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Will geoengineering buy us time to cut carbon emissions or just prolong the pain?
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Will geoengineering buy us time to cut carbon emissions or just prolong the pain?

Some observers say high-tech climate fixes are a moral imperative. Others say they are a moral hazard.
March 21, 2024

Let the best of Anthropocene come to you.

One way to address our planet’s carbon dioxide problem is to stop burning fossil fuels. Hopefully we’ll get there one day but the reality today is that we haven’t even reached peak emissions. In fact, we’re still climbing the carbon curve. Another tack is to focus on specific outcomes we want to avoid, such as rising temperatures, and address those directly. A couple of million tons of sulfur aerosols sprayed into the upper atmosphere each year, for example, might reflect enough sunlight to offset all the global warming from climate change. It’s a tempting proposition that is orders of magnitude cheaper than weaning society off coal, oil and gas. There’s also direct air capture of carbon dioxide, which goes to the root of the problem, albeit at a much higher price. 

But some people warn that dimming the sun or sucking down CO2 will let us off the hook for the tough tasks of decarbonization, potentially setting us back decades. 

Here we ask—is there really a moral hazard when it comes to climate action?


• • •

We’re Not Playing a Zero Sum Game

1.  The 2% solution. As a species, we’re already pumping around 100 million tons of sulfur into the atmosphere each year, mostly from fossil fuel power plants, causing nastiness from acid rain to global warming. But a tiny 2% fraction of that amount, released into the stratosphere, could instead lower temperatures, slow sea level rise, and reduce extreme weather events. David Keith, founding director of the Climate Systems Engineering Initiative at UChicago, is a proponent of at least discussing solar radiation management. “Even if you did a 10th of a percent, you would have some impact in reducing climate change a little bit later in the century,” he said in an engaging podcast last year. “The economic benefits are huge, and they come most to the world’s poorest. [In one study], it did more to cut the income inequality between countries than almost anything else you can imagine.”

Projected economic impacts of solar geoengineering
Harding, AR. 2020. Climate econometric models indicate solar geoengineering would reduce inter-country income inequality. Nature Communications.

2.  It’s a science problem, not a moral one. Keith goes on to point out: “There are lots of examples of these moral hazards in public policy and they don’t mean we shouldn’t do things. There were people who argued strongly that we should not put airbags in cars because they would encourage more dangerous driving.” Author Oliver Morton dives into the collective psychology of geoengineering in this essential essay, and concludes: “To imagine that humans can simply stop being a planet-changing force is unrealistic. Thinking that we might find a way to act responsibly may be just as daft. But it seems to me a better foolishness.” 

3.  Humans are smart enough to work in parallel. In an effort to test whether geoengineering might actually derail traditional decarbonization, Gernot Wagner and Christine Merk of the Kiel Institute for the World Economy conducted an experimental public information campaign reaching about 340,000 people on Facebook. They tested whether posts about geoengineering made people more or less likely to engage with content about cutting emissions—and found no effect in all but the most inflammatory posts. “If we dial up things to 1,000, we can indeed get moral hazard, or its inverse. But sensible descriptions of (solar) geoengineering invoke neither,” says Wagner.


  • • •

It’s Better to Just Rip Off the Band-Aid

1. Geoengineering sets up a false carbon economy. Full decarbonization will be expensive, about $3.5 trillion annually in the US through 2050, according to the National Public Utilities Council. But if that hard work is done, we’d have an economy with zero-carbon power generation, resilient renewable energy, smog-less cities, and sustainable industries for generations to come. While some geoengineering projects appear to be cheaper today, enough direct air capture to get to net zero emissions could actually cost around the same, calculates the World Economic Forum. And assuming we keep burning carbon, these megaprojects will have to grow year-on-year just to tread water. 

2.  Playing into the hands of Big Oil. The nonprofit Center for International Environmental Law made an impassioned argument against geoengineering in 2019, stating that “the hypothetical promise of future geoengineering is already being used by major fossil fuel producers to justify the continued production and use of oil, gas, and coal for decades to come.” It fears new technologies will derail efforts to cut emissions and render carbon taxes obsolete, and undermine the political will for the true systemic change we need.

3.  Massive projects, massive risks? Rob Bellamy, a lecturer in climate and society at the University of Manchester, gave a very readable interview to Undark magazine last month where he recited a laundry list of potential problems with solar geoengineering. These include disruption to weather patterns around the world (including crucial monsoons in Asia), knock-on effects to agricultural production and ecosystems, the possibility of increased acid rain and ozone depletion. “There should be a moratorium or a ban on immediate deployment, because we just don’t know enough about the effects yet to be able to do it at a global scale,” he says. Some researchers think that missing one season of complex atmospheric modification could lead to horrific termination shocks.

Possible ancillary impacts of solar geoengineering
source: Felgenhauer, T., et al. 2022. Solar Radiation Modification: A Risk-Risk Analysis, Carnegie Climate Governance Initiative (C2G).


• • •

What To Keep An Eye On

1.  Drowning states. You might imagine nations threatened by sea level rise would be the biggest champions of quick-fix geoengineering. But at a recent UN meeting Pakistan and Fiji were vehemently opposed to solar radiation management, saying that they saw many more risks than benefits, according to this wonky but eye-opening report at Legal Planet. With the US also shying away from geoengineering, that leaves the EU as the bloc currently most open to revisiting the UN’s 2010 de facto moratorium on large-scale efforts.

2.  More down to earth technologies. How does the moral argument shift when geoengineering looks different, or comes with positive rather than negative side effects? Enhanced rock weathering and ocean alkalinity enhancement both capture carbon with added benefits—more fertile soil and less ecosystem-wrecking acidification, respectively. Neither is as cheap as spraying sulfur but could find more scientific and political acceptance in the years ahead.

3.  Science in turmoil. Harvard University just canceled a long-planned and somewhat controversial small solar geoengineering experiment, highlighting the difficulty of getting such projects off the ground. Its advisory committee “stressed the need to engage with the public early on, to listen to their concerns, and to develop a plan to respond to them,” reports MIT Technology Review.

4.  A growing start-up ecosystem. Don’t expect much to come of nano-scale climate stunts like Make Sunsets’ sulfur-and-helium balloon releases, but there are more serious geoengineering-curious non-governmental organizations out there, such as non-profit SilverLining and its Safe Climate Research Initiative.

Top image: Based on Banksy’s Umbrella Girl

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