If Earth were a hospital patient, it would likely be lying in the intensive care unit, that’s the overall message from the new Planet Health Check 2025 report published by the Potsdam Institute for Climate Impact Research (PIK).“Right now, many parameters are outside the normal range, meaning they are classified as poor, and the patient Earth is in danger,” said Boris Sakschewski, responsible for Earth system analysis at PIK and one of the report’s lead authors.“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,” he added.Researchers developed the benchmark for the planetary health check in 2009. It revolves around the concept of planetary boundaries and outlines what humans need to do to avoid overburdening the planet.Researchers have identified nine boundaries, which, if exceeded, can put Earth’s life support systems at risk, and with them, the foundation for human survival. In 2009, three had been exceeded; by 2015, it was four; in 2023, six. According to PIK, seven of the nine planetary boundaries have been breached.
Biosphere: Code Red
The biosphere includes all layers of Earth inhabited by living organisms on land and in water. Scientists measure its health using two indicators: its productivity and what remains after human exploitation.This area looks even worse than climate. Species extinction and loss of natural ecosystems are far beyond the safe zone needed for survival, and currently, there are no signs of improvement.
Excess nitrogen , phosphorus disrupt biogeochemical cycles
Over the past hundred years, humanity has doubled the amount of available nitrogen in nature through intensive livestock farming, synthetic fertilisers and combustion in industry and transport.Nitrogen is vital for the growth and survival of all living organisms, but extreme over-fertilisation has had many adverse side effects. Often, plants can’t absorb all the nitrogen, which then seeps into groundwater, washes into rivers and lakes, and pollutes coastal marine zones.There, it promotes the growth of certain algae, leading to oxygen depletion and, in the worst case, the death of all life in those areas. On land, fast-growing plants overtake species adapted to nutrient-poor conditions.Phosphorus compounds are also used as fertilisers, but the consequences can also be harmful. An excess of readily available nutrients narrows biodiversity and destabilises entire ecosystems. This boundary is severely breached. For this planetary health indicator: Code Red.
Overload of new substances means unforeseen long-term effects
Humanity produces and spreads nearly 350,000 substances that alter natural processes and threaten entire habitats. For comparison, organic life, whether a blue whale or bacterium , is mostly made up of just six elements: hydrogen, carbon, nitrogen, oxygen, phosphorus, and sulfur.The human-added new substances infiltrate all parts of Earth’s system and have unexpected effects. Microplastics are found in drinking water, the insecticide DDT in fish, and PFAS, so-called “forever chemicals” that affect hormone systems in humans and animals, have been detected in sea foam along Germany’s North and Baltic Sea coasts.But even one additional substance can lead to global consequences, said Sakschewski.“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,” he added.
Climate change: Earth’s temperature is rising
Earth’s climate is also in the danger zone. Greenhouse gas concentrations have reached record levels, far above pre-industrial reference values. Most concerning is the acceleration of global warming, shown by the so-called radiative forcing — a measure of how much additional heat enters Earth’s atmosphere. Here, we’ve even crossed into the high-risk zone.Global warming is primarily due to human emissions of greenhouse gases, particularly carbon dioxide (CO2).
Code orange for freshwater resources
Human impact on water bodies and soil moisture is increasing mainly driven by agricultural irrigation, industrial water use, domestic consumption and also due to human-driven climate change.This further destabilises water systems and raises the risk of droughts and floods. On more than one-fifth of the world’s land surface, there are now significant deviations in dryness, water runoff and soil moisture.
For land use
The strain on Earth’s resilience is even more pronounced in land use. Humans heavily intervene in natural systems through cropland, pasture, logging, settlements, and infrastructure. Climate change, changes in freshwater availability, and biosphere degradation also play a role here.Although the rate of deforestation has slowed, the overall amount of forest worldwide continues to decline. Currently, global forest cover has dropped to just under 60%, well below the safe minimum of 75%. If forests shrink below 54%, we approach the high-risk zone here as well.
In the oceans
The world’s oceans absorb more than a quarter of the CO2 emitted by humans, preventing it from warming the climate. Instead, however, it turns into carbonic acid, lowering the natural pH level and causing ocean acidification. The more acidic the water, the harder it is for corals and shellfish to form their calcium-based shells and skeletons.The oceans illustrate how closely the different planetary boundaries interact, said Sakschewski. High ocean temperatures — driven by climate change — combined with nitrogen and phosphorus inputs lead to so-called dead zones with almost no oxygen. This disrupts food webs, for example, the biosphere. And many of the novel substances, such as plastic, also end up in the ocean.
The good news: two boundaries remain in the green zone
It’s not all bad news: scientists say that two of the planetary boundaries are still within the green zone. Air pollution is continuing to decline and the ozone layer, which protects us from harmful cosmic radiation, is slowly, but steadily recovering.The ozone layer is a prime example of how decisive action can reverse negative trends. Once it became clear that chlorofluorocarbons (CFCs) were depleting the ozone layer, the global community banned their use through the Montreal Protocol.However, that case involved just one substance, for which a quick replacement was found, said Sakschewski. The current threats are far more complex.Still, the tight interconnections between planetary boundaries also offer opportunities and improving one area can positively impact others.“If you protect carbon sinks — like rainforests — you also protect soil moisture, freshwater systems, the climate, and the biosphere. You have to understand the causal network of the Earth system,” added Sakschewski.
