New Critical Threshold for the Planet Exceeded

Seven of the nine so-called planetary boundaries have now been exceeded. The latest is ocean acidification, which, according to a new report, has passed the limit of what is safe for marine life. And life in the sea is already feeling the effects.

Ocean acidification occurs when the ocean continues to absorb carbon dioxide from the atmosphere. Since the beginning of the industrial revolution, the acidity of the ocean’s surface water has increased by 30-40 per cent and is now at a level that poses a threat to marine life and, by extension, life on land.

“The consequences may not be immediate, but the long-term and indirect effects of crossing this threshold are extremely serious,” says Albert Norström, associate professor at the Stockholm Resilience Centre, research director for the Earth Commission at Future Earth Stockholm, and one of the researchers who contributed to the report from the Potsdam Institute for Climate Impact Research.

Incredibly important

There are already signs that small sea snails and mussels have weaker shells due to acidification. They are an important food source for many species, so when they weaken, it affects entire food chains.”They are incredibly important. They are the basis of marine ecosystems, and if you lose that, you get huge knock-on effects.”

Animals that feed on small creatures will find it harder to survive, which will ultimately have consequences for the fishing industry and food production.

Ocean acidification also has an impact on the climate.

“The ocean is a fantastic carbon sink. It absorbs about a quarter of all carbon dioxide emissions, but this function depends on healthy marine ecosystems.”

“Acidification is mainly driven by fossil fuel emissions, and one of the main solutions to reverse this trend is to reduce them,” say the researchers behind the report.

“We must reduce fossil fuel emissions now, not in the future. Not in ten or fifteen years. That will be too late.”

“Then we must protect and restore ecosystems on land and at sea. And invest in and scale up circular and sustainable systems for food, water and other natural resources.”

No coincidence

The planetary boundaries are quantitative assessments of how much human impact the Earth can withstand. With seven of nine boundaries crossed, only two remain at safe levels – Ozone layer depletion and increased aerosol concentration in the atmosphere. Decades of international action show that this trend can be reversed.

“We don’t think it’s a coincidence. International measures such as the Montreal Protocol, which focuses on the ozone layer, and various regulations that have been introduced to improve air quality, have had an effect,” says Albert Norström.

“It shows that if there is a will, global politics can reverse negative trends. Failure is ultimately a choice, not a fate.”