"Scientists have long theorized that injecting reflective particles of some kind into the high atmosphere could reduce the amount of sunlight reaching the Earth’s surface and compensate for the greenhouse effect. High CO2 levels would continue to trap heat, but with less energy coming in to begin with, temperatures on the surface would go down.
Keith’s paper used climate models to cautiously suggest that the method could be adapted to engineer regional effects. The right amount of aerosols in the right place at the right time could restore the Arctic’s frozen glory.
“With an average solar reduction of only 0.5 per cent, it is possible to recover pre-industrial sea ice extent,” the paper says. “Decisions involving (solar radiation management) do not need to be reduced to a single ‘global thermostat.’”
A separate paper concluded that it could all be done with a few modified Gulfstream jets widely available on the used market. Annually, it could cost somewhat less than $8 billion — about the price of a major oil pipeline.
While Keith believes emissions should be cut, he doesn’t advocate such a plan, at least not yet.
He suggested geoengineering may be a viable response to a “climate emergency” — a sudden collapse of ice sheets or a killing drought."