Humans may have pushed Earth's system beyond 3 of its biophysical thresholds

Washington, September 24 (ANI): In a new international research, scientists have determined that human activities have already pushed the Earth system beyond three of the planet's biophysical thresholds, with consequences that are detrimental or even catastrophic for large parts of the world.

The research was conducted by 29 European, Australian and US scientists.

Scientists have been warning for decades that the explosion of human activity since the industrial revolution is pushing the Earth's resources and natural systems to their limits.

The data confirm that 6 billion people are capable of generating a global geophysical force the equivalent to some of the great forces of nature - just by going about their daily lives.

This force has given rise to a new era - Anthropocene - in which human actions have become the main driver of global environmental change.

"On a finite planet, at some point, we will tip the vital resources we rely upon into irreversible decline if our consumption is not balanced with regenerative and sustainable activity," said co-author Sander van der Leeuw, who directs the School of Human Evolution and Social Change at Arizona State University.

"Until now, the scientific community has not attempted to determine the limits of the Earth system's stability in so many dimensions and make a proposal such as this," explained van der Leeuw.

"We expect the debate on global warming to shift as a result, because it is not only greenhouse gas emissions that threaten our planet's equilibrium. There are many other systems and they all interact, so that crossing one boundary may make others even more destabilized," he added.

In the study, nine boundaries were identified, including climate change, stratospheric ozone, land use change, freshwater use, biological diversity, ocean acidification, nitrogen and phosphorus inputs to the biosphere and oceans, aerosol loading and chemical pollution.

The study suggests that three of these boundaries -climate change, biological diversity and nitrogen input to the biosphere - may already have been transgressed.

Using an interdisciplinary approach, the researchers looked at the data for each of the nine vital processes in the Earth system and identified a critical control variable.

Take biodiversity loss, for example, the control variable is the species extinction rate, which is expressed in extinctions per million species per year.

They then explored how the boundaries interact.

Here, loss of biodiversity impacts carbon storage (climate change), freshwater, nitrogen and phosphorous cycles, and land systems.

According to lead author Professor Johan Rockstrom, director of the Stockholm Resilience Centre at Stockholm University, "Transgressing planetary boundaries may be devastating for humanity, but if we respect them we have a bright future for centuries ahead." (ANI)