Warming of 1.5 degrees reached in 2030, unprecedented increase in extreme weather events, end of fossil fuels, "unequivocal human responsibility", irreversible rises in water levels, forests that absorb less CO2 ... the report of experts from the UN on the climate presented Monday is very alarmist on the future of the planet.

Worse and faster than feared.

Global warming could reach the threshold of + 1.5 ° C around 2030, ten years earlier than estimated, threatening new disasters "unprecedented" humanity, already hit by heat waves and floods in series.

Less than three months before the COP26 climate conference in Glasgow, the shocking report of the UN climate experts (IPCC) published on Monday sounds like a commotion: humans are "indisputably" responsible for climate disturbances and 'have no choice but to drastically reduce greenhouse gas emissions, if they want to limit the damage.

+ 1.5 degrees from 2030, ten years earlier than expected

This first assessment report for seven years, adopted Friday by 195 countries, reviews five scenarios of greenhouse gas emissions, from the most optimistic - some would say utopian - to the worst case scenario. In any case, the planet should reach the threshold of + 1.5 ° C compared to the pre-industrial era around 2030. Ten years earlier than the previous estimate of the IPCC in 2018.

Then, by 2050, the increase would continue well beyond this threshold - which is one of the key limits of the Paris Agreement - even if the world succeeds in sharply reducing greenhouse gas emissions.

And if these emissions are not drastically reduced, the + 2 ° C will be exceeded during the century.

This would signify the failure of the Paris Agreement and its objective of limiting warming "well below" + 2 ° C, if possible + 1.5 ° C.

Current fires, floods, heat waves are only a "first burst"

While the planet has gained + 1.1 ° C for the moment, the world is seeing with its own eyes the consequences already at work. Even more this summer, with the images of flames ravaging the American West, Greece or Turkey, waves overwhelming regions of Germany or China, or a thermometer approaching 50 ° C in Canada. "If you think this is serious, remember that what we are seeing today is just the first salvo," comments Kristina Dahl of the Union for Concerned Scientists.

Even at + 1.5 ° C, heatwaves, floods and other extreme events will increase in an "unprecedented" way in terms of magnitude, frequency, time of year they strike and areas affected, warns the IPCC.

"This report should shudder anyone who reads it (...) It shows where we are and where we are going with climate change: in a hole that we continue to dig," commented climatologist Dave Reay .

"This report must spell the end of coal and fossil fuels"

Faced with this apocalyptic future, calls for action are multiplying. "Stabilizing the climate will require a strong, rapid and lasting reduction in greenhouse gas emissions, to achieve carbon neutrality", insists Panmao Zhai, co-chair of the group of experts that developed this first part of the IPCC assessment.

The second part on the impacts, scheduled for February 2022, shows in detail how life on Earth will inevitably be transformed within 30 years, if not sooner.

The third component on solutions is expected in March.

But the way forward is already widely known to put in place the transition to a low-carbon economy.

"This report must sound the death knell for coal and fossil fuels before they destroy our planet", pleaded UN Secretary General Antonio Guterres, accusing these energies and deforestation "of suffocating the planet".

A decisive COP 26 in Glasgow

While it would be necessary to reduce CO2 emissions by half by 2030 to maintain the + 1.5 ° C, all eyes are now on Glasgow where leaders from around the world will meet in November.

"There is no time to wait and no room for apologies", insisted Antonio Guterres, demanding that the COP be a "success", after this "red alert for humanity" launched by the IPCC .

But at this point, only half of governments have revised their greenhouse gas emissions commitments.

The previous series of commitments, made in the wake of the Paris Agreement of 2015, would lead to a world at + 3 ° C, if they were respected, but at the current rate, the world is heading more towards + 4 ° C or + 5 ° C.

The "irreversible" rising waters

In the midst of its gloomy projections, the IPCC nevertheless brings a hope to which to cling to. In the best scenario, the temperature could drop below the 1.5 ° C threshold by the end of the century, drastically cutting emissions and absorbing more CO2 than is emitted. But the techniques for recovering CO2 from the atmosphere on a large scale are still in the research stage, notes the IPCC.

And some consequences of global warming are "irreversible" anyway, the report insists.

Under the influence of the melting polar ice, the level of the oceans will continue to rise for "centuries, even millennia".

The sea, which has already gained 20 cm since 1900, could still rise by about 50 cm by 2100, even at + 2 ° C.

"It seems a long way off, but millions of children already born should still be alive and well in the 22nd century," said Jonathan Bamber, one of the authors of the report.

Fighting scientists and activists

For the first time, the IPCC also underlines "not being able to exclude" the occurrence of "tipping points", such as the melting of the Antarctic ice sheet or the death of forests, which would lead the climate system towards a dramatic change. and irremediable.

But this is not a reason to give up the fight, on the contrary, insist scientists and activists.

Because climate change does not magically unleash itself at a certain threshold: every fraction of a degree counts and reinforces the impacts.

"We are not doomed to failure," says Friederike Otto, one of the authors.

"We will not let this report be put on a shelf," insists Kaisa Kosonen of Greenpeace.

"We will bring it with us to the courts."