An international team of Southampton scientists have identified potential ‘tipping points’, where abrupt regional climate shifts could occur due to global warming.
In the new study, published in Proceedings of the National Academy of Sciences of the United States of America (PNAS), the scientists found evidence of 41 cases of regional abrupt changes in the ocean, sea ice, snow cover, permafrost and terrestrial biosphere.
Many of these events occur for global warming levels of less than two degrees, a threshold sometimes presented as a safe limit.
Lead author, Professor Sybren Drijfhout from the department of Ocean and Earth Science said:
“This illustrates the high uncertainty in predicting tipping points. More precisely, our results show that the different state-of-the-art models agree that abrupt changes are likely, but that predicting when and where they will occur remains very difficult.”
Examples of detected climate tipping include abrupt shifts in sea ice and ocean circulation patterns, as well as abrupt shifts in vegetation and marine productivity. Sea ice abrupt changes were particularly common in the climate simulations.
Martin Claussen, director of the Max Planck Institute for Meteorology (MPI-M) and one of the co-authors, added:
“The majority of the detected abrupt shifts are distant from the major population centres of the planet, but their occurrence could have implications over large distances.
“Our work is only a starting point. Now we need to look deeper into mechanisms of tipping points and design an approach to diagnose them during the next round of climate model simulations for IPCC.”