Has the Earth entered the sixth mass extinction?

This global badessment is the first in nearly 15 years: 150 experts from 50 countries worked for three years and collected thousands of biodiversity studies.

Its 1,800-page report will be submitted Monday to the 130 member states of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), which will be discussed point by point.

"The global environmental heritage – the land, the oceans, the atmosphere and the biosphere – on which humanity depends is being changed to an unprecedented level, with cascading impacts on local and regional ecosystems ", says the draft synthesis. report obtained by AFP, which can be modified.

Drinking water, air, insect pollinators, CO2-absorbing forests … The findings concerning these resources are as alarming as the latest report of the Intergovernmental Panel on Climate Change (IPCC), which in light, last year, growing gap greenhouse gas emissions and the goal of limiting climate change and its catastrophic effects.

The text also links biodiversity loss to global warming, insofar as these two phenomena are accentuated in part by the same factors, such as agricultural practices and deforestation, responsible for about a quarter of CO2 emissions but also serious damage to ecosystems.

The exploitation of land and resources (fishing, hunting) is the main cause of biodiversity loss, followed by climate change, pollution and invasive species. The result is "a rapid and imminent acceleration of the extinction level of the species", according to the project. Of the estimated 8 million species on the planet, including 5.5 million insects, "between 500,000 and one million will be at risk of extinction, many of them over the next few decades".

These projections correspond to the warnings of many scientists who believe that the Earth is at the beginning of the "6th mbad extinction" and the first since man inhabits the planet.

But several sources close to the negotiations regretted that the draft summary is not as clear and does not mention this mbad extinction.

"There is no doubt that we are moving towards the sixth mbad extinction, and the first man-made," Robert Watson, president of IPBES, told AFP recently. "But it's not something that the public can easily see."

For there to be an awareness, "we must tell them that we are losing insects, forests, charismatic species".

In addition, "governments and the private sector must start taking biodiversity seriously, as well as warming," the scientist insisted.

One year ahead of the scheduled meeting in China of the member states of the United Nations Convention on Biological Diversity (COP15), many experts expect the IPBES report to be a crucial step towards major agreement like the one signed in Paris in 2015 against climate change. WWF hopes that COP15 will set "high level goals".

"If we want a sustainable planet in 2050, we must have a very aggressive target by 2030," said Rebecca Shaw, chief scientist of the NGO. "We need to change course in the next 10 years, as with time."

But since global warming remedies that involve major changes in the production and consumption system are already causing great resistance, what will happen to biodiversity?

"It will be even more difficult because people are less aware of biodiversity issues," said Jean-François Silvain, president of the French Foundation for Biodiversity Research. "You must be lucid."

The main "mbad extinctions" on Earth

Many scientists believe that the Earth is at the beginning of a new "mbad extinction" marked by the disappearance of species at an alarming rate, mainly due to the action of the human .

But this is not the first: over the last 500 million years, the planet has seen five episodes in which at least half of all living things have been eradicated in the blink of an eye , from the point of view of geological history.

In total, more than 90% of the organisms that walked, swam, fly or crawl disappeared.

Here are the five mbad extinctions recorded:

When: about 445 million years ago

Disappearance of species: 60-70%

Probable cause: short but intense ice age

At that time, life was mainly in the oceans. Experts believe that the rapid formation of glaciers has frozen most of the world's waters, causing sea levels to drop. Marine organisms such as sponges and algae are the most affected, as are molluscs and cephalopods. primitive and jawless fish called ostracoderms.

When: between 360 and 375 million years old

Disappearance of species: up to 75%

Probable cause: Oxygen depletion in the oceans

Marine organisms are once again the most affected. Fluctuating ocean levels, climate change or the impact of an asteroid are considered to be responsible. One theory is that the proliferation of terrestrial plants would have led to anoxia (lack of oxygen) in surface waters. Trilobites, arthropods from the bottom of the oceans, would have been the main victims.

When: about 252 million years ago

Disappearance of species: 95%

Probable causes: asteroid impacts, volcanic activity

Considered the "mother of all extinctions", this biological crisis has devastated the oceans and lands. It is also the only one in which all insects have virtually disappeared. Some scientists believe that it has happened over millions of years, others only 200,000 years.

The trilobites that had survived the first two extinctions have completely disappeared, as well as sharks and fish with bones. On the ground, moshops, herbivorous reptiles several meters long, have also disappeared.

When: there are about 200 million years

Disappearance of species: 70-80%

Probable causes: multiple, the debate is still open

The mysterious extinction of the Tribadic has eliminated many large terrestrial species, most of which are archosaurs, ancestors of dinosaurs and descendants of modern birds and crocodiles. Most large amphibians have also disappeared.

One theory deals with mbadive lava eruptions during the fragmentation of Pangea, the last supercontinent, with eruptions accompanied by huge amounts of carbon dioxide that caused a galloping global warming. Other scientists indicate asteroids, but no corresponding crater was identified at that time.

When: about 66 million years ago

Disappearance of species: 75%

Probable cause: impact of an asteroid

The discovery of a huge crater of the current Mexican peninsula of Yucatán corroborates the hypothesis that the impact of an asteroid would be at the origin of the disappearance of dinosaurs non-avian such as T-Rex and triceratops.

But most mammals, turtles, crocodiles, frogs and birds have survived, as well as marine life.

Without the dinosaurs, mammals have multiplied, resulting in the birth of homo sapiens, a species at the origin of a probable sixth extinction.