The World Meteorological Organization, which depends on the UN, published its annual report on Wednesday. “The time is counted for us“, warns Antonio Guterres, the Secretary General of the UN. According to this report, the degradation of the climate is installed. The concentrations of carbon dioxide or methane continue to climb. There is a 150% increase in CO2 compared to the pre-industrial era. As a result, global warming, which contributes to coral bleaching, has reached a record level. The rise in sea levels is accelerating.
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A less known but equally bad phenomenon for the environment, the acidification of the seas is also reaching a high level. “Acidity has increased by 30% in the oceans since the pre-industrial era“, underlines Wednesday May 18 on franceinfo Denis Allemand, director of the scientific center of Monaco. This acidity affects corals, underlines this researcher, specialized in comparative physiology and marine ecophysiology. The expert recalls that corals are at the origin of 30 % of all life in the oceans.”So if these reefs were to disappear, we would see 30% of fish and other invertebrates disappear from the oceans. It’s catastrophic“, he warned on franceinfo.
franceinfo: The rise in sea levels is accelerating, and so is their acidification. What is this acidification of the waters due to?
Dennis German: It is simply the consequence of the increase in carbon dioxide in the air. The CO2 which increases in the air, because of human activities, will dissolve in particular in water and it makes acid. And so the acidity of the oceans is increasing significantly, +30% since the pre-industrial era. This has an effect on the physiology of organisms, especially those that make skeletons like molluscs, corals. They therefore have much more difficulty in making these skeletons, which are nevertheless very important.
Then there are reactions on the food chain?
Corals are surely the organisms most affected by these events, apart from they are the source of 30% of all the life in the oceans. So if coral reefs were to disappear, we would see 30% of fish and other invertebrates disappear from the oceans. It’s catastrophic !
All the seas of the globe are concerned?
Acidification, like global warming, affects all the seas of the globe, it is a general effect. Now, the coasts are even more concerned because in addition to global activity, there is local pollution linked to population density. So all these ecosystems that are near the coast, which are also the most productive such as seagrass beds and coral reefs, are actually the most subject to this action.
The rise in temperature also has an impact?
This increase is creating the disappearance of the first ecosystem on the planet: coral reefs. A few years ago, canaries were used in mines to warn of the presence of CO2. Coral reefs are the equivalent: it is an ecosystem that is showing that the oceans are suffering and disappearing little by little. Unfortunately, we don’t really see them in front of our eyes and that’s maybe why we don’t worry. The increase in temperature creates this bleaching phenomenon, that is to say the loss of symbiosis between the coral, an animal, and the algae that feed it. Without these algae, they disappear. The Great Barrier Reef, the largest structure in the world, is suffering from this bleaching. 91% of its reefs have been affected this year by this phenomenon, it is catastrophic.