'Limestone Sunshade' to Cool the Planet?
The idea of geoengineering a solution to climate change has been discussed for decades, and now a new study proposes a plan that would cool the planet while repairing a hole in the ozone layer at the same time.
The trick: using calcite particles injected high into the stratosphere to reflect sunlight back into space, according to the study by a group from Harvard University published today in the journal Proceedings of the National Academy of Sciences.
While scientists say geoengineering is not a substitute for cutting emissions of heat-trapping greenhouse gases, they say that more research is needed on geoengineering as a possible additional measure to help the planet.
"My view is that solar reengineering is a supplement, and in the end we still have to cut emissions," said David Keith, professor of applied physics and public policy at Harvard and author of the new paper.

NASA