Greenland ice sheet
Written by Olivia Nater | Published: October 10, 2025
A worrying new report reveals that humanity has breached the seventh of nine critical planetary boundaries, with severe consequences for Earth’s life support system.
The newly breached planetary boundary is ocean acidification, caused by excess carbon dioxide from fossil fuel emissions. The other six boundaries that had already been breached are climate change, biosphere integrity (biodiversity loss), land system change (particularly deforestation), freshwater use, biogeochemical flows (including agricultural pollution), and novel entities (such as synthetic chemicals and plastics). All seven breached boundaries show worsening trends. The only two boundaries that remain in the safe zone are ozone depletion and aerosol loading (air pollution).
The Planetary Boundaries Framework identifies nine processes that have been scientifically proven to play a key role in regulating the stability, resilience, and life‑sustaining functions of the Earth’s systems. For each of the nine planetary boundary processes, the framework identifies a “safe operating space,” in which the conditions on Earth will remain reliable and hospitable for generations to come. When available evidence indicates that we have left this safe operating space for a boundary, it is considered breached.
The new report, the 2025 Planetary Health Check, written by a global team of scientists and published by the Potsdam Institute for Climate Impact Research (PIK), finds that overall, our planet is now in the upper end of the “danger zone,” pushing closer to the “high risk zone,” where the risk of triggering catastrophic tipping points, such as the collapse of major ice sheets and the disappearance of the Amazon rainforest, is very high.
The report warns that while the window for returning to a safe operating space remains open, it is closing fast.
Following the last ice age, for more than 10,000 years, humanity enjoyed a period of climatic stability and resilient ecosystems. This epoch is called the Holocene, and it enabled the rise of agriculture, urbanization, and complex civilizations. In the mid-20th century, however, things began to change rapidly. This period is called “The Great Acceleration,” and is characterized by exponential population growth and increase in socio-economic activity, and resulting environmental degradation. The Great Acceleration marked the beginning of our current epoch, the Anthropocene, in which human activity is the dominant force shaping planetary systems.
As damaging human activities continue to expand, driven by continued population growth and economic development, we are pushing Earth’s systems dangerously close to breaking point. Let’s look at three of the breached boundaries in more detail.
Two variables define the climate change boundary: atmospheric CO₂, and anthropogenic radiative forcing, the heating effect caused by greenhouse gases in the atmosphere. When the report was written, atmospheric CO₂ was at 423 ppm, far above the planetary boundary of 350 ppm. Global CO₂ levels are still increasing (standing at 424.69 ppm on October 8, 2025). Total anthropogenic radiative forcing is now +2.97 W/m², around twice the planetary boundary threshold of +1.5 W/m². The report warns that mounting evidence shows that the Earth’s carbon storage capacity is weakening:
“Natural carbon sinks on land are saturating or turning into carbon sources, global warming appears to be accelerating, and early warning signs of tipping behavior are emerging in key systems.”
The majority of carbon dioxide emissions are absorbed by the ocean, which helps us from a climate change point of view, but all that CO₂ is making seawater more acidic, which results in severe damage to marine organism. Corals and shellfish use a form of calcium carbonate called aragonite to build their shells and skeletons. The aragonite saturation state (Ω) reflects the availability of carbonate in seawater relative to the amount needed for stable aragonite formation, with values below 1 indicating corrosive conditions. The new report reveals that the global mean surface aragonite saturation state is now 2.84, just below the planetary boundary of 2.86 (the lower the value, the worse the boundary transgression).
Biodiversity is suffering too, with an extinction rate above 100 extinctions per million species-years (E/MSY), meaning more than 100 out of one million species go extinct every year, far exceeding the planetary boundary of 10 E/MSY. The other variable for biosphere integrity is human appropriation of net primary production (HANPP), which measures the extent to which human activities, such as agriculture, forestry, and urbanization, inhibit net primary production (the biomass produced by plants) and withdraw energy by harvesting products for human use and consumption. HANPP in 2025 sits at 30%, which is three times the 10% planetary boundary and in breach of the 20% “high-risk level.”
The authors note that the seriousness of rapid biodiversity loss is hard to overstate:
“The loss of vital services provided by ecosystems also has the potential to deprive our societies of irreplaceable sources of food and feed, energy, materials and medicines, while destabilizing the entire Earth system. Examples are the loss of pollinators, which are needed for more than 75% of food crop species, and the loss of CO₂ uptake sequestration capacity, which could significantly accelerate climate change.”
Indeed, a recurring theme throughout the report is the critical interlinkages between all planetary boundaries. No system operates in isolation, which means degradation of one system will also negatively affect the other ones. As shown for example in the excerpt above, loss of biodiversity affects climate change, and the inverse is also true. Countless species are being pushed closer to extinction due to the impacts of climate change, such as habitat deterioration, loss of prey, increased risk of invasive species, etc.
These interconnections mean that potential tipping points are also linked. For example, sustained current atmospheric CO₂ concentrations of 420 ppm would result in warming of 2.5-3°C, which would likely lead to the collapse of the Greenland ice sheet and of the subpolar ocean circulation gyre. The collapse of either system would in turn destabilize the Atlantic Meridional Overturning Circulation (AMOC), a major, vital ocean current which distributes heat between the northern and southern hemispheres. The collapse of the AMOC could push the Amazon rainforest over the edge due to weakened moisture transport into South America. A large-scale dieback of the Amazon rainforest system would result in unthinkable biodiversity loss, and lead to the release of massive amounts of stored carbon, accelerating global warming.
This is just one example of how triggering one tipping point could eventually lead to catastrophic changes across the whole planet, threatening humanity’s very existence. The fact that the breached boundaries are still seeing worsening trends is deeply alarming. It is high-time world leaders start acknowledging planetary boundaries and implementing meaningful measures to rein in the destructive human enterprise. A more sustainable path, including empowering population solutions and more sustainable economic systems, is within reach – what’s missing is the political will to implement it.
