If our planet were a patient in a hospital, it would most likely be in intensive care. This sobering assessment comes from the new “Planet Health Check 2025” report, published by the esteemed Potsdam Institute for Climate Impact Research (PIK).
“Currently, many vital signs are outside the normal range, indicating poor health, and our patient, Earth, is in grave danger,” explains Boris Sakschewski, a lead author of the report and an expert in Earth system analysis at PIK. He likens the situation to a human body suffering from multiple ailments simultaneously: “Imagine high inflammation markers, elevated cholesterol, compromised liver function, and struggling lungs – all at once. Each issue is perilous on its own, but their combined effect is profoundly more dangerous.”
The foundation for this global health assessment was laid in 2009 with the development of “planetary boundaries” – a framework outlining the environmental limits humanity must respect to prevent irreversible damage to Earth’s life-support systems, which are fundamental for our own survival. Initially, three of these nine critical boundaries had been crossed. By 2015, that number rose to four, and a concerning six by 2023. The latest findings from PIK reveal an even more alarming reality: seven of the nine planetary boundaries are now severely breached.
The Biosphere: Sounding the Alarm with “Code Red”
The biosphere encompasses every living organism and environment on Earth, from the deepest oceans to the highest mountains. Its health is assessed through two key metrics: its natural productivity and how much remains untouched after human activity. This crucial area is currently in a worse state than even the climate itself. We are witnessing species extinction and a loss of natural ecosystems far beyond safe limits required for planetary stability, with no immediate signs of recovery.
Nutrient Overload: Disrupting Essential Cycles with Excess Nitrogen and Phosphorus
Over the last century, human activities – primarily intensive agriculture, the widespread use of synthetic fertilizers, and industrial combustion – have effectively doubled the amount of available nitrogen in natural systems. While nitrogen is essential for life, this extreme over-fertilization carries severe negative consequences.
Plants often cannot absorb all the excess nitrogen, leading to it leaching into groundwater, flowing into rivers and lakes, and ultimately polluting coastal marine zones. This nutrient surge triggers massive algal blooms, which then consume oxygen as they decompose, creating vast “dead zones” where marine life cannot survive. On land, aggressive, fast-growing plant species thrive on the abundance of nutrients, outcompeting and displacing native species adapted to leaner conditions.
Similarly, an overuse of phosphorus compounds as fertilizers contributes to this destructive cycle. Such an overwhelming excess of readily available nutrients severely diminishes biodiversity and destabilizes entire ecosystems. For this critical planetary health indicator, the prognosis is stark: Code Red.
A Deluge of Novel Substances: Unforeseen Long-Term Dangers
Humanity currently produces and disperses approximately 350,000 distinct substances that actively alter natural processes and jeopardize entire habitats. To put this into perspective, most organic life, from microscopic bacteria to colossal blue whales, is fundamentally composed of just six elements: hydrogen, carbon, nitrogen, oxygen, phosphorus, and sulfur.
These countless human-made substances permeate every corner of Earth’s systems, leading to unpredictable and often detrimental effects. Microplastics are now routinely found in our drinking water, harmful insecticides like DDT persist in fish, and PFAS, dubbed “forever chemicals” known to disrupt human and animal hormone systems, have been detected even in sea foam along Germany’s North and Baltic Sea coasts.
Boris Sakschewski emphasizes the gravity of the situation: “Even a single new substance can trigger global repercussions. We are now confronting a scenario where thousands of substances are being released into the environment without adequate testing, with new ones introduced every year. Urgent action and robust international regulations are desperately needed to address this.”
Climate Change: Earth’s Temperature Continues Its Upward Trajectory
Our planet’s climate is unequivocally in a perilous state. Greenhouse gas concentrations have reached unprecedented levels, far surpassing any values recorded before the industrial era. The most alarming trend is the accelerating pace of global warming, evidenced by rising “radiative forcing”—a measure of the additional heat trapped in Earth’s atmosphere. This critical metric has now pushed us into a high-risk zone.
The primary driver of this global warming is the emission of greenhouse gases by human activities, with carbon dioxide (CO2) being the most significant contributor.
Freshwater Resources: A “Code Orange” Warning
Human interference with global water bodies and soil moisture is intensifying. This is largely fueled by extensive agricultural irrigation, industrial water demands, increasing domestic consumption, and the compounding effects of human-induced climate change. These pressures further destabilize delicate water systems, dramatically increasing the risk of widespread droughts and devastating floods. Presently, over one-fifth of the world’s land surface exhibits significant and concerning deviations in dryness levels, water runoff patterns, and soil moisture content.
Land Use: A Strained Resilience
The strain on Earth’s natural resilience is particularly evident in land use. Human activities profoundly reshape natural systems through the expansion of cropland and pastures, extensive logging, the proliferation of settlements, and infrastructure development. Climate change, shifts in freshwater availability, and ongoing biosphere degradation are all interconnected factors exacerbating this pressure.
While the rate of deforestation has seen a slight slowdown, the overall global forest cover continues its alarming decline. Currently, forests cover less than 60% of the Earth’s land, significantly below the established safe minimum of 75%. Should forest cover recede further, dropping below 54%, we will inevitably enter a critical high-risk zone for this vital boundary.
Our Oceans Under Threat
The world’s oceans play a crucial role in mitigating climate change by absorbing over a quarter of the CO2 humanity emits. However, this essential service comes at a heavy cost: the absorbed CO2 transforms into carbonic acid, leading to a significant drop in the ocean’s natural pH level—a process known as ocean acidification. The increasing acidity makes it increasingly difficult for marine organisms like corals and shellfish to form and maintain their calcium-based shells and skeletons, threatening entire ecosystems.
Sakschewski highlights how intricately these planetary boundaries are linked within the oceanic environment. Elevated ocean temperatures, directly driven by climate change, combine with excessive nitrogen and phosphorus runoff to create expansive “dead zones” almost entirely devoid of oxygen. This phenomenon severely disrupts marine food webs, profoundly impacting the biosphere. Furthermore, many of the novel substances introduced by humans, such as plastics, inevitably find their way into the oceans, adding another layer of complex threat.
A Glimmer of Hope: Two Boundaries Remain in the “Green Zone”
Amidst the grim outlook, there is some positive news. Scientists report that two of the planetary boundaries are still within their “green zone.” Global air pollution continues to decrease, and the ozone layer, vital for protecting us from harmful cosmic radiation, is showing slow but steady signs of recovery.
The success story of the ozone layer serves as a powerful testament to humanity’s ability to reverse negative environmental trends through decisive action. Once it became unequivocally clear that chlorofluorocarbons (CFCs) were destroying the ozone layer, the international community united to ban their use through the landmark Montreal Protocol.
However, Sakschewski cautions that the ozone layer situation involved a single, identifiable substance for which a readily available replacement was found. The environmental challenges we face today are far more complex and multifaceted. Nevertheless, the intricate interconnections between planetary boundaries also present opportunities: positive action in one area can create beneficial ripple effects across others.
“If we prioritize the protection of natural carbon sinks, such as rainforests, we simultaneously safeguard soil moisture, freshwater systems, the global climate, and the overall biosphere,” Sakschewski emphasizes. “It is imperative that we understand and act upon the interconnected causal network that defines our Earth system.”