Holdren, a 1981 winner of a MacArthur Foundation "genius" grant, outlined these possible geoengineering options:
• Shooting sulfur particles (like those produced by power plants and volcanoes, for example) into the upper atmosphere, an idea that gained steam when it was proposed by Nobel laureate Paul Crutzen in 2006. It would be "basically mimicking the effect of volcanoes in screening out the incoming sunlight," Holdren said.
• Creating artificial "trees" — giant towers that suck carbon dioxide out of the air and store it.
SHOOT: They should also consider atmosphere processing (as demonstrated in ALIENS] - giant atmosphere processors meant to scrub the air and remove carbon from it while cooling it down.
A cheaper method would involve painting all black surfaces (including roads and rooftops) white.
That's because global warming is happening so rapidly, John Holdren told The Associated Press in his first interview since being confirmed last month.
His concern is that the United States and other nations won't slow global warming fast enough and that several "tipping points" could be fast approaching. Once such milestones are reached, such as complete loss of summer sea ice in the Arctic, it increases chances of "really intolerable consequences," he said.