam Kaufmann

Author: Sam Kaufmann is a junior in the College of Arts and Sciences studying Biology.

During a Q & A session at a climate conference last semester, in a room full of 100 people, I asked a simple question: “I’m willing to bet everyone in this room $100 each that the world will not meet the Paris Agreement goals. Would anyone here like to take me up on that?” No one took the bet. Would you?

World Resources Institute’s 2017 brief says that carbon emissions need to peak in 2020 to keep warming to 2°C. With rich economies barely leveling off emissions and developing economies like India growing on the back of fossil fuels, emissions are not going to peak until some time after 2030—when renewables win the price battle with nonrenewables.

It is possible that a sudden gigantic technological or political leap could save us. But such a leap isn’t in sight, so we can’t rely on it.

According to the IPCC, even the existing country-based Paris commitments will lead to at least three degrees of warming by 2100. Every degree of rapid heating feeds climate instability, exponentially increasing extreme weather events like fires, hurricanes, droughts, and heatwaves. Those events will make many major population centers uninhabitable. The world economy will suffer enormously; vast numbers of people will suffer enormously.

We do not have to accept that. There is a Plan B.

The word “geoengineering” calls to mind images of a far-future civilization terraforming newly discovered planets. In fact, “geoengineering” isn’t meaningfully different from “terraforming;” you use advanced technology to change the climate of a planet to something you’d prefer.

In 1815, a volcanic eruption in Indonesia shot a cloud of sulfur particles into the stratosphere. Oxidizing into sulfuric acid, a powerful reflector of light, the cloud significantly reduced the amount of sunlight reaching Earth for about a year. 1816 was known as “the year without a summer”. This uncontrolled climate modification was devastating, if survivable, to human society at the time. But a similar, more beneficial effect could be achieved in a controlled manner by spraying sulfates into the stratosphere from aircraft.

The details of this strategy are surprisingly easy. Specialized cargo planes would be ideal but ordinary 737s would do to start with. Industrial sulfates are cheap, and a few grams of sulfuric acid reflect as much light as a ton of CO2 traps. According to the National Research Council, “solar radiation management” (SRM) can be done for roughly $1 to $10 billion per year.

Why haven’t you heard about this? Because there is a de facto moratorium on research and public discourse. A handful of climatologists and international relations scholars have done preliminary research, but no government or UN body has offered direct support. The UN Convention on Biodiversity condemned geoengineering in its 2012 report.

But once the pain ramps up in rich countries, voters will want something, anything, to make it stop. We need to do the research, have the debates, and air the criticisms now so that we don’t risk a blind, panicked scramble to SRM later.

SRM is a moral hazard. It incentivizes the world to emit more carbon in the hope of fixing the problem later. But that was going to happen anyway. We are already going to emit more carbon than modern civilization as we know it can survive. So, in the short term, does it matter?

Solar radiation management is a Band-Aid. It will not address rising atmospheric CO2 levels; in particular, it does not prevent ocean acidification caused by increased carbon dioxide levels. It will cool the earth, but not in a pattern which is equal and opposite to CO2 warming region by region. Because the sulfates would be most stable near the equator, where their half-life is over a year, SRM will cool the tropics more than the poles and create a world with less temperature variation and therefore less precipitation. It will also have unpredictable regional climate effects, which will put pressure on agriculture and housing, destabilize weather patterns, and harm ecosystems. SRM will hurt people, and its worst effects will fall disproportionately on those who were already most vulnerable and had the least say in its implementation.

But unchecked climate change is guaranteed to do all of those things, except much worse. Although we can’t predict the exact effects of either, we can be confident that one degree of warming plus SRM will do much, much less harm than three degrees of warming.

Human beings—especially environmentalists—have a tendency to desire what is “natural.” We believe that there is a way the planet should or would be without human intervention. According to this view, the way to reduce environmental damage and “save the earth” is simple: pull back our human intervention and let Mother Nature sort herself out the way she wants. But Mother Nature doesn’t want anything; she just is. At this point, human influence on the global climate is so overwhelming that the choice isn’t between the pre-industrial climate and the one we create. It’s between a climate we create unintentionally and one we create intentionally.

Geoengineering will be used to slow and moderate global warming, not to reverse it. We will eventually decarbonize the world economy and implement carbon capture to bring atmospheric CO2 back down. But we won’t do it in the very short term because it’s too expensive and difficult. SRM will keep us afloat until then.

You’ll note that I say “will,” not “would, if SRM is implemented.” This is because SRM or another similar geoengineering technique probably will be implemented. SRM is so cheap that it could be done by any large economy—the US, but also Germany or Saudi Arabia or India. All it takes is one politician with a promise to change the world.

So we must have the conversation. Our choice right now is whether to proactively invest in relevant basic, technical, and policy research now. This preparation wouldn’t be expensive, and it might very well save the world.

Originally published on April 22, 2020.

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