Shield the earth?

Some of you might remember the movie «Highlander» where the earth is protected by an artificial shield against cosmic rays, since the ozone layer had completely disappeared. Guess what ... some IvyLeaguers actually suggested such a solution as a counter-measure to global warming:

The effect would be to uniformly reduce sunlight by about 2 percent over the entire planet, enough to balance the heating of a doubling of atmospheric carbon dioxide in Earth's atmosphere.

Once again «we» try to treat symptoms instead of ripping out the root of the problem. Carbon dioxide absorption will still acidify the oceans with unpredictable catastrophic ramifications.

The total mass of all the fliers making up the space sunshade structure would be 20 million tons. At $10,000 a pound, conventional chemical rocket launch is prohibitively expensive. Angel proposes using a cheaper way developed by Sandia National Laboratories for electromagnetic space launchers, which could bring cost down to as little as $20 a pound.

Of course that's all for the good of mankind, isn't it? Financial ulterior motives and other firms than NASA and ESA pushing into space is just a little bon-bon.