Earth: change of epochs («Liberation», France)

According to the journal «Nature», the human impact on the environment will lead the planet to the point of change. The last time this was 12,000 years ago

Photo: EPA

Usually the end of the world Hollywood is in the form of a giant meteorite disaster or nuclear war. The form, which is presented in a study published in the scientific journal Nature (1), has never been so like a human hand. Not the one that presses the red button, but the one that is the combined image of all people, putting pressure on ecosystems. The article, written in June, an international multi-disciplinary team of two dozen scientists, says plainly: we are leaps and bounds closer to the inevitable and irreversible collapse of the ecosystems on which we depend on human civilization. If they are destroyed, our future will be in the extreme foggy. Some of the researchers admit that their "appalling" own conclusions.

Unknown. Biosphere on the threshold of change of state, a kind of collapse in the dark. Several phenomena are superimposed express the loss of biodiversity, increased incidence of climatic disasters, rapid changes in production and consumption of energy flows … "When changing the way the functioning of the ecosystem, there is what is called a change in the state, says David Bruno (Bruno David) from the laboratory biogeonauki CNRS (National Centre for Scientific Research) in Dijon. Now we are on the threshold of one of these dramatic changes. "

During past crises, radical changes were caused by the Earth's biogeochemistry, volcanic eruptions or gigantic meteorites. This time, the researchers called the cause of human rights. According to the group paleoecology Barnoski Tony (Tony Barnosky), which is coordinating the work of researchers, we are "powerful enough" to change the conditions of life on Earth, radically changing the ecosystem and the local climate. "Simply put, state of accelerated human behavior and its needs," — says Steve Carpenter (Steve Carpenter) from the University of Wisconsin.

These state changes may be small and local, confined to the limits of the lake, pond … "They are, we understand quite well. But the biggest point of the change is difficult to determine, "- says Marten Scheffer (Marten Scheffer), a pioneer of research in this area. Importantly, Shaffer is not sure what will happen only one point changes. "In the past there have been enormous changes the point, they have now. The difference is that today we see them coming … "

State change cause two things: the effect of the threshold or mass effect. The first is difficult to predict, since the critical threshold is reached gradually, and we never know in advance the degree of criticality. But the effect of mass is never a surprise, for example, in the case of forest destruction by bulldozers. But people change the composition of native species and ecosystem functions, causing small-scale changes that are combined with each other, forming a chain of events leading to a global change.

Ricochet. According to the team Barnoski the cause of the problem is primarily a change in the type of land use, and only then — climate change. Throughout its history, humanity has changed 43% of the land, destroying the forest to develop in their place, intensive agriculture, eliminating the natural space to build on their city. "This rebound has affected almost all of the remaining surface of the earth: a third of drinking water is diverted for human use, and 20% of what makes the land is given to the man," — says Barnoski.

On the planet this is not the first time. Changes occurred on coral reefs and in the Sahara desert, which was a fertile area with lush vegetation is 5500 years ago. But what says the team from Berkeley, will change very sharp: the worst change can happen in this century, possibly until 2050. "The evidence is that quite evident. We can not ignore some of the biological realities "- insists Barnoski. Usually, changes in the state develop over thousands, even millions of years. For 500 million years the Earth has experienced five major crises that led to the five mass extinctions on our planet. The last time was 65 million years ago and led to the death of the dinosaurs. Another example: 12 000 years ago, the transition from glacial to interglacial periods lasted a thousand years. Since then, the climate in the global sense, Stubley, allowing a person to develop to such an extent that he was able to go to the moon.

What will happen next? Perhaps we will see a mass movement of species to the uninhabited parts of the Earth, a huge loss of biodiversity, new habitats, and — why not — tropical forests in Antarctica. "The last time this happened 12,000 years ago, disappeared half mammals weighing more than 50 kg," — says Barnoski. "Changes in the state are fraught with a lot of surprises, but we know about them is enough to realize that the world will be very different from what it was in the past 11,000 years — he warns. — And we are in the world of 7 billion, probably feel it for yourself. "

Category: Scientists, experts, science

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