Can We Geoengineer the Climate?

• Under a White Sky: The Nature of the Future
• By Elizabeth Kolbert
• Crown (2021)

“Geoengineering” is increasingly discussed as a way to neutralize or even roll back the effects of climate change. It proposes various gigantic projects to cool the Earth, or absorb carbon dioxide, or otherwise mitigate the climate disaster we’ve got ourselves into.

It’s an intriguing idea, and when you think about it we’ve been geoengineering the planet ever since we started setting bushfires hundreds of thousands of years ago — and especially since we began clearing land for agriculture.

What’s more, we’ve been very successful engineers. Early in this short, beautifully written and appalling book, Elizabeth Kolbert cites a 2018 scientific report that states: “the mass of humans is an order of magnitude higher than that of all wild mammals combined.... In fact, humans and livestock outweigh all vertebrates combined, with the exception of fish.” In other words, we’ve engineered the planet to suit ourselves. Why not just build on our previous success?

Kolbert describes some of our recent and current efforts. They are impressive in both their scale and in the sophisticated science they involve. But she also shows us how likely they are to create still larger problems.

The brilliant design of the boomerang

We understand that our metastatic spread across the planet, enhanced by ever-improving technology, is causing a climate crisis as well as environmental catastrophes and mass extinctions. Many of us assume that if technology got us into this mess, it can get us out of it. Kolbert gives us several examples of such techno-fixes, each of them as brilliant and dangerous as a boomerang.

The first of these is the attempt to clean up the Chicago River. It once ran thick with garbage and human shit that then poured right into Lake Michigan, the city’s only source of drinking water. It was also, of course, the source of recurrent typhoid and cholera outbreaks. To clean up, Chicago rebuilt its north-flowing river into a south-flowing canal that emptied into the Mississippi.

“But reversing the Chicago didn’t just flush waters toward St. Louis,” Kolbert says. “It also upended the hydrology of roughly two-thirds of the United States.”

Chicago’s chemical waste drained into an enormous watershed; among other problems, it nourished an explosion of water weeds like Asian milfoil. Rather than try to poison the weeds, the authorities of the 1960s adopted a solution proposed by Rachel Carson, author of Silent Spring: fight biological threats with biological controls.

So they imported Asian carp, both to control weeds and to clean up sewage-treatment ponds. The carp soon escaped into the Mississippi and began moving north, crowding out native species of fish and driving freshwater mussels close to extinction. They now threaten the ecosystems of the whole Mississippi basin, from the Gulf of Mexico to Manitoba and Ontario, and from the Appalachians to the foothills of the Rockies.

The electrified canal

To keep the carp out of the Great Lakes, the U.S. Army Corps of Engineers now electrifies the Chicago Canal, while people make a living catching the fish to turn them into fertilizer, pet treats and corn dogs; as Kolbert observes, people are good at overfishing and this is one time when it’s a good idea. But she also points out that we are now trying to control our control of nature.

Trying to restore nature is equally challenging. Kolbert describes the intense efforts taken to preserve a single species, Cyprinodon diabolis. It’s an inch-long fish that lives only in a pool, 60-feet long and eight-feet wide, in a Nevada cave called Devils Hole.

“The Devils Hole pupfish,” Kolbert tells us, “may well be the rarest fish in the world.” Guarded behind a ten-foot fence topped with barbed wire, Devils Hole sees few visitors except scientists who conduct pupfish counts four times a year by diving into the pool in scuba gear. The pupfish live in the top 75 feet of the pool, which at one end is 500-feet deep and fed by an enormous aquifer. When Kolbert came along, the team she was with counted 195 fish: “This was sixty more pupfish than had been counted in the previous census, and higher than anyone had dared guess. High-fives were offered all around.”

Kolbert later did the math: all those pupfish collectively weighed about a hundred grams. “This is slightly less than the weight of a McDonalds Filet-O-Fish sandwich.”

Devils Hole was threatened in the 1960s and ‘70s by developers who pumped so much water out of the aquifer that they threatened to lower the pool’s level below where the pupfish lived. That effort was defeated, but scientists took the point. To ensure the safety of this one species, they even created a kind of imitation Devils Hole to try to breed still more pupfish, with an ecosystem just like the original. But a beetle from the cave flourished too well in its new home, and began devouring pupfish larvae. Now the scientists build beetle traps.

Force-marching evolution

Kolbert finds still more dedicated scientists working to preserve Australia’s Great Barrier Reef, which is rapidly dying in a sea growing warmer and more acidic thanks to our emissions. Healthy reefs provide resources for enormously diverse habitats; sick ones turn to rubble and slime. Here and there, some corals seem to survive warm water or acidity or both, and marine biologists try to force-march evolution by interbreeding these varieties under artificial conditions, putting them back in the sea, and hoping they’ll flourish.

But the scientists think that at best they’re buying the Great Barrier Reef a few decades of life while we somehow manage to halt emissions and begin to cool the planet.

Probably the most ambitious geoengineering idea of them all is to scatter sulphur compounds (or other reflective materials) in the upper atmosphere to reflect sunlight and heat back into space. After all, major volcanic eruptions like Pinatubo in 1991 and Tambora in 1815 did just that. Tambora especially created worldwide chilling, including snow in Quebec City in June 1816.

The drawbacks, though, are nasty: sulphur dioxide from Pinatubo lowered global temperatures by one degree, but consumed a third of the ozone layer in the tropics. Sulphur dioxide also triggers acid rain. Calcium carbonate would avoid such problems, but might create even worse ones.

Kolbert tells us it would be relatively cheap to design and build a fleet of giant aircraft that could scatter reflective particles, but we would eventually find ourselves living under a white sky, not a blue one.

‘You think you’re doing the right thing’

Advocates for such geoengineering projects say we don’t even have a choice; we’ll do it or suffer catastrophic temperature increases. But Kolbert quotes a professor who rejects the idea altogether: “It’s the unintended consequences.... You think you’re doing the right thing. From what you know of the natural world, it should work. But then you do it and it completely backfires and something else happens.”

Most of the other examples in the book describe just such backfires: Asian carp eating much more than Asian milfoil, cane toads that poison animals that eat them, beetles intended to copy the pupfish ecosystem that eat pupfish instead. Kolbert doesn’t hit us over the head with the moral because we can see it very well for ourselves.

Nor does she point out that these are all merely mitigation efforts: like the coral scientists in Australia, their purpose is to buy time. In that time we have to go cold turkey off our fossil-fuel addiction, develop other energy sources, and learn to live on much less energy.

We’re going through a kind of dress rehearsal for that right now. Everyone understands that we need to lock down and stay that way until COVID-19 runs out of new targets. But we can’t quite bring ourselves to do that, so we loosen restrictions, crowd together and give the virus yet more chances to spread and mutate and spread again.

Perhaps we can learn from the pandemic how to live within our means if we want to live at all. Perhaps.