Climate change: oceans increasingly hot, high and acidic

Climate change: oceans increasingly hot, high and acidic

The oceans reached the hottest and most acidic levels on record in 2021, while the melting of the ice caps is accelerating the rise in sea level, underlines the World Meteorological Organization (WMO) in a report published on Wednesday May 18. .

In its annual report on the state of the global climate, the WMO highlights the extreme phenomena to which the world’s oceans are subjected due to the increasingly marked effects of climate change. “Our climate is changing before our very eyes. The heat retained by man-made greenhouse gases will warm the planet for many generations to come”WMO Secretary-General Petteri Taalas said in a statement.

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The WMO report follows the latest report from the United Nations Intergovernmental Panel on Climate Change (IPCC), which warns that humanity will face increasingly catastrophic consequences. of climate change if it does not drastically reduce its greenhouse gas emissions. Levels of carbon dioxide and methane, which cause the atmosphere to warm, hit new record highs in 2021, the WMO points out.

#Climatechange affects everyone and everything on the planet
Greenhouse gas levels, ocean heat and acidification, sea level rise at record levels in 2021
We can still limit the damage#ClimateActionNow for the sake of future generations#StateofClimate

— World Meteorological Organization (@WMO) May 18, 2022

The only +1.5° soon to be exceeded?

Globally, the average temperature last year was 1.11°C higher than the pre-industrial average, close to the 1.5°C threshold above which experts expect natural disasters are on the rise. This average temperature was a little lower than in 2020 thanks to the cooling caused by the La Nina phenomenon in the Pacific Ocean, but the UN experts consider it probable that the threshold of 1.5°C will be exceeded, at the least temporarily, over the next five years. “It’s only a matter of time before we see another hottest year on record”, notes Petteri Taalas. The oceans bear a large part of the burden of global warming and emissions. Bodies of water absorb about 90% of the Earth’s accumulated heat and 23% of carbon dioxide emissions from human activity.

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According to the report, the oceans have warmed at a particularly high rate over the past 20 years and have never been warmer than in 2021, since such measures have existed. However, this evolution is almost irreversible since it would probably take centuries or even millennia to return to previous temperatures. The acidity of the oceans has also reached its highest level for at least 26,000 years, as they absorb more carbon dioxide from the atmosphere. As a result of all these changes, sea levels have risen by 4.5 centimeters over the past ten years, twice as much as during the previous decade. At the same time, extreme heat waves, forest fires, floods and other climate-related disasters are also increasing on land, underlines the WMO report, which already estimates the cost at more than 100 billion dollars. .

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