Quirks & Quarks

To fight climate change let's launch calcite into space

Leading scientist believes now is the time to take drastic steps to fight global warming.
The latest in solar geoengineering is calcite - it could reflect sunlight while repairing the ozone layer. (NASA)
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Solar geoengineering is a controversial idea that involves intentionally projecting climate altering pollution into the stratosphere, to offset the warming that greenhouse gas pollution is causing. The danger is that the practice could do more harm than good.  

Up until now, sulfate aerosols have been the proposed pollutant. But they could damage the Earth's ozone layer as they reactivate other chemicals already present.

Dr. David Keith, Professor of Public Policy in the Harvard Kennedy School, and founder at Carbon Engineering, a company developing technology to capture of CO2 from ambient air. (Mario Anzuoni/Reuters)

 A major proponent of solar geoengineering is Canadian scientist Dr. David Keith, a Professor of Applied Science, and Public Policy at Harvard University.  

His new study proposes putting calcite — derived from limestone — into the stratosphere. In laboratory models, calcite neutralizes emissions-borne acids in the atmosphere, while at the same time reflecting sunlight and cooling the planet.  

The researchers acknowledge that solar geoengineering is not a solution to climate change, but the risks that come with trying may outweigh the risks that will come with future global warming.       

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