Geoengineering

The Very Optimistic New Argument for Dimming the Sky

The year is 2055, and climate change has fully set in. Months-long heat waves regularly kill infants and the elderly, and food shortages are testing governments on every continent. While the world is finally reducing its carbon emissions, the cuts aren’t happening fast enough, and scientists say Earth will keep rapidly warming for at least another century.

To stave off a crisis, China and the United States jointly propose an audacious scheme: They will inject sulfate aerosols into the high atmosphere to dim the sun’s rays, as happens naturally after a huge volcanic eruption. The two countries say the plan will restore order and lower the planet’s fever. But critics assert that the aerosols will distort the planet’s climate even further, weakening the monsoon and setting off droughts across Asia and Africa.

The scenario may sound like science fiction, but the debate over the prudence of this technique—called solar geo-engineering—has already begun.

On Monday, a new paper from a team of researchers claimed that it is possible to dim the sky in such a way that no region of the planet will be made significantly worse.