Sounds like something a comic-book super-villain would do, and Bill Gates certainly has the money to be one. Ben Webster writes in the Times:
The first trials of controversial sunshielding technology are being planned after the United Nations failed to secure agreement on cutting greenhouse gases.
Bill Gates, the Microsoft billionaire, is funding research into machines to suck up ten tonnes of seawater every second and spray it upwards. This would seed vast banks of white clouds to reflect the Sun’s rays away from Earth.
The British and American scientists involved do not intend to wait for international rules on technology that deliberately alters the climate. They believe that the weak outcome of December’s climate summit in Copenhagen means that emissions will continue to rise unchecked and that the world urgently needs an alternative strategy to protect itself from global warming.
Many methods of cooling the planet, collectively known as geoengineering, have been proposed. They include rockets to deploy millions of mirrors in the stratosphere and artificial trees to suck carbon dioxide from the air. Most would be prohibitively expensive and could not be deployed for decades.
Read More: Times