Global warming is primarily a problem of too much carbon dioxide in the earth's atmosphere, which acts as a blanket, trapping the heat and warming the planet. An international team of researchers has identified that potential 'tipping points' where abrupt regional climate shifts due to global warming could result in natural disasters.
The scientists found evidence of 41 cases of regional abrupt changes in the ocean, sea ice, snow cover, permafrost and terrestrial biosphere. Martin Claussen, director of Max Planck Institute for Meteorology (MPI-M) in Germany and one of the study co-authors, said, "The majority of the detected abrupt shifts are distant from the major population centers of the planet, but their occurrence could have implications over large distances."
In the new study, the researchers analyzed the climate model simulations on which the recent fifth Intergovernmental Panel on Climate Change (IPCC) reports are based. Most of these events occur for global warming levels of less than two degrees, a threshold sometimes presented as a safe limit.
Lead author Sybren Drijfhout, from the Ocean and Earth Science department at the University of Southampton, said, "Our results show that no safe limit exists and that many abrupt shifts already occur for global warming levels much lower than two degrees."
Co-author Victor Brovkin from Max Planck Institute for Meteorology said, "Interestingly, abrupt events could come out as a cascade of different phenomena. For example, a collapse of permafrost in Arctic is followed by a rapid increase in forest area there. This kind of domino effect should have implications not only for natural systems, but also for society."
The study was published in Proceedings of the National Academy of Sciences.