Solar Geoengineering Methods Should Be Targeted
October 22, 2012

How To Block The Sun’s Rays And Reduce Emissions

Michael Harper for — Your Universe Online

Sometimes, the best solution to a problem is the easiest one. The real difficulty lies in the application of said solution. Take, for instance, the issue of global warming and greenhouse gasses. The simplest solution to these matters is to somehow block some of the sun´s harmful rays from the Earth, bringing the temperature down and, ideally, stop the melting of the polar ice caps and other effects of global warming. The difficulty therein is understanding how to block these rays and, more importantly, which areas of the world need this sort of treatment. It´s an issue which hasn´t gone unnoticed by scientists and researchers who have taken the idea of solar geoengineering, or the science of reflecting the sun´s rays away from Earth, quite seriously. Now, some of these scientists have issued a study which, not surprisingly, suggests that when it comes to solar geoengineering, what works in Antarctica might not work in the tropics.

Researchers and co-authors David Keith and Ken Caldeira will now have these results published in the November issue of Nature Climate Change.

“Our research goes a step beyond the one-size-fits-all approach to explore how careful tailoring of solar geoengineering can reduce possible inequalities and risks,” said Keith, a Professor of Applied Physics at the Harvard School of Engineering and Applied Sciences (SEAS) and Professor of Public Policy at Harvard Kennedy School.

“Instead, we can be thoughtful about various tradeoffs to achieve more selective results, such as the trade-off between minimizing global climate changes and minimizing residual changes at the worst-off location.”

Together, Keith and Caldeira are hoping that such a tailored approach can reverse the effects of global warming, specifically the loss of ice in the arctic.

“There has been a lot of loose talk about region-specific climate modification,” continued Keith.

“By contrast, our research uses a more systematic approach to understand how geoengineering might be used to limit a specific impact. We found that tailored solar geoengineering might limit Arctic sea ice loss with several times less total solar shading than would be needed in a uniform case.”

Greenhouse gasses often work to reduce the amount of rain falling on the Earth´s surface. Simply blocking these gasses and reducing the amount of sunlight to reach land would not be enough to alleviate this problem. While greenhouse gasses and aerosols can affect the amount of rainfall and heat on the planet, they do so in different ways in different areas. While simply blocking these gasses and reducing the amount of sunlight might do the trick in one area, it will almost certainly have quite a different effect in other parts of the world, according to Keith and Caldeira´s research.

“These results indicate that varying geoengineering efforts by region and over different periods of time could potentially improve the effectiveness of solar geoengineering and reduce climate impacts in at-risk areas,” explained Caldeira, a Senior Scientist in the Department of Global Ecology at the Carnegie Institution for Science.

These 2 scientists say that while they´re using a very sophisticated, state-of-the-art model to make these assumptions, there are far too many variables in the Earth´s climate to make any hard and fast judgments. Nonetheless, Keith and Caldeira say their models suggest a nuanced and tailored approach to solar engineering is key when it comes to reducing the amount of harmful rays and gasses in the Earth´s atmosphere.

Recently, other scientists have suggested a sort of “sunblock” technology which would effectively reduce the amount of sun to reach the Earth´s surface. While this approach seems much different from Keith and Caldeira´s proposal, the sunblock scientists have also said this sort of approach would only be necessary in extreme situations.