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Blocking sunlight at specific areas can stop Arctic melting

Last Updated: Tuesday, October 23, 2012 - 19:37

Washington: Solar geo-engineering can be applied to save the Arctic ice cap if targeted at specific regions of the planet, rather than cooling everywhere equally, a new study has found.

Researchers found that by tailoring geo-engineering efforts by region and by need, a new model promises to maximise the effectiveness of solar radiation management while mitigating its potential side effects and risks.

Solar geo-engineering, the goal of which is to offset the global warming caused by greenhouse gases, involves reflecting sunlight back into space.

By increasing the concentrations of aerosols in the stratosphere or by creating low-altitude marine clouds, the as-yet hypothetical solar geo-engineering projects would scatter incoming solar heat away from Earth`s surface.

"By contrast, our research uses a more systematic approach to understand how geoengineering might be used to limit a specific impact," Gordon McKay Professor of Applied Physics at the Harvard School of Engineering and Applied Sciences (SEAS).

We found that tailored solar geo-engineering might limit Arctic sea ice loss with several times less total solar shading than would be needed in a uniform case," McKay said.

Generally speaking, greenhouse gases tend to suppress precipitation, and an offsetting reduction in the amount of sunlight absorbed by Earth would not restore it.

Both greenhouse gases and aerosols affect the distribution of heat and rain on this planet, but they change the temperature and precipitation in different ways in different places.

The researchers suggest that varying the amount of sunlight deflected away from Earth both regionally and seasonally could combat some of this problem.

"These results indicate that varying geo-engineering efforts by region and over different periods of time could potentially improve the effectiveness of solar geo-engineering and reduce climate impacts in at-risk areas," co-author Ken Caldeira said in a statement.

"While more work needs to be done, we have a strong model that indicates that solar geo-engineering might be used in a far more nuanced manner than the uniform one-size-fits-all implementation that is often assumed," Caldeira said.


First Published: Tuesday, October 23, 2012 - 19:37
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