Space mirrors to combat global warming? Scientists mull 'geoengineering' schemes

摘要

If desperation breeds unconventional ideas, then the world is desperate about global warming. Motivated by concern that government policies to combat climate change may be too little, too late, some scientists are suggesting a solution that is the global equivalent of slathering on sunscreen at the beach. Blasting millions of tiny mirrors into space, seeding clouds over the oceans and injecting sulfur into the upper atmosphere may not be the ideas that spring immediately to mind when hoping to cool the planet. But these are the things, often referred to as geoengineering, that are increasingly being considered by some serious climate scientists who hope to buy time for current policies aimed at reducing greenhouse gas emissions to take hold. Widely accepted calculations say that if 2% of the sun's rays were blocked from hitting the earth, it could stop global warming. But not everyone sees the effects of geoengineering as benign.