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, damage from cyclones multiply and 280 million people would be displaced due to rising sea levels, says special report by the Intergovernmental Panel on Climate Change (IPCC) ), on the oceans and the cryosphere (ice floes, glaciers, polar ice caps and permanently frozen ground), which will be officially unveiled on September 25 in Monaco.
The 900-page document is the fourth UN special report published in less than a year. The equally alarming precedents concerned the objective of limiting global warming to 1,5 ° C, biodiversity and the management of the land and the world food system. According to this fourth installment, which compiles existing scientific data and is seen as a reference, rising sea levels could ultimately displace 280 million people around the world. And this in the optimistic hypothesis where global warming would be limited to 2 ° C compared to the pre-industrial era.
With the foreseeable increase in the frequency of cyclones, many mega-cities close to the coasts but also small island nations would be hit by flooding every year from 2050, even in optimistic scenarios. "When you observe the political instability triggered by small-scale migration, I tremble at a world where tens of millions of people are expected to leave their lands swallowed by the ocean", worries Ben Strauss, president and director. from Climate Central, a US-based research institute.
The report further predicts that 30% to 99% of permafrost, the soil layer theoretically frozen all year round, will melt by 2100, if greenhouse gas emissions continue at the current rate. The permafrost of the northern hemisphere will release under the effect of the thaw a "carbon bomb" made of carbon dioxide (CO2) and methane (CH4), accelerating warming.
Phenomena, already underway, could also lead to a continued decrease in fish stocks, on which many populations depend for food. The damage caused by flooding could be multiplied by 100, even up to 1.000 by 2100. The melting of glaciers caused by global warming will give too much fresh water, then too little, to billions of people who have it. depend, also points to a provisional "summary for decision-makers" which will be discussed line by line by the representatives of the member countries of the IPCC, meeting in Monaco from September 20.
Reluctance of the main emitters
According to the report, sea level rises in the 22nd century "could exceed several centimeters a year", about a hundred times higher than today. If the temperature increase is 2 ° C in 2100, it will be the start of a "race forward" in the rising seas, warns Ben Strauss.
The publication of this report will come after the holding in New York on September 23 of a world climate summit convened by the Secretary-General of the United Nations, Antonio Guterres. He wants to obtain stronger commitments from countries to reduce their CO2 emissions when at the current rate, they would lead to 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 - will arrive with promises that are not up to the stakes. So, across the Atlantic, observes Michael Mann, director of the Earth System Science Center at the University of Pennsylvania, "techno-optimists still believe that ways can be found to solve this problem", even as "the United States United are not prepared to face a one meter rise in sea level by 2100 ″ for some of their cities like New York and Miami.
Of the four major economic regions accounting for nearly 60% of emissions from fossil fuels, none seems ready to announce more ambitious targets to reduce emissions from their economies. Donald Trump puts down the climate policy of his predecessor Barack Obama and wants the United States to leave the Paris Agreement of 2015. An agreement that aims to keep the average temperature increase well below 2 ° C compared to at pre-industrial levels, and as much as possible at 1,5 ° C. India, for its part, is rapidly developing solar energy but continues to increase its coal capacities. The European Union is moving towards a carbon "neutrality objective" to be reached by 2050 but several Member States are reluctant to commit.
China, which emits almost as much CO2 as the United States, the European Union and India combined, is sending mixed signals. “Beijing's attention is gradually shifting away from environmental issues and climate change,” said Li Shuo, analyst for Greenpeace International. He explains it by concern over the slowdown in the Chinese economy and the trade war with the United States. Shanghai, Ningbo, Taizhou and half a dozen major Chinese coastal cities are highly vulnerable to future sea level rise, which is expected to rise one meter above the aggregate level at the end of the 2th century if sustained. of COXNUMX emissions