With greenhouse gas emissions unabated, scientists are increasingly concerned that different components of the Earth system will be stressed to their “tipping points,” defined as critical thresholds at which small perturbations can qualitatively alter the state or development of a system. The collapse of the Antarctic ice sheet, leading to dramatic sea level rise, is one example of a tipping point in the Earth system.
At the recent General Assembly of the European Geosciences Union (EGU), a group of European climate scientists introduced a new 4-year project that will urgently advance current understanding and identify tipping point thresholds that scientists say, if crossed, would be very dangerous for life on Earth.
Funded by the European Union’s Horizon 2020 program, Tipping Points in the Earth System (TiPES) already enlists more than 30 European scientists from more than 15 institutions.
“The most important thing is that this will have impact,” says Peter Ditlevsen, a University of Copenhagen climate scientist and the TiPES project lead and main coordinator. “This is the whole discussion of 1.5° warming or 2.0°—of what is safe. The short answer to that right now is we don’t know.”
Ditlevsen points out that Earth system tipping points are definitively found in the paleorecord, but modeling and theory do not adequately explain the abrupt changes.
“The current modeling is getting better but still does not explain processes that are strongly nonlinear,” he says.
According to Ditlevsen, key goals for TiPES are interdisciplinary collaboration to clarify theory and refining modeling to explain the dynamics and thresholds of climate change tipping points.
Identifying Tipping Point Components
Niklas Boers, a scientist at Germany’s Potsdam Institute for Climate Impact Research and TiPES associate coordinator, presented an outline of the TiPES project at an EGU session on 11 April.
Boers identified the six real-time tipping point concerns for which TiPES will provide critical threshold and system dynamics data: the Atlantic Meridional Overturning Circulation; the Arctic and Antarctic ice sheets and sea ice; the Amazon rain forest ecosystem; the South American and Asian monsoons; the Mediterranean region, with its risk of desertification; and the alpine regions, which are already experiencing dramatic melting glaciers.
“I would be really happy if after 4 years we would be able to give more precise estimates of the critical values of the anthropogenic forcing, in terms of greenhouse gases released to the atmosphere, at which we would expect any of these major tipping points to tip,” Boers says.
TiPES is currently seeking to expand, and project leads anticipate having a full team in place in early September. An official launching ceremony for TiPES is set for mid-October at the Institut Henri Poincaré in Paris.
Anna von der Heydt, a climate scientist at the Institute for Marine and Atmospheric Research in Utrecht, Netherlands, and another TiPES associate coordinator, says she is excited that TiPES will both clarify key scientific questions, such as her current focus on the equilibrium climate sensitivity, and also enlist a cross-disciplinary approach to tackle tipping points.
“We bring together so many different disciplines,” von der Heydt says. “We have the mathematicians, we have the climate scientists, we even have people dealing with societal decision-making, so we really have a good group of people to do these tipping point challenges.”
—Richard Blaustein (@richblaustein), Science Writer