In 2009, a team of researchers, led by Jonah Rockstrom from the Stockholm Resilience Centre, identified nine distinct areas of human-driven change to the Earth’s biosphere: climate change, ocean acidification, stratospheric ozone depletion, alteration of nitrogen and phosphorus cycling, freshwater consumption, land use change, biodiversity loss, and aerosol and chemical pollution.
By exceeding each of the boundaries, we enter into a “zone of uncertainty” – planetary conditions that are entirely unfamiliar to us.
“The boundary is not like the edge of the cliff,” said Ray Pierrehumert, an expert on Earth Systems at the University of Chicago, told The Washington Post. “They’re a little bit more like danger warnings, like high-temperature gauges on your car.”
Scientists aren’t certain whether crossing these boundaries will bring on a catastrophe, but since the past 11,000 years – called the Holocene – have been characterized by a remarkably stable climate, presumed to have made human civilization possible in the first place, driving the aforementioned nine “planetary boundaries” beyond certain limits are likely to make the Earth a much less hospitable place.
Rockstrom and his colleagues wanted to see how likely we are to bring an end to Holocene and enter Anthropocene, a controversial geological term denoting an era where human activities have a significant impact on the Earth’s ecosystems.
The resulting 2009 paper, while highly influential, failed to take into account the fact that some of the “boundaries” are not in fact global in scale.
The new report, led by Will Steffen of the Australian National University and published Thursday in the journal Science, updated past methodology and even included a new “boundary”, called “novel entities”, which designates new compounds that the Earth has not seen before.
Results showed that much of the planet is currently in the “yellow zone of uncertainty with increased risk” with regards to four out of the nine “boundaries” – biodiversity loss (species extinction), land use change (deforestation), climate change (atmospheric CO2 concentrations) and ocean acidification (flow of anthropogenic phosphorous and nitrogen into the oceans).
Researchers hope that his information, scheduled to be discussed next week at the World Economic Forum in Davos, Switzerland, will help delegates of different nations set up effective and sensible emission policies.
Study authors say that curbing the negative impact of human activities is of utmost importance if we want to ensure a decent livelihood for future generations.
“It might be possible for human civilization to live outside Holocene conditions, but it’s never been tried before,” claimed study co-author Steve Carpenter, director of the University of Wisconsin-Madison Centre for Limnology. “We know civilization can make it in Holocene conditions, so it seems wise to try to maintain them.”