National Academy: Geoengineering No Substitute for Carbon Cuts

The idea of geoengineering to reverse climate change has been around since the 1960s. The two-volume NAS report says cutting GHGs is the only solution.

Monsoon clouds/Credit: NASA

There's no quick fix for climate change and there won't be for decades to come. The world's only solution is to drastically cut greenhouse gas emissions—and immediately.

That's the takeaway from a new two-volume report out Feb. 10 from the National Research Council, the working arm of the National Academy of Sciences. The report examines whether governments could fight global warming through geoengineering, also known as climate engineering or climate intervention. The strategy involves removing carbon dioxide from the atmosphere or modifying clouds or other Earth systems to reflect incoming sunlight to alter the world's climate artificially.  

"The top line message from the report is pretty clear: there's no climate engineering technology that would be a substitute for large-scale mitigation," said Simon Nicholson, co-director of American University's Forum for Climate Engineering Assessment who did not contribute to the report.

Scientists and policymakers have been contemplating the idea of geoengineering to reverse climate change since the 1960s, Nicholson said. For decades, it was considered a fringe scientific field, with the ideas more reminiscent of those one would read in a science fiction novel than a credible, peer reviewed scientific journal. The 2006 publication of an essay by Nobel Prize-winning chemist Paul Crutzen proposing geoengineering as an "escape route" changed the conversation and threw the field and the accompanying technology out of obscurity and into the mainstream.

Proposed geoengineering technologies vary from fertilizing the ocean with iron to increase it uptake of carbon dioxide to directly capturing the gas from the air as it passes through a machine of some sort. Despite the emergence of the field into popular science in recent years, the National Research Council found that carbon sequestration technology is still decades away from being effective. Attempts to alter clouds or other Earth systems so they reflect more sun and therefore decrease global temperatures, also known as albedo-modification technologies, pose "poorly understood risks," according to the study.

"That scientists are even considering technological interventions should be a wake-up call that we need to do more now to reduce emissions," said Marcia McNutt, editor-in-chief of Science, former director of the U.S. Geological Survey and chair of the National Research Council committee that produced the report. "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."

The National Research Council's findings aren't groundbreaking, Nicholson said. Like the reports from the United Nations' Intergovernmental Panel on Climate Change, it is a summary of the latest research.

Its timing could be a boon to U.S. negotiators heading to Paris later this year to hash out a new global agreement on climate change. For decades, countries have continued business as usual often with the hope that they'd be able to engineer their way out a climate crisis later. The National Research Council's report appears to challenge that thinking.

The report didn't slam the door on these techniques entirely. It recommended that the governments increase their investments in researching and improving the technologies on a larger scale.

"There's absolutely no substitute for slashing fossil fuel emissions in order to prevent catastrophic disruption of the Earth's climate," said Rhea Suh, president of the Natural Resources Defense Council. "But it's prudent to do research into geoengineering because, for instance, improved carbon dioxide-removal techniques could help reduce such dangerous pollution. We also need research because manipulating solar radiation is risky and we must increase our understanding of those risks."

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