Oceans of Acid – Passing Another Planetary Tipping Point

Earlier this year, it became clear (at least to us non-scientists) that the world was close to passing a seventh critical planetary boundary and tipping point.  Now, research has determined the boundary of ocean acidification has been crossed.

Oceans, which cover 71% of the Earth’s surface, have increased by 30-40% increase in acidity since the start of the industrial era, pushing marine ecosystems beyond safe limits. This weakens the ocean’s role as Earth’s stabilizing force.

Planetary boundaries are the thresholds that keep life on Earth within a safe operating zone or safe boundaries.  Essentially, they are what keep Earth habitable for most species, including humans.

Poor Report on Planetary Health

Last month, the Potsdam Institute for Climate Impact Research released its findings - The Planetary Health Check 2025 – where they have determined ocean acidity had crossed a critical threshold for marine life. The authors state the obvious - human activities have pushed Earth beyond its ‘Safe Operating Space.’

Heat records are being broken all over the world, and the oceans are bearing the brunt of our modern civilization, as carbon emissions continue to rise. Greenhouse gas concentrations have reached record levels, global warming appears to be accelerating, and conditions are continuing to worsen.

A Safe Operating Space, as defined by the report, “Refers to the range of environmental conditions in which humanity can safely live, grow, and prosper long-term. Staying within this space ensures Earth’s systems remain stable and supportive of life. Going outside it is very different from anything humans have experienced in approximately the last 12,000 years, a stable period called the Holocene Epoch.”

Albert Norström, co-author of the report, said “This intensifying acidification stems primarily from fossil fuel emissions, and together with ocean warming and deoxygenation affects everything from coastal fisheries to the open ocean. The consequences ripple outward impacting biodiversity, food security, global climate stability, and human wellbeing.”

Stressed Coral Reefs

Coral reefs provide habitat to 25% of the world’s marine species and contain some of the most diverse and valuable ecosystems on Earth. They are considered one of the most vulnerable systems to global heating.  The rising acidity of the oceans threatens coral reefs by making it harder for corals to build their skeletons.

The Global Tipping Points report, published by the University of Exeter, revealed that since January 2023, coral reefs have been experiencing the fourth—and most severe—global bleaching event on record, with over 80% of reefs across more than 80 countries affected by extreme ocean temperatures.

Per Professor Tim Lenton, an author of the report at the University of Exeter’s Global Systems Institute, “The first tipping of widespread dieback of warm water coral reefs is already under way.”

Breached Boundaries

The outlook is indeed precarious. If you are curious, the other six breached boundaries are as follows:

• climate change

• biosphere integrity

• land system change

• freshwater use

• biogeochemical flows

• novel entities

  
  

All the above planetary boundaries have showed a worsening trend. Only two - ozone depletion and aerosol loading - remain in the ‘safe zone.’

UN data shows that levels of carbon dioxide in the atmosphere soared by a record amount in 2024 to hit another high.  Not good news, as the U.S., the world’s second largest emitter in carbon emissions, has an administration denying climate change and taking the country backwards on clean energy. The upcoming UN Climate Change Conference in Brazil also doesn’t hold much promise, for the moment at least. 

The world will be watching, but will it act in time to reverse the breaching of critical planetary boundaries?