Abrupt Climate Transitions: New Research Reveals Hidden Climate Risks

Fresh data on Climate Modeling suggest that regional climate transitions in response to greenhouse gas concentrations are notoriously difficult to predict. Researchers from the University of Bordeaux reveal evidence of 37 forced regional abrupt changes in various climate systems, eight of which occur at a global warming level of less than 2 degrees, a threshold often considered a safe limit. The study highlights the potential for a gradual trend of destabilization of the climate system with respect to such shifts, as global mean temperature changes increase.

Key Takeaways:

• The research identified 37 forced regional abrupt changes in the ocean, sea ice, snow cover, permafrost, and terrestrial biosphere after a certain global temperature increase.
• Eighteen out of 37 events occurred for global warming levels of less than 2 degrees, a threshold often presented as a safe limit.
• The study found no compelling evidence for a general relation between the overall number of abrupt shifts and the level of global warming.
• Abrupt changes in ocean circulation occur more often for moderate warming (less than 2 degrees), whereas over land they occur more often for warming larger than 2 degrees.
• The number of abrupt shifts identified in Representative Concentration Pathway (RCP) 8.5 scenarios was significantly larger than in other scenarios of lower radiative forcing.
• The study suggests the potential for a gradual trend of destabilization of the climate system with respect to such shifts, as global mean temperature changes increase.

Statistics:

• 37 forced regional abrupt changes in the ocean, sea ice, snow cover, permafrost, and terrestrial biosphere were identified in the study.
• Eighteen out of 37 events occurred for global warming levels of less than 2 degrees.
• 18 out of 37 abrupt changes occurred in ocean circulation for moderate warming (less than 2 degrees).
• 19 out of 27 abrupt changes occurred in over land for warming larger than 2 degrees.

Sources:

• "Catalogue of abrupt shifts in Intergovernmental Panel on Climate Change climate models." Proceedings of the National Academy of Sciences of the United States of America, 2015;112(43):E5777-E5786.
• National Academy of Sciences, www.nasonline.org/
• Proceedings of the National Academy of Sciences of the United States of America, www.nasonline.org/publications/pnas/
• University of Bordeaux, Environm & Paleoenvironm Ocean & Continentaux, F-33615 Pessac, France.