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 surface water of the ocean has increased by 30-40 percent and is now at a level that poses a threat to life in the ocean and, in the long run, to life on land.
The consequences may not be direct, but the long-term and indirect effects of crossing this boundary 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 Research.
Incredibly important
Already, there are signs that small sea snails and mussels have gotten weaker shells due to acidification. They are an important food source for many species, so when they are weakened, it affects entire food chains.
They are incredibly important. They are the basis for the marine ecosystems and if you lose that, you get huge scale effects.
The animals that feed on the small animals will have a harder time surviving and, in the long run, it will have consequences for the fishing industry and food production.
Ocean acidification also has effects on the climate.
The ocean is a fantastic carbon sink. It absorbs about a quarter of all the carbon dioxide that is released, but that function is dependent on marine ecosystems that are doing well.
Acidification is driven mainly by fossil emissions and one of the main solutions to reverse the trend is to reduce them, say the researchers behind the report.
We must reduce fossil emissions now and not in the future. Not in ten, fifteen years. It's too late.
Then we must protect and restore ecosystems on land and at sea. And invest 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 tolerate. With seven out of nine boundaries exceeded, only two are still at safe levels – the depletion of the ozone layer and the increased concentration of aerosol in the atmosphere. Decades of international efforts show that the trend can be reversed.
We do not think it's a coincidence. International efforts such as the Montreal Protocol, which focuses on the ozone layer and various regulations that have been implemented to get cleaner air, have had an effect, says Albert Norström.
It shows that if there is a will, global politics can reverse negative trends. Failing is ultimately a choice and not a destiny.
Corrected: In an earlier version, the number of planetary boundaries was incorrect in the introduction.
Climate change.
Loss of biological diversity.
Chemical pollution.
Changed land use.
Freshwater changes.
Overfertilization with nitrogen and phosphorus.
Depletion of the ozone layer (not exceeded).
Ocean acidification.
Increased concentration of aerosol in the atmosphere (not exceeded).
