The realities of climate change are front-page news every day. Temperature records are being smashed. Wildfires are raging. There is no sign of things going back to “normal”. If anything, they will only get worse.
Last year, when the planet was convulsing with the arrival of a pandemic, we pinned our hopes on technology – in the form of an mRNA vaccine – getting us out of our crisis. The vaccine was a technological intervention, injected into the arms of billions of people. Could we (should we?) look to technological solutions to our climate crisis, too?
This is the question posed by Holly Jean Buck in her 2019 book After Geoengineering: Climate Tragedy, Repair, and Restoration. Zooming with me from Buffalo, New York, where she’s a professor of environment at the University of Buffalo, Buck is blunt in her assessment. The pace of climate change, and the insufficiency of humanity’s current response, have effectively already made the choice for us: mankind will have to engage in some kind of “geoengineering” – an umbrella term for various methods of intentional, planetary-scale climate intervention – whether we like it or not.
Geoengineering refers to any number of ways that humans can change our climate through interventions. The two main types of geoengineering are carbon engineering, which aims to suck carbon out of the atmosphere, and solar engineering, which aims to reflect solar energy away from Earth.
“We’re in a climate crisis,” she tells me. “Mitigation isn’t going fast enough. Adaptation needs far more support than it’s getting. It’s clear that we need to remove some amount of carbon from the atmosphere.”
How much? “Hundreds of billions of gigatons,” Buck says. “We have emitted so much, and now we have so much legacy carbon. The challenge isn’t just cutting emissions.” The second challenge is “removing the carbon that’s up there. It’s this massive cleanup operation that we need to undertake this century.”
The idea of deliberately altering the climate can be frightening and distasteful, including to many environmentalists. But Buck argues that climate engineering is coming whether we like it or not. “If people on the environmental left – people who care about climate change – just reject all of these approaches out of hand, then we lose the ability to shape them, which would be a grave mistake,” she says.
The simplest form of geoengineering is the kind of carbon removal many of us learned about in school: planting trees. “Land-based solutions are really important, especially in the next decade or so, because they can be implemented quickly – and we know how to plant forests,” Buck says. She points to other kinds of land-based climate interventions that show promise. Changing agricultural practices can be used to store more carbon in the dirt. Other strategies include storing carbon in wetlands, ocean iron fertilization, or different approaches involving rock weathering.
But land-based solutions, though a helpful beginning, probably won’t be enough, Buck says. To plant enough trees to soak up enough carbon to sufficiently cool our planet, we would have to fundamentally change the way we use land in ways that would make our economy and many of our lives unrecognizable. And there are other risks to relying too heavily on land-based techniques.
“A lot of land-based approaches are vulnerable to climate change itself,” Buck explains. “You don’t want a wildfire to wipe out these removals that you’ve been banking on, right?” Massive reforestation efforts could go up in smoke.
But land-based solutions are not the only option. Carbon removal can also be accomplished with industrial technologies. Buck points to a carbon mitigation strategy called geological carbon capture, which is already widely used to reduce the emissions of heavily polluting industries. “You could outfit, well, scrubbers basically, on a factory, and these collect carbon dioxide. Then you inject [the carbon] underground, into a cavern, and keep it there, under the rock, for a very long time. You keep monitoring it, to make sure it stays where you want it to be.”
There are risks to injecting large amounts of carbon into rock; Buck laments the under-regulated “wild west atmosphere” of fracking, which caused earthquakes in some parts of the US. But scientists have learned from that experience, and technologies exist to keep underground carbon in place. And new techniques may make geological carbon capture safer. “There’s a lot of new research about how to get carbon dioxide to turn into rock quicker once you inject it” underground, Buck says.
This is a carbon mitigation technique that has proved efficient in reducing emissions at an industrial scale, and it has been in use for decades, meaning that the safety and science of the technique are well understood. Buck’s hope is that this technology could advance and be used not just for mitigating carbon emissions, but for removing carbon.
“It becomes carbon removal” – as opposed to mitigation – “if you’re removing the carbon just from the ambient air,” Buck says. There are now machines that can “scrub” carbon out of the air; the carbon can then be transported and stored underground. Without these machines, the technique can also be used to create bioenergy, which involves “producing biomass” – say, a very carbon-dense type of plant – “and combusting it at a power plant, and separating out the carbon and storing it underground again”.
This strategy – using a spectrum of carbon-engineering techniques to inject carbon deep beneath rock – is the most effective and safest, Buck believes. But unless humanity gets its act together soon, we may forced to entertain much riskier climate mitigation strategies. “If we don’t remove carbon, and decarbonize, and reform how we use land, and rework our transportation systems, and change industrial systems fast enough,” Buck says, “then there’s the possibility that people will pitch the idea of solar geoengineering.”
Solar geoengineering is a kind of climate mitigation – thus far theoretical – that involves “blocking a fraction of incoming sunlight and sending it back out into space, which has a cooling effect”. Most solar-engineering techniques involve using special planes to inject gas into the stratosphere. The gas particles would reflect sunlight away, changing both the quantity and the quality of sunlight that reaches earth.
This kind of geoengineering would certainly cool the planet, at least for a while. But it would not solve the fundamental problem of too much carbon in the atmosphere. “It doesn’t get to the root,” says Buck. “It doesn’t remove emissions. It’s just a blanket of intentional pollution that cools things down.”
And solar geoengineering might create other problems, Buck says. What would a different kind of sunlight do to humankind, or to other living creatures? What would it do to agriculture, and our food supply? We don’t know. Would there be food shortages? Would the sky still be blue? We don’t have those answers, and solar geoengineering remains a risky proposition until we do.
How optimistic is Buck that humanity will attain a livable future without having to resort to solar geoengineering? More than I expected. The vision that she articulates is ambitious. It would require international cooperation and vast overhauls of infrastructure. It would also mean that the United States and other capitalist countries would have to reorient themselves to a more centrally planned economy, devoted less to maximizing growth than to minimizing carbon. It would mean overcoming vast political differences and competing incentives the world over in order to unite in global common cause.
But Buck thinks that the incentives for cooperation in the existential climate intervention project are great enough to ensure at least some success.
“I do think that if people share a common goal, they might disagree about how to reach that goal, but maybe just having the common goal is enough,” she says.
The greatest clean-up operation of history – the clean-up of carbon in our atmosphere – may well happen within our lifetimes. And, if Buck is right, there is no better time to start it than right now.