Folha's most likely reader, as well as three quarters of the Brazilian population, does not live in a coastal region. That is why it is unlikely to make a note – but it should – of the risks it has with the impact of the climate crisis on the oceans, the subject of a scientific report released Wednesday.
All populations on Earth depend on the sea in one way or another. This is the central message of “The Ocean and the Cryosphere in a Changing Climate” by IPCC (Intergovernmental Panel on Climate Change), an agency created in 1988 to report on the state of the art of climate research.
The text, known by the acronym SROCC, completes the study trilogy commissioned from the IPCC in 2016, following the Paris Agreement. The first contemplated consequences of not limiting the heating to 1.5ºC, as recommended by the treaty (1ºC is gone); the second, impacts of land uses (agriculture, livestock and forests); now oceans.
To have any chance of not crossing this threshold, it would be necessary to cut fossil fuel combustion by at least half by 2030. Last year, it is estimated that they increased by 2.7%. At this point, at the end of the century there may be between 2.9ºC and 3.4ºC of heating.
Seas cover 71% of the planet's surface and absorb 90% of that heat added to the atmosphere with global warming. Without their service, we would be fried and roasted.
Heated liquids expand, one still learns in elementary school. As they absorb heat, the oceans increase in volume, and their average level rises.
Warmer waters provide energy for tropical cyclones (hurricanes and typhoons), making them more frequent at full force (5), as in 2018. In addition, they force the migration of marine species important for fishing, which provides 17% of the animal protein consumed on Earth.
There is another factor contributing to the rising sea: melting of terrestrial glaciers, which rest on Antarctica, Greenland and mountain ranges, such as the Andes. This component, reports the SROCC, has already surpassed thermal expansion as a motor for rising ocean waters, accelerating it.
At the current rate of release of carbon (greenhouse gases) into the air, the oceans will rise to 1.1 m over the next 80 years. It may seem little to those who live more than 700 m above sea level, like the Paulistanos, but it has disastrous effects on the coastal population, their properties and those responsible for their infrastructure.
Ask an inhabitant of Santos (SP) what is happening in Ponta da Praia, as shown in a report from the Climate Crisis series in June 2018.
There are 680 million people on the planet, almost one tenth of the world's population, living in areas vulnerable to marine erosion and increasingly destructive weather tides (hangovers).
There is more, however. Oceans also absorb part of carbon dioxide (CO2, the main greenhouse gas) and their waters become more acidic. A lethal threat to limestone-forming organisms and coral colonies, such as the Great Barrier in Australia and Abrolhos in Brazil, a stronghold of great biodiversity.
Another 670 million people live in mountainous areas and rely on disappearing glaciers for water, irrigation and livestock. This is the case of most of Peru's population, which, moreover, relies on ocean fishing for both food and exports.
In addition to terrestrial glaciers, global warming is affecting sea ice platforms as well as sea ice. This last, less thick layer, which expands in winter and shrinks in summer, shrinks rapidly in the polar oceans. Arctic and the Austral.
At the North Pole, where there is no continent, only ice over the sea, setback takes a dramatic pace. The two smallest surface records in September (northern summer) took place this decade, in 2012 and 2019 – say, right now.
They are crucial parts of the cryosphere for climate and weather, for example in southern and southeastern Brazil. A drastic change in rain patterns, winds and temperature around here would no doubt attract more attention to what happens in the more distant oceans. But by then it would be too late.
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