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  • Dick writes about Earth and planetary science for Science magazine.
 

Abrupt Climate Change Still Looming

3 December 2013 11:00 am
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Abrupt stop. Even gradual climate change could cause abrupt problems in coming decades, including melting ice roads such as this one in Canada and making them impassable, a new report concludes.

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Abrupt stop. Even gradual climate change could cause abrupt problems in coming decades, including melting ice roads such as this one in Canada and making them impassable, a new report concludes.

Climate change poses little threat of causing greenhouse gases to gush from the Arctic or the Gulf Stream to slosh to a stop, at least in this century, concludes a report released today by a committee of the National Research Council (NRC). But the uncertainties associated with passing tipping points in the climate system are dangerously large, the NRC committee finds. To remedy that, the committee recommends the creation of an early warning system to alert policymakers to new threats of abrupt change and, of course, further research to reduce those uncertainties. “The time is here to be serious about the threat of tipping points,” the report concludes, “so as to better anticipate and prepare ourselves for the inevitable surprises.”

NRC foresees some of those surprises coming from some unconventional quarters. In addition to problems created by sudden climate changes over a few decades or even a few years, the committee points to abruptly developing problems created by a steadily changing climate. Rising sea level could suddenly begin to breach sea walls, for example, and thawing permafrost could cause the sudden collapse of buildings, roads, or pipelines.

Some sudden impacts of climate change are already under way, the report notes. Arctic warming has caused a rapid decline in sea ice cover during the past decade that could seriously affect everything from Arctic ecosystems to shipping and oil drilling. And global warming is so rapid—as fast as any warming in the past 65 million years—that species already under pressure from habitat loss and overexploitation are at greater risk of extinction.

To better anticipate the next sudden change, the committee recommends the creation of an early warning system and research to better understand the possibilities. “Right now we don’t know what many of these thresholds are,” said committee Chair James White of the University of Colorado, Boulder, in a statement. “But with better information, we will be able to anticipate some major changes before they occur and help reduce the potential consequences.”

The committee acknowledges that its ambitions for enhanced monitoring, modeling, and synthesis of the knowledge gained would come with a significant price tag. The monitoring alone “in an era of budget cuts is an area of concern,” according to the report. Although an early warning system would eventually become a large program, the committee concedes, it “might better be started through the coordination, integration, and expansion of existing and planned smaller programs.”

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