In a climate crisis, is geoengineering worth the risks?

More research on such tech as ocean seeding and space mirrors is needed, some scientists say

Mumbai aerial

Hoping to supplement the water supply to Mumbai, India, in 2010, city managers conducted four cloud seeding experiments over nearby water bodies. Aircraft spread dry ice or tiny silver iodide particles into the upper parts of clouds to induce rain. The results were inconclusive.

Dinodia Photos/Alamy

Geoengineering ideas — tinkering with the climate to delay or halt the worst effects of global warming — have been around for decades.