A gigantic sunshade in the sky While scientists conceded solar geoengineering is 'outlandish and unsettling', they argued it could just work. 'It invokes technologies that are redolent of science fiction – jets lacing the stratosphere with sunlight-blocking particles, and fleets of ships spraying seawater into low-lying clouds to make them whiter and brighter to reflect sunlight,' they wrote in the journal Nature. 'Yet, if such approaches could be realised technically and politically, they could slow, stop or even reverse the rise in global temperatures within one or two years'

Blanket distribution of sunscreen

A gigantic heat-absorbing sponge