Report: World oceans approaching critical acidification level

The world’s oceans are on the verge of becoming too acidic to adequately support marine life or help stabilize the climate, according to a new report on Monday.

The report by the Potsdam Institute for Climate Impact Research (PIK) describes nine factors that are crucial for regulating the viability of our planet.

In six of these areas, the limit has already been exceeded as a result of human activities in recent years.

The critical threshold for ocean acidification could soon be the seventh to be exceeded, according to PIK’s first Planetary Health Check.

The safe limits that have already been exceeded concern crucial – and related – factors such as climate change, the loss of natural species, natural habitat and freshwater, and an increase in pollutants, including plastics and chemical fertilizers in agriculture.

The sustainable level of ocean acidification is also likely to be exceeded, mainly due to ever-increasing carbon dioxide emissions (CO₂) produced by the combustion of fossil fuels such as oil, coal and gas.

“As CO₂ emissions are increasing, more of it is dissolving in seawater… and the oceans are becoming more acidic,” Boris Sakschewski, one of the lead authors, told reporters.

“Even with rapid emission reductions, some persistent acidification due to CO₂ greenhouse gases already emitted and the time it takes for the ocean system to respond,” he explained.

“It therefore seems inevitable that the ocean acidification limit will be exceeded in the coming years.”

Turning points

Acidic water damages corals, shellfish and the phytoplankton that feed many marine animals.

This also means disrupting food supplies for billions of people and limiting the oceans’ ability to absorb more CO2.₂ and thus contribute to limiting global warming.

The only one of the nine planetary boundaries that is not close to being exceeded concerns the state of the planet’s protective ozone layer.

Man-made chemicals damaged this protective shield and caused acid rain, but since a number of these chemicals were banned in 1987, it has begun to recover.

A ninth limit value – it concerns the concentration of tiny particles in the atmosphere that can cause heart and lung diseases – is close to the danger limit.

However, the researchers say there are signs of a slight decline in the risk due to efforts by several countries to improve air quality, such as banning the most polluting petrol and diesel cars.

However, they warned that particulate matter concentrations could still rise sharply in countries with rapid industrialization.

PIK has established these nine planetary danger levels to warn humanity against tipping the Earth’s natural systems beyond a point of no return.

“If these tipping points were exceeded, it would have irreversible and catastrophic consequences for billions of people and many future generations on Earth,” they said.

All nine planetary boundaries are “interconnected,” so crossing a critical boundary could destabilize the Earth’s entire life system, Sakschewski said.

But there is also an opportunity here, because solving a problem – such as preventing the earth’s average temperature from rising by more than 1.5 degrees Celsius above pre-industrial levels – “can lead to significant benefits in a range of areas,” the report says.

© 2024 AFP