Geo-Engineering to Produce Regional Thermostats for Solar Heat Control

The main aim of solar geo-engineering is to balance the global warming that is being generated by greenhouse gases. This process involves reflecting back the sunlight into the space.

A new study explores the probability of using solar reengineering to counter the loss of Arctic sea ice.  The study suggests that solar geo-engineering can be tailored to reduce inequality or to manage specific risks like the loss of Arctic sea ice. By tailoring geo-engineering efforts by region and by need, a new model promises to maximize the effectiveness of solar radiation management while mitigating its potential side effects and risks.

The solar geo-engineering projects would be able to scatter incoming solar heat away from Earth's surface by either increasing the concentration of the aerosols in the stratosphere or by creating low altitude marine clouds.

But according to the critics of geo-engineering such a global intervention will have an unequal effect around the world and could result in unforeseen consequences. They think that the potential gains may not be worth the risk.

Gordon McKay Professor of Applied Physics at the Harvard School of Engineering and Applied Sciences (SEAS) and Professor of Public Policy at Harvard Kennedy School said, "Instead, we can be thoughtful about various trade-offs to achieve more selective results, such as the trade-off between minimizing global climate changes and minimizing residual changes at the worst-off location."

"There has been a lot of loose talk about region-specific climate modification. By contrast, our research uses a more systematic approach to understand how geo-engineering might be used to limit a specific impact. 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."

The greenhouse gases and aerosols have a great effect on the distribution of heat and rain on this planet, and they alter the temperature and precipitation in different ways in different places.

But the researchers feel that the sunlight that bounces away from Earth both regionally and seasonally could fight 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," says co-author Ken Caldeira, Senior Scientist in the Department of Global Ecology at the Carnegie Institution for Science.

"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. One might say that one need not think of it as a single global thermostat. This gives us hope that if we ever do need to implement engineered solutions to combat global warming, that we would do so with a bit more confidence and a great ability to test it and control it."

The study is being published in the November issue of Nature Climate Change.