Oceans poised to become our worst enemy, warns UN

The oceans, sources of life on Earth, could become our worst enemies on a global scale if nothing is done to put a brake on greenhouse gas emissions, according to a draft report obtained exclusively by AFP.

Fish stocks could decline, the damage caused by cyclones could multiply and 280 million people would be displaced because of rising sea levels. And this on the optimistic assumption that global warming would be limited to 2 ° C compared to the pre-industrial era, according to this special report of the Intergovernmental Panel on Climate Change (IPCC), on the oceans and the cryosphere (pack ice, glaciers, polar ice caps and permanently frozen ground), which will be officially unveiled on September 25 in Monaco.

This rich 900-page document is the fourth UN special report issued in less than a year. The equally alarming precedents concerned the goal of limiting global warming to 1.5 ° C, biodiversity and land management and the global food system.

With the expected increase in the frequency of cyclones, many megacities close to the coast but also small island nations would be flooded every year from 2050, even in optimistic scenarios.

"When you observe the political instability triggered by small-scale migrations, I tremble when I think of a world where tens of millions of people should leave their lands swallowed by the ocean"worries Ben Strauss, chairman and CEO of Climate Central, a research institute based in the United States.

Up to 99% of permafrost threatened

The report also predicts that 30% to 99% of permafrost, the ground layer theoretically frozen all year round, melts by 2100, if greenhouse gas emissions continue at the current rate.

The permafrost of the northern hemisphere will release under the effect ofcarbon bomb"made of carbon dioxide (CO2) and methane (CH4), accelerating warming.

Multiplication of floods

Phenomena already underway could also lead to a steady decline in fish stocks, on which many people depend for their food. The damage caused by the floods could be multiplied by 100, even up to 1000 by 2100.

The melting of glaciers caused by global warming will give too much fresh water, then too little, to billions of people who depend on it, also points a "summary for decision makers"will be discussed line by line by representatives of IPCC member countries, meeting in Monaco from 20 September.

According to the report, sea level rises in the 22nd century "could exceed several centimeters a year", about a hundred times more than today.

If the temperature rise is 2 ° C in 2100, it will be the beginning of a "run forward"In the rise of the seas, warns Ben Strauss.

The release of the report will come after a world climate summit convened by UN Secretary-General Antonio Guterres in New York on 23 September. It wants stronger commitments from countries to reduce their CO2 emissions, while at the current pace, they would lead to a global warming of 2 to 3 ° C by the end of the century.

Experts fear that China, the United States, the European Union and India – the four main emitters of greenhouse gases – are coming up with promises that are not up to the challenges.