Sprayed Aerosols Could Ease Climate Woes

Sprayed Aerosols Could Ease Climate Woes

Irene Klotz, Discovery News

Dec. 29, 2008 -- It won't solve global warming, but a group of scientists are calling for a focused research program to investigate ways to seed the atmosphere with chemicals that would let the heat out -- literally.

Geoengineering is not a new concept. Governments have changed how and where water flows, filled in lakes and other wetlands for construction, even attempted to control the weather. A project to counter climate change, however, would take geoengineering to an entirely new level.

Leaving aside what may be insurmountable political, cultural and ethical issues, scientists meeting at the American Geophysical Conference in San Francisco earlier this month focused on the practical aspects of releasing gases into the stratosphere that could open Earth's greenhouse.

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"This brings up the question of who would make that decision," said Alan Robock of Rutgers University. And what temperature the world should be.

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Computer Models Show Major Climate Shift As A Result Of Closing Ozone Hole

ScienceDaily (June 13, 2008) — A new study led by Columbia University researchers has found that the closing of the ozone hole, which is projected to occur sometime in the second half of the 21st century, may significantly affect climate change in the Southern Hemisphere, and therefore, the global climate. The study appears in the June 13th issue of Science.

The Earth's ozone layer is located in the lower stratosphere, which lies just above the troposphere (which begins at the planet's surface and reaches up to about 12 km), catching harmful ultraviolet rays from the sun. Until late in the last century, widespread usage of household and commercial aerosols containing chlorofluorocarbons (CFC), unstable compounds which are carried into the stratosphere, lead to significant and rapid ozone depletion. Due to the Montreal Protocol, signed by 191 countries, CFC production worldwide was phased out in 1996.

Observations in the last few years indicate that ozone depletion has largely halted and is expected to fully reverse. As a consequence, the new study finds, the Southern Hemisphere climate change may also reverse. This would be a very tangible outcome of the Montreal Protocol, which has been called the single most successful international agreement to date, and would demonstrate how international treaties are able to make positive changes to the climate system.

"Our results suggest that stratospheric ozone is important for the Southern Hemisphere climate change, and ought to be more carefully considered in the next set of IPCC model integrations," said Seok-Woo Son, lead-author of the study and a postdoctoral research scientist at Columbia's Fu Foundation School of Engineering and Applied Science (SEAS).

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