Should we fiddle with Earth’s thermostat? This man might know how.
On the wall of David Keith’s airy, book-lined office in Harvard University’s engineering school is a faded 3-by-3-inch card. The framed typewritten label is the badge worn by his father to the United Nations Conference on the Human Environment in Stockholm in 1972. The badge is a signpost in the long march toward global action on the environment and on climate change, which many believe has become the existential crisis of our time. Since then, scientists have mapped out the cumulative risks that a warming planet poses to humans and other species. Nations have come together to set goals for cutting greenhouse gas emissions.
News flash: The world is failing to meet them and failing fast. By almost all accounts, the cuts aren’t happening quickly enough to stop the accumulation of gases in the atmosphere at levels that are already starting to play havoc with our climate, from Sacramento to Sydney.
So Dr. Keith, a Canadian scientist-philosopher, has a radical alternative. It’s not a solution to climate change, more of a last resort, and he’s troubled that we may even need to risk it.
His answer: Turn down the Earth’s thermostat.
Dr. Keith is among the most prominent of a small group of climate scientists working on solar geoengineering. He calls it a “brutally ugly technical fix” that offers near-term salvation in a way that could rewrite the rules of geopolitics just as nuclear weapons did in the 20th century.
He envisions a fleet of high-flying planes releasing sulfur or other chemical compounds in the stratosphere that then form an aerosol mist around the globe. These aerosols would deflect incoming sunlight, dimming the skies below. Think volcanic eruptions that blot out the sun or the meteorite dust kicked up 65 million years ago that may have led to the demise of dinosaurs.
The objective of solar geoengineering would be to slow the warming of the Earth, buying time for humans to finally stop burning fossil fuels and build zero-emission economies. Assuming the idea actually works, it would require an open-ended commitment to maintaining
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