PARIS - First disbelief, then panic. The alarmist predictions of a team of international scientists published in "Nature" in June are starting to make waves online: "The end of the world is for 2100," say many blogs, websites and forums. Entitled "Approaching a state-shift in Earth's biosphere," it is true that the study, co-signed by more than 20 scientists belonging to a dozen international institutions, isn't very optimistic.

It points to the imminence of an irreversible collapse of Earth's ecosystems. To support their analysis, the authors analyzed work that describes the biological disruptions of the seven great planetary crises: the Cambrian explosion, 540 million years ago; the five massive extinctions – some of which annihilated 90% of life on Earth - and the transition from the last ice age to our era, 12,000 years ago.

"All of these transitions coincided with constraints that modified the atmosphere, the ocean and the climate on a global scale," say the authors. The same phenomenon is currently taking place: according to the scientists, almost half of the climates present on Earth today could soon disappear, replaced by never before seen conditions for living organisms on 12% to 39% of the planet's surface.

Above all, this radical transition could take place with an unprecedented brutality. "The last planetary disruption provoked extreme biological changes in only 1000 years," says Arne Moers, a biodiversity professor at Simon Fraser University in Vancouver who cosigned the study. "On a geological scale, that is like going from early childhood to adulthood in less than a year. And yet what is happening today is going even faster."

Even worse: inertia could soon spin the system out of control. "Our planet has no memory of its former state," say the authors. "We are taking an enormous risk modifying the Earth's radiative state: brutally tipping the climatic system into a new equilibrium to which the ecosystems and our societies will be unable to adapt."

Destructive trends

The massive greenhouse gasses that we emit aren't the only ones responsible. Pressure exerted by the human species ranges from the "fragmentation of natural habitats" to "demographic growth" via "excessive consumption of resources." Already, 43% of the Earth's ecosystems are used to fulfill the needs of 7 billion inhabitants. The threshold that can saturate humanity's ability to endure and adapt, or even throw it off course, is near.

"An additional 7% and we will have reached a point of no return," say the scientists. The work of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (Ipbes), the "GIEC of biodiversity" which should meet for the first time in 2013, won't contradict them. They've already noted that a species goes extinct ever 20 minutes, and that the rhythm is accelerating. Over the past 200 years, since the beginning of the industrial era, depending on the species, this rhythm has been 10 to 100 times the natural rhythm of extinction observed by scientists over a 500 million year period. It could soon be 10,000 times superior.

On a geological scale, that's an almost instantaneous disappearance. Will our children be able to escape this "ecological supernova"? Since young Severn Cullis-Suzuki's heart-rending call, which enjoined adults to "stop breaking what they don't know how to fix" at the Rio Summit 20 years ago, "ecodiplomacy" has made some progress. But will the slow rhythm of these negotiations adapt to the lightening speed of biological collapse?

What now?

No less than 500 international and multilateral conventions on the environment were born from the large political meetings on biodiversity, climate and biology: on humid areas (Ramsar, 1971), the preservation of wildlife, the commerce of flora and fauna on the brink of extinction (Cites, 1973), the protection of world heritage (Unesco, 1972), the conservation of wildlife and natural habitats in Europe (Berne, 1979), migrating species, cetaceans, ecological corridors, hunting exclusion zones, biological diversity, the fight against desertification, tropical forests…

But without a world organization to head it all, the efficiency of all of these agreements is diluted. So what can we do? The scientists, who don't usually bother with politics, suggest bold answers to save what can be saved, by associating the paradoxes of "degrowth" (aligning planetary standards of living with a more reasonable consumption of resources) and "innovation" (developing new technologies to produce and distribute new food and energy riches without consuming more territory).

A more radical trend suggests we force humanity to be more humble. The authors of the "Nature" study, who say they are not worried but "terrified by their own results," believe humanity has no other choice than to start a real revolution in its lifestyle: it has to reduce the demographic pressure, rethink its social structures and concentrate populations in areas that are already dense to give Earth the means of reaching its natural equilibrium again.

Read the original article in French.

Photo - amneziak