If I remember well, the Russians aired an idea a couple of years ago to launch a solar umbrella into outer space, position it between the sun and the earth, and manage the flow of photons to earth by increasing or decreasing the umbrella's opaqueness.

Climate engineering, you say?

Science Adviser Lays Out Climate and Energy Plans

John Holdren, President Obama's science adviser, began speaking to the media on Wednesday for the first time. The Associated Press emphasized some statements he made in support of testing ways to counteract global warming through what has become known as " geo-engineering" -- emergency interventions to cool the atmosphere should less drastic measures fail. Dr. Holdren said that the Associated Press article implied incorrectly that this strategy for climate management was under serious consideration at the White House. This is not the case, he said in an email distributed to a variety of scientists and other contacts last night:

    I said that the approaches that have been surfaced so far seem problematic in terms of both efficacy and side effects, but we have to look at the possibilities and understand them because if we get desperate enough it will be considered. I also made clear that this was my personal view, not Administration policy. Asked whether I had mentioned geo-engineering in any White House discussions, though, I said that I had. This is NOT the same thing as saying the White House is giving serious consideration to geo-engineering - which it isn't -- and I am disappointed that the headline and the text of the article suggest otherwise.

Dr. Holdren's support for research on geo-engineering aligns him with Ralph Cicerone, the president of the National Academy of Sciences, who told The Times in 2006, "We should treat these ideas like any other research and get into the mind-set of taking them seriously." Their notion is to have a "Plan C" if emissions trajectories are not bent downward and the higher end of warming projections comes to pass. (Join the geo-engineering googlegroup to track daily discussions on this question.)

But this is a charged issue for many environmentalists and some scientists (including Jane Lubchenco, the new under secretary of commerce for oceans and atmosphere) who oppose such interventions with nature because they could produce unintended harms, falsely imply that we can engineer our way out of any problem or blunt efforts to cut emissions of greenhouse gases at the source.

Can you say "EMERGENCY"?

"It is not necessary to have hope in order to persevere."