If our planet were a patient, it would undoubtedly be in the intensive care unit. This stark assessment comes from the new “Planet Health Check 2025” report, published by the esteemed Potsdam Institute for Climate Impact Research (PIK).
As Boris Sakschewski, a lead author of the report and an expert in Earth system analysis at PIK, explains, “Many parameters are currently outside the normal range, indicating a critical state, and patient Earth is in danger.” He likens the situation to a person suffering from multiple severe health issues simultaneously: “You could compare it to having high inflammation markers, high cholesterol, poor liver values, bad lung function – multiple things going wrong at once. Each one is dangerous on its own, but they can amplify each other.”
The concept of “planetary boundaries,” first established in 2009, serves as the framework for this health check. These boundaries define the environmental limits within which humanity can safely operate without pushing Earth’s life-support systems to a dangerous breaking point. In 2009, three of these critical boundaries had already been crossed; by 2015, that number rose to four; and in 2023, it was six. Now, according to the PIK, a staggering seven out of the nine planetary boundaries have been breached.
Biosphere: Code Red
The biosphere encompasses all living organisms and the environments they inhabit, both on land and in water. Scientists gauge its health by examining its productivity and what remains after human activities. Alarmingly, this area fares even worse than climate change. The rate of species extinction and the destruction of natural ecosystems are far beyond the safe limits required for sustained survival, with no discernible signs of improvement.
Excess Nitrogen, Phosphorus Disrupt Biogeochemical Cycles
Over the last century, human activities – particularly intensive livestock farming, synthetic fertilizer use, and industrial and transport combustion – have doubled the amount of naturally available nitrogen. While nitrogen is essential for life, this extreme over-fertilization carries severe consequences. Excess nitrogen often seeps into groundwater, polluting rivers, lakes, and coastal marine zones. This leads to rampant algae growth, which in turn depletes oxygen, potentially killing all marine life in affected areas. On land, aggressive, fast-growing plants outcompete and displace species adapted to nutrient-poor conditions. Phosphorus compounds, also used as fertilizers, contribute to similar harmful effects. This overabundance of readily available nutrients diminishes biodiversity and destabilizes entire ecosystems, marking this planetary health indicator as “Code Red.”
Overload of New Substances: Unforeseen Long-Term Effects
Humanity currently produces and disperses nearly 350,000 artificial substances that interfere with natural processes and endanger ecosystems. To put this into perspective, organic life itself is predominantly composed of just six elements: hydrogen, carbon, nitrogen, oxygen, phosphorus, and sulfur. These human-introduced substances permeate every aspect of Earth’s systems, yielding unforeseen impacts. Microplastics have found their way into our drinking water, the insecticide DDT contaminates fish, and PFAS—dubbed “forever chemicals” due to their persistence and their impact on hormone systems in humans and animals—have been detected in sea foam along Germany’s North and Baltic Sea coasts. Sakschewski emphasizes the gravity of the situation: “Now we’re in a situation where thousands of substances are released into the environment untested, with new ones added every year. There’s an urgent need for action and international regulations.”
Climate Change: Earth’s Temperature is Rising
Earth’s climate is also in a critical state. Greenhouse gas concentrations have soared to unprecedented levels, far surpassing pre-industrial benchmarks. Of particular concern is the accelerating pace of global warming, reflected in the “radiative forcing”—a metric measuring the additional heat trapped in Earth’s atmosphere. Here, we’ve even entered the high-risk zone. This warming trend is primarily driven by human emissions of greenhouse gases, especially carbon dioxide (CO2).
Code Orange for Freshwater Resources
Human influence on water bodies and soil moisture is intensifying, largely due to agricultural irrigation, industrial consumption, domestic use, and human-induced climate change. This further destabilizes water systems, increasing the risk of both droughts and floods. Currently, over one-fifth of the world’s land surface experiences significant anomalies in dryness, water runoff, and soil moisture levels.
For Land Use
The pressure on Earth’s natural resilience is even more pronounced when it comes to land use. Human activities, including the expansion of croplands, pastures, logging, settlements, and infrastructure, heavily alter natural systems. Climate change, shifts in freshwater availability, and biosphere degradation all contribute to this challenge. Despite a slowed rate of deforestation, global forest cover continues to dwindle, now standing at just under 60%, significantly below the safe threshold of 75%. Should forest cover drop below 54%, we would enter the high-risk zone for this critical boundary.
In the Oceans
The world’s oceans play a vital role by absorbing over a quarter of the CO2 emitted by humans, thereby mitigating climate warming. However, this absorption leads to the formation of carbonic acid, which lowers the ocean’s natural pH and causes ocean acidification. The increasing acidity makes it progressively more difficult for corals and shellfish to form their essential calcium-based shells and skeletons. Sakschewski highlights the intricate interplay of planetary boundaries in the oceans: elevated ocean temperatures (a consequence of climate change) combined with inputs of nitrogen and phosphorus result in “dead zones” almost entirely devoid of oxygen. This devastates food webs and impacts the biosphere. Furthermore, many novel substances, such as plastics, inevitably find their way into the marine environment.
The Good News: Two Boundaries Remain in the Green Zone
Amidst the concerning data, there is some positive news: two planetary boundaries remain within the “green zone.” Air pollution continues to decline, and the ozone layer, which shields us from harmful cosmic radiation, is slowly but steadily recuperating. The recovery of the ozone layer stands as a powerful testament to the effectiveness of decisive collective action. Once the detrimental effects of chlorofluorocarbons (CFCs) on the ozone layer were understood, the global community united to ban their use through the Montreal Protocol. However, Sakschewski notes that this success involved a single substance for which an alternative was readily available. The challenges we face today are considerably more complex. Nevertheless, the intricate interconnections between planetary boundaries also present opportunities: improving one area can trigger positive ripple effects across others. “If you protect carbon sinks—like rainforests—you also protect soil moisture, freshwater systems, the climate, and the biosphere,” Sakschewski concludes. “It’s crucial to understand the causal network of the Earth system.”