Climate change interventions

A National Research Council committee looked at possible aggressive interventions to address global climate change—including Albedo modification techniques, which aim to increase the ability of the Earth or clouds to reflect incoming sunlight—before concluding that strategies to reduce manmade emissions are still the best approach.

“That scientists are even considering technological interventions should be a wake-up call that we need to do more now to reduce emissions, which is the most-effective, least-risky way to combat climate change,” said committee chair Marcia K. McNutt, editor-in-chief of Science and a former US Geological Survey Director.

“But the longer we wait, the more likely it will become that we will need to deploy some forms of carbon dioxide removal to avoid the worst impacts of climate change,” she added as the council, part of the National Academy of Sciences, released its two studies on Feb. 10.

In the second study, “Climate Intervention: Reflecting Sunlight to Cool Earth,” the committee emphasized there is no substitute for dramatic reductions in carbon dioxide and other greenhouse gas emissions to mitigate negative climate change consequences.

“Mitigation, although technologically feasible, has been difficult to achieve for political, economic, and social reasons that may well persist into the future,” it observed. Although many communities where climate change impacts would be felt most are considering ways to adapt, the study said it may be prudent to consider two more aggressive approaches: carbon dioxide removal and Albedo modification techniques.

It immediately identified differences in the two approaches. CDR (which includes carbon capture and sequestration) extends current emissions control strategies, while Albedo modification tries to offset effects of high GHG concentrations but does not address the high concentrations themselves.

Wide range of risks

The committee recommended that research and development investment focus on CO2 removal and disposal on much larger scales. Albedo modification proposals, on the other hand, “introduce environmental, ethical, social, political, economic, and legal risks associated with intended and unintended consequences,” it warned.

Significant cooling may be possible by introducing tens of millions of tons of aerosol gases into the atmosphere, the study conceded. But it said Albedo modification presents several possible risks and repercussions, including uneven impact distribution. The technique also could reduce incentives to reduce and remove emissions. Basically, it would only be a temporary solution.

Uncertainties in modeling both climate change and Albedo modification make it impossible to provide reliable, quantifiable statements about relative risks, consequences, and benefits of such aggressive intervention, the study said. There also is no international forum for climate intervention cooperation and coordination—all making Albedo modification at scales sufficient to alter climate a bad idea at this time.