“We’ve crossed the line: Earth is no longer a safe place for humans”

“We have reached what I call a saturation point: the limit of the Earth system’s biophysical ability to remain in its stable state. We are approaching tipping points, on a global scale we are seeing more and more permanent damage to life support systems “. Johan Rockstrom, the influential Swedish scientist who heads the Potsdam Institute for Climate Impact Research (Pik) is sounding the alarm again. And he does it from the pages of the magazine natureson which he has just published, together with the team of researchers led by him, a study entitled “Safe and just Earth system boundaries”.

Basically, the planet has already exceeded the safety limits to host human life in various sectors: the rise in temperatures, the interruption of water systems, the destruction of natural habitats.

Rockstrom and his collaborators have long since identified eight “limits” of the Earth System, which include biodiversity, water, natural ecosystems, land use, the effects of fertilizers and aerosols. Well, from the research published in the latest issue of natures it emerges that human activities have already pushed seven of these eight limits beyond the threshold of safety for our own survival.

The novelty of the approach of the Pik and of the scientists who have come together in a body called the “Earth Commission” is that they no longer only take into consideration the weather events directly attributable to the climate crisis, but all those consequences that could cause damage to the genus human.

“The impacts go beyond heat waves and floods,” Rockstrom explains. “We will have less food security, worsening water quality, rising groundwater, worsening livelihoods, especially among the vast vulnerable majorities around the world.”

A “safe and fair” limit, for example, would have been to keep global warming at 1 degree higher than in the pre-industrial era. But the study confirms that we are already at almost 1.2 degrees. And even if the Paris Accords were followed, stopping the planet’s fever at an increase of 1.5 degrees by the end of the century, it would still be a catastrophe: 200 million people would be exposed to unprecedented average temperatures and half a billion inhabitants of the Earth would have to do with rising seas.

However, the research does not want to be a de profundis. According to the authors “the planetary diagnosis is grim, but we must not lose hope, even if time is running out for a remedy.” Joyeeta Guptaco-chair of the Earth Commission and professor of Environment and Development in the Global South at the University of Amsterdam, confirms: ‘A doctor would say that the Earth is indeed quite sick in many parts: we don’t just have to deal with just the symptoms, but also the causes”.

Having identified a series of parameters (i safe and just boundaries) that help determine the health of the planet can be a very useful tool: “We propose”, concludes the team led by Johan Rockstrom, “that our assessment provides a quantitative foundation for safeguarding the global commons for all people now and in the future”.