The oceans have absorbed more than 90% of the excessive heat trapped by greenhouse gases since 1971 and are already undergoing “changes that will be irreversible in the coming centuries”, warned the World Meteorological Organization (WMO) today.
This is one of the conclusions of the WMO report on the state of the climate in the southwest Pacific in 2023, presented in Tonga by the organization's secretary, Celeste Saulo, and the UN secretary-general, António Guterres, who is visiting to the country during the 53rd summit of the Pacific Islands Leaders Forum.
The island paradises of the Pacific are in danger from the “overflowing” of the ocean, Guterres said, as average seas around the world rise at unprecedented speed. But the problem “is coming to all of us, along with the devastation of fishing, tourism and the blue economy”, said the United Nations leader.
The UN Secretary-General also warned of the real threat of a melting of ice in Greenland and western Antarctica, which would endanger agglomerations such as Los Angeles, Lagos and the Asian megacities of Shanghai, Mumbai and Dhaka.
Guterres thus referred to the impact of the climate crisis on rising sea levels during a speech in the oceanic archipelago of Tonga, as part of the summit of leaders of the Pacific islands, which are among those most threatened by climate change.
Having made the climate crisis one of the flagships of his mandate, the UN Secretary-General took it for granted that there will be a one meter rise in sea levels, but insisted that “the scale, pace and impact” of this depends on human action. increase.
The WMO report indicates that the melting of ice in Greenland and the poles, added to the high absorption of global warming by the oceans, is adding water to the large masses of the planet, which in turn increase their temperature and expand, leading to an increase in their levels.
“The upper 2.000 meters of the ocean are expected to continue to warm due to excessive heat accumulated in the Earth system by global warming, a change that is irreversible on time scales of centuries and millennia,” the report states.
The Pacific islands are on the “front line” of the climate crisis due to their high exposure to the effects of gas emissions – to which they practically do not contribute –, including tropical cyclones and floods, and phenomena such as a volcanic eruption that generated a tsunami and strong steam production in 2022.
“Human activities have weakened the ocean’s ability to sustain and protect us and – through rising sea levels – are turning a longtime friend into a growing threat,” lamented the WMO.
“We are already seeing more coastal flooding, shoreline retreat, contamination of freshwater reserves by saltwater and displacement of communities,” he added.
Between 1993 and 2023, the median global sea level rise was 9,4 centimeters (cm), but in the tropical Pacific it was more than 15 centimeters in some places. In a scenario of warming of three degrees Celsius (in line with the current trajectory), sea levels in the region could rise by another 15 cm between 2020 and 2050.
Among the consequences of global warming, which organizations have urged to halt immediately, is not just rising sea levels: also greater intensity and frequency of marine heat waves, more heat at the surface and in ocean contents, and more acidification . Each phenomenon with its own ramifications.
“There are growing concerns that some island nations may become uninhabitable,” the document warns, “with implications for their relocation, sovereignty and statehood.”
“Deep, rapid and sustained cuts in global greenhouse gas emissions are needed NOW to remain on a long-term warming trajectory of 1,5 degrees,” urges the report, which considers it necessary to improve coastal adaptation and invest in resilience all over the world, especially on small islands.
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