Climate 'Tipping Points' May Arrive Without Warning, Says Top Forecast

A new University of California, Davis, study by a top ecological forecaster says it is harder than experts thought to predict when sudden shifts in Earth’s natural systems will occur — a worrisome finding for scientists trying to identify the tipping points that could push climate change into an irreparable global disaster.

“Many scientists are looking for the warning signs that herald sudden changes in natural systems, in hopes of forestalling those changes, or improving our preparations for them,” said UC Davis theoretical ecologist Alan Hastings. “Our new study found, unfortunately, that regime shifts with potentially large consequences can happen without warning — systems can ‘tip’ precipitously.

“This means that some effects of global climate change on ecosystems can be seen only once the effects are dramatic. By that point returning the system to a desirable state will be difficult, if not impossible.”

…As U.S. presidential science adviser John Holdren (not an author of the new UC Davis study) recently told a congressional committee: “Climate scientists worry about ‘tipping points’ … thresholds beyond which a small additional increase in average temperature or some associated climate variable results in major changes to the affected system.”

Among the tipping points Holdren listed were: the complete disappearance of Arctic sea ice in summer, leading to drastic changes in ocean circulation and climate patterns across the whole Northern Hemisphere; acceleration of ice loss from the Greenland and Antarctic ice sheets, driving rates of sea-level increase to 6 feet or more per century; and ocean acidification from carbon dioxide absorption, causing massive disruption in ocean food webs.

Physorg