Even if it may seem counter-intuitive, the water of the seas and the oceans is not perfectly chemically speaking. With an average pH of around 8.1, it is a slightly alkaline (The reverse of acid in the jargon of chemistry).
This property, which is partly due to the presence of dissolved salts and minerals, is absolutely crucial from an ecological point of view. Marine life as we know it has evolved under these conditions for millions of years, and many marine organizations – from corals to molluscs, including microscopic plankton – are extremely sensitive to pH changes. The slightest variation, even minimal, can disturb vital processes such as the formation of shells and limestone skeletons, with very concrete implications for all other living species.
Ocean acidification, a major problem
However, since the beginning of the industrial era, human activities have rejected massive quantities of CO₂ in the atmosphere. An important part of this carbon dioxide is absorbed by the oceans. In contact with seawater, this CO₂ turns into carbonic acid, which gradually lowers the pH of the oceans and makes them more and more acidic.
This trend is extremely worrying for specialists, because the oceans play a role of crucial stabilizer for the entire biosphere. Many statistical models demonstrate that beyond a certain acidification threshold, marine ecosystems will simply no longer be able to take these changes. We therefore find ourselves under the threat of a real ecological disaster, marked by the disappearance of coral reefs, the decline of plankton which produces half of our oxygen … and, in the long term, The collapse of several major systems essential for the survival of all living beings.
And unfortunately, this is precisely what is happening right now. According to the report of the institution, the pH on the surface of the oceans has now dropped by approximately 0.1 unit on a global scale. It might seem anecdotal, but it must be taken into account that the pH is measured on a so -called logarithmic scale: this variation is in fact corresponding to a increase of 30 to 40 % of aciditywhich is enormous.
« The trend we observe goes in the wrong direction. The ocean acrifies, oxygen levels decrease and sea heat waves multiply. This increases the pressure on a vital system to stabilize the conditions on planet earth “Comments Levke Caesar, the main co-author of the report. “” The consequences have repercussions on food security, the stability of the world climate and human well-being She adds.
A seventh “planetary limit” now exceeded
The crossing of this ocean acidification threshold marks a disturbing turning point: it is now the seventh “planetary limit” on new to be exceeded. These limits, defined by the scientific community, represent the processes that regulate the stability and resilience of the earth. Together, they somehow form the vital support system of our planet – a set of thresholds not to be crossed if we want to maintain conditions conducive to human life and the development of our societies.
On their own, this data is therefore already highly worrying. But above all, they are part of a broader context, relating to what researchers call ” planetary limits ».
This term designates a set of fundamental, interconnected processes, which all contribute to maintaining the ecological stability of our planet. The acidification of the oceans is one of them, and there are eight others:
-
the climate changein particular represented by the concentration of CO₂ in the atmosphere,
-
The integrity of the biosphereembodied by the level of biodiversity and the extinction of species,
-
Earthly system changeslike deforestation and exploitation of soil,
-
The use of fresh water (samples in rivers, lakes and aquifers),
-
Biogeochemical flows (disruption of nitrogen and phosphorus cycles by intensive agriculture),
-
New entities (Introduction of chemical pollutants, plastic and other synthetic substances),
-
the impoverishment of the stratospheric ozone layer which protects us from UV radiation,
-
and finally the Atmospheric aerosol levelsassimilated to pollution with fine particles.
With these new data on ocean acidification, we have now exceeded seven of these nine critical thresholds. Only atmospheric aerosol levels and the integrity of the ozone layer remain within the limits deemed acceptable. A clear sign that we are now Closer to a large -scale ecological collapse than a return to a lasting balance.
« Not fatality »
But that does not mean that the situation is already desperate. Some significant examples recall that the international community is capable of real exploits when it acts quickly to correct errors that directly threaten its existence. We can cite the Ozone layer soap operawhose impoverishment could have cost humanity very dearly if it had not been contained thanks to decisive initiatives such as the Montreal Protocol.
The challenge will therefore be do the same with other planetary limitsbefore crossing a real point of no return.
« We are witnessing a widespread decline in the health of our planet. But it is not inevitable » » » hammers Johan Rockström, manager of the PIK. . Even if the diagnosis is serious, the healing window is still open. Failure is not inevitable; It’s a choice. A choice that must, and can be avoided. »
🟣 To not miss any news on the Geek newspaper, subscribe to Google News and on our WhatsApp. And if you love us, .
