Human activities have breached safe levels for six of these boundaries and are pushing the world outside a “safe operating space” for humanity, according to the report, published on Wednesday in the journal Science Advances.
The nine boundaries, first set out in a 2009 paper, aim to establish a set of defined “limits” on changes humans are making to the planet – from pumping out planet-heating pollution to clearing forests for farming. Beyond these limits, the theory goes, the risk of destabilizing conditions on Earth increases dramatically.
The limits are designed to be conservative, to enable society to solve the problems before reaching a “very high risk zone,” said Katherine Richardson, a professor in biological oceanography at the University of Copenhagen and a co-author on the report.
She pointed to the unprecedented summer of extreme weather the world has just experienced at 1.2 degrees Celsius of global warming. “We didn’t think it was going to be like this at 1 degree [Celsius]” she said. “No human has experienced the conditions that we’re experiencing right now,” she added. »
» Science.org » Earth beyond six of nine planetary boundaries