On geo-engineering:

In pursuing the idea, Wingenter is entering a scientific-political minefield— the field of what is called “geo-engineering.”
The most widely discussed geo-engineering proposal, pushed by Lowell Wood of Lawrence Livermore National Laboratory in California, involves a fleet of jets spewing aerosols that would deflect the sun’s rays, cooling the planet in the process.
Other suggestions include launching giant mirrors into space to block some of the sun’s light.
One risk, said Ken Caldeira, an expert in the field at the Carnegie Institution in California, is that geo-engineering might be used as an excuse to avoid cutting greenhouse gas emissions.
“A world with a lot of greenhouse gases and a lot of geo-engineering might be better than a world with a lot greenhouse gases without geo-engineering,” he said.