Earth lies outside its ‘safe operating space for humanity’ in most key measurements, study finds

By | September 13, 2023

Earth is exceeding its “safe operating space for humanity” in six of nine key measures of its health, and two of the remaining three are headed in the wrong direction, a new study says.

The Earth’s climate, biodiversity, soil, fresh water, nutrient pollution and “new” chemicals (man-made compounds such as microplastics and nuclear waste) are all out of control, a group of scientists have said. international scientists in the journal Science Advances on Wednesday. Only ocean acidity, air health and the ozone layer are within limits considered safe, and both ocean and air pollution are trending in the wrong direction, the study says.

“We are in very bad shape,” said study co-author Johan Rockstrom, director of the Potsdam Institute for Climate Impact Research in Germany. “In this analysis we show that the planet is losing resilience and the patient is sick.”

In 2009, Rockstrom and other researchers created nine different large boundary areas and used scientific measurements to judge the health of the Earth as a whole. Wednesday’s paper was a 2015 update and added a sixth factor to the unsafe category. The water moved from the hardly safe category to the no-go category due to worsening river runoff and better measurement and understanding of the problem, Rockstrom said.

These boundaries “determine the fate of the planet,” said Rockstrom, a climate scientist. The nine factors have been “scientifically well established” by numerous external studies, he said.

If Earth could manage these nine factors, it could be relatively safe. But that’s not the case, she said.

In most cases, the team uses other peer-reviewed scientific data to create measurable thresholds for a safety boundary. For example, they use 350 parts per million of carbon dioxide in the air, rather than the 1.5 degrees (2.7 degrees Fahrenheit) warming mandated by the Paris climate agreement since pre-industrial times. This year, carbon in the air peaked at 424 parts per million.

The nine factors are mixed. When the team used computer simulations, they found that worsening one factor, such as climate or biodiversity, also worsened other environmental problems on Earth, while solving one helped the others. Rockstrom said this was like a simulated stress test for the planet.

The simulations showed “that one of the most powerful means humanity has at its disposal to fight climate change” is to clean up its land and save forests, the study said. According to the study, restoring forests to late 20th century levels would provide significant natural sinks to store carbon dioxide instead of air, where it traps heat.

Biodiversity – the amount and different types of life species – is in one of the most concerning conditions and does not receive as much attention as other issues, such as climate change, Rockstrom said.

“Biodiversity is critical to keeping the carbon cycle and the water cycle intact,” Rockstrom said. “The biggest headache we have today is the climate crisis and the biodiversity crisis.”

University of Michigan Environmental Studies Dean Jonathan Overpeck, who was not part of the study, called the study “deeply concerning because of its implications for the planet, and people should be concerned.”

“The analysis is balanced in the sense that it clearly sounds a flashing red alarm, but is not overly alarmist,” Overpeck said. “It is important to emphasize that there is hope.”

The fact that the ozone layer is the only factor for improvement shows that when the world and its leaders decide to recognize a problem and act on it, it can be solved and “for the most part there are things we know how do” to improve the ozone layer. remaining problems, said Neil Donahue, a Carnegie Mellon professor of chemistry and the environment.

Some biodiversity scientists, such as Duke’s Stuart Pimm, have long disputed Rockstrom’s methods and measurements, saying the results aren’t worth much.

But Carnegie Mellon environmental engineering professor Granger Morgan, who was not part of the study, said: “Experts disagree on exactly where the limits are, or how much different systems on the planet can interact, but there we are getting dangerously close. “

“I have often said that if we don’t quickly reduce the way we are stressing the Earth, we will be broke,” Morgan said in an email. “This document says toast is more likely to be burnt.”


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