Monday, January 13, 2014

How Close Are We to the Tipping Points from Climate Change?

Abrupt Impacts of Climate Change:Anticipating Surprises (201 page pdf, James W.C. White, Richard B. Alley, David E. Archer, Anthony D. Barnosky, Jonathan Foley, Rong Fu, Marika M. Holland, M. Susan Lozier, Johanna Schmitt, Laurence C. Smith, George Sugihara, David W. J. Thompson, Andrew J. Weaver, Steven C. Wofsy, National Academy of Sciences, Dec. 3, 2013)

Also discussed here: An Update on Risks of Abrupt Jolts from Global Warming (Andrew C. Revkin, New York Times, Dot Earth, Dec. 3, 2013) And here: Investigation of the Magnitudes and Probabilities of Abrupt Climate TransitionS (IMPACTS) Project (Lawrence Berkeley National Laboratory)

Today we review an assessment of climate change in terms of how far it has advanced and what the risk is of crossing a tipping point, in terms of climate impacts for the rest of the century. The authors give a low risk of major changes in ocean current circulation and overturning, the melting of major ice sheets such as the polar ice caps as low, while giving a moderate risk to such impacts as extreme heat waves and floods and rapid state changes in ecosystems which puts vulnerable populations of people in danger as well as endangered species of wildlife. They recommend improved scientific monitoring and a better understanding of the climate system as part of an abrupt change early warning system. arctic sea ice extent  

Key Quotes:

“This study differs from previous treatments of abrupt changes by discussing both the abrupt changes in the physical climate system (hereafter called “abrupt climate change”), as well as the abrupt changes in the physical, biological, or human systems that result from steadily changing aspects of the climate system (hereafter referred to as “abrupt climate impacts”).”

 “Right now, we don’t know what many of these thresholds are…But with better information, we will be able to anticipate some major changes before they occur and help reduce the potential consequences”

“Climate is not the only stressor on the Earth system—other factors, including resource depletion and ever-growing human consumption and population, are exerting enormous pressure on nature’s and society’s resilience to sudden changes.”

“Carbon dioxide emissions from the energy sector will rise 20 percent by 2035 ..according to the IEA’s 2013 World Energy Outlook… this leaves the world in a trajectory consistent with a long term increase of 3.6 C, far above the internationally agreed 2 C target ”

“Summertime heat waves will likely become longer, more frequent, more severe, and more relentless with decreased potential to cool down at night. Increases in heat-related deaths due to climate change are likely to outweigh decreases in deaths from cold snaps…In general, heat waves and the associated health issues disproportionately affect more vulnerable populations such as the elderly, children, those with existing cardiovascular and respiratory diseases, and those who are economically disadvantaged or socially isolated”

“No matter how clear our foresight, no matter how accurate our computer models, a belief about the future should never be mistaken for the truth. The future, as such, never occurs. It becomes the present. And no matter how well we prepare ourselves, when the imagined future becomes the very real present, it never fails to surprise.”—Alan AtKisson, Believing Cassandra
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