Climate in Context: August 25, 2010

Published: August 25th, 2010 in Impacts, Responses, Climate, Extremes, Oceans & Coasts, Sea Level, Geoengineering, Climate in Context

New Study Says Geoengineering Schemes Will Struggle to Reduce Sea-Level Rise

Graphic showing different geoengineering concepts. Credit: Lawrence Livermore National Laboratory.

As we’ve detailed, geoengineering is increasingly being viewed by some scientists, ethicists, and policymakers as an option to seriously consider in order to prevent the most severe consequences of climate change. Various proposals have been put forward, including injecting sulfur dioxide (SO2) into the stratosphere to reflect incoming solar radiation, or launching large space mirrors that would also redirect incoming heat from the sun. Such measures could theoretically cut down on the temperature increase that would otherwise occur due to human emissions of greenhouse gases, such as carbon dioxide.

But could they be effective in preventing sea level rise, one of the most far-reaching and worrisome consequences of climate change?

Not unless you are willing to go all in on geoengineering – while also significantly reducing greenhouse gas emissions – says a new study published by an international team of researchers. The study, published in Proceedings of the National Academy of Sciences, analyzes the effects that five different geoengineering approaches would have on sea level rise, and finds that all but the most aggressive geoengineering proposals would still allow sea level to increase substantially during this century. A key reason for this is that while geoengineering may be able to rapidly cool global temperatures, sea level responds much more slowly and is expected to react to the warming of recent decades for many years to come.

“… we find that sea-level rise by 2100 will be 30 centimeters higher than 2000 levels despite all but the most aggressive geoengineering under all except the most stringent greenhouse gas emissions scenarios,” the authors write.

In an article in Nature News, Alan Robock, a geophysicist from Rutgers University in New Jersey who was not involved in the new study, was quoted as saying that reducing greenhouse gas emissions will give more bang for the buck as far as sea level rise is concerned. "Reducing emissions of greenhouse gases will have a much larger impact," he said.

Lead author John Moore of Beijing Normal University in China said in the same article: "Anything that isn't reducing the amount of carbon dioxide in the atmosphere is like putting [on] a bandage rather than actually solving the problem.”

Shameless Plug: Climate Central CEO Heidi Cullen on "The Colbert Report" Tonight!

Check out Comedy Central’s “The Colbert Report” tonight at 11:30 Eastern, as our CEO and Director of Communications Heidi Cullen shows off her improvisational skills as tonight’s guest. She will discuss climate change as well as her new book “The Weather of the Future.”

A Skeptical Take on Russian Heat Wave/Climate Change Link

Veteran environmental journalist Tom Yulsman posted snippets from an interview with Martin Hoerling, who runs a unique research group at the National Oceanic and Atmospheric Administration (NOAA) that aims to sort out the causes of extreme weather events. Needless to say, Hoerling has been rather busy this summer, with the historic heat wave in Russia and the deadly flooding in Pakistan making international headlines. In the interview, Hoerling expresses doubts that climate change is connected to the Russian heat event, based on an analysis of “atmospheric blocking” patterns and other data.

“In other words, the 2010 situation isn’t following on the heels of a progression of more and more of these things happening ether over Russia, or frankly over any other place that we can see over the Northern Hemisphere. So it stands out as a . . . black swan. It comes out of the blue in terms of its severity. It does not follow on the heels of a progressive increased frequency,” Hoerling said.

However, other scientists have come to different conclusions, such as Stu Ostro at The Weather Channel, and Peter Stott of the UK Met Office. Climate Central Senior Research Scientist Claudia Tebaldi weighed in on the difficult task of attributing causes of extreme events last week.

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