German institute warns that only two limits compatible with stable and sustainable ecosystems were not violated. It is a risk to life on the Blue Planet.
If Earth were a patient, she would probably be admitted to an intensive care unit. This is a sad reality, but the latest Planet Health Check report brings new, worrying data about the health of our planet.
“Right now, many parameters are outside the normal range, classified as bad, which means that the Earth is in danger“, said Boris Sakschewski, responsible for the scientific assessment of the state of the planet, published annually by the Potsdam Climate Impact Research Institute (PIK).
“We could compare this to having elevated inflammatory markers, high cholesterol, bad liver values, poor lung function — several things going wrong at the same time. Each of them is dangerous in its own right, but they can amplify each other”, added the author.
Researchers developed the benchmarks for the Planetary Health Check in 2009. They revolve around the concept of planetary boundaries and describe what humans need to do to avoid overwhelming the planet.
The researchers identified nine limits that, if exceeded, could endanger Earth’s life support systems and, with them, the basis for human survival. In 2009, three of these limits had been exceeded; in 2015, four; in 2023, six. According to PIK, by 2025, seven of the nine planetary boundaries have been breached.
Biosphere: red alert
The biosphere comprises all layers of the Earth inhabited by living organisms, on land and in water. Scientists assess their health based on two indicators: productivity and ability to recover after human exploitation.
This aspect of the planet’s health is in a even worse than the weather itself. The extinction of species and the loss of natural ecosystems are far beyond the safe zone necessary for survival, with no sign of improvement.
Excess nitrogen and phosphorus
In the last 100 years, humanity has doubled the amount of nitrogen available in nature through intensive livestock farming, synthetic fertilizers and combustion in industry and transport.
Nitrogen is vital for the growth and survival of all living organisms, but excessive fertilization causes adverse side effects. Plants often cannot absorb all the nitrogen, which infiltrates groundwater, is transported to rivers and lakes, and pollutes marine coastal areas.
The substance promotes a consequent oxygen deficiency, which can cost the lives of the species that inhabit these areas. In soils with too much nitrogen, fast-growing plants supplant species adapted to living with fewer nutrients.
Phosphorus compounds, also used as fertilizers, present the same risk. An excess of available nutrients reduces biodiversity and destabilizes entire ecosystems. This limit is seriously exceeded, according to the PIK report.
Unpredictable effects of new substances
Humanity produces and disperses around 350,000 substances that alter natural processes and threaten entire habitats. For comparison, organic life — whether a blue whale or bacteria — is primarily composed of just six elements: hydrogen, carbon, nitrogen, oxygen, phosphorus and sulfur.
New substances introduced by humans infiltrate all parts of the Earth system and have unpredictable effects. Microplastics are found in drinking water; DDT in fish; and so-called “forever chemicals” (PFAS), which affect the hormonal systems of humans and animals, have already been detected in the umbilical cord of babies.
A single new substance can have global consequencessaid Sakschewski.
“We are now in a situation where thousands of substances are released into the environment without being tested, with new substances being added every year. There is an urgent need for international action and regulation,” he added.
Global warming
Earth’s climate is also in danger. Greenhouse gas concentrations have reached record levelsfar above pre-industrial reference values. The most worrying thing is the acceleration of global warming, demonstrated by the so-called radiative forcing — a measure of the amount of additional heat entering the Earth’s atmosphere. In this criterion, we have already crossed the line into the high-risk zone.
Global warming is mainly due to human emissions of greenhouse gases, especially carbon dioxide (CO₂).
Orange alert for freshwater resources
The human impact on water bodies and soil moisture is increasing, driven mainly by agricultural irrigation, industrial water use, domestic consumption and also human-caused climate change.
This further destabilizes water systems and increases the risk of droughts and floods. Across more than a fifth of the planet’s land surface, there are now significant deviations in patterns of drought, water runoff and soil moisture.
I use C only
The pressure on the planet’s resilience is even more visible in land use. Human beings strongly interfere with natural systems through agriculture, pastures, logging, settlements and infrastructure. Climate change, changes in freshwater availability and biosphere degradation also play an important role in this regard.
Although the rate of deforestation has decreased, the total amount of forests in the world continues to decline. Currently, global forest coverage has fallen to just under 60% — well below the safe minimum of 75%. If forests fall below 54%, we will also move closer to the high-risk zone.
Ocean acidification
The world’s oceans absorb more than a quarter of the CO₂ emitted by humans. But, along with this essential contribution to mitigating global warming, ocean acidification occurs — the gas turns into carbonic acid, reducing the natural pH level of the water. The more acidic the seas are, the harder it is for corals and shellfish to form their calcium-based shells and skeletons.
“The oceans illustrate how different planetary boundaries are intimately interconnected,” says Sakschewski. High ocean temperatures — driven by climate change — combined with the input of nitrogen and phosphorus, lead to the formation of so-called dead zones, almost devoid of oxygen. This disrupts food chains. Not to mention new substances, such as plastic, also present in the ocean.
The two borders still in the green zone
Scientists claim that two of the planetary boundaries still remain in the green zone.
Air pollution continues to decline, and the ozone layer — which protects against harmful cosmic radiation — is slowly but steadily recovering.
The ozone layer is an excellent example of how concrete actions can reverse negative trends. When it became clear that chlorofluorocarbons (CFCs) were destroying the ozone layer, the international community banned their use through the Montreal Protocol.
“This case, however, only involved one substance, for which a substitute was quickly found. Today’s threats are much more complex,” explains Sakschewski.
Still, the close interconnections across planetary boundaries also offer opportunities: improving one area can have positive impacts on others.
“If we protect carbon sinks — like tropical forests — we also protect soil moisture, freshwater systems, the climate and the biosphere. We need to understand the causal network of the Earth system,” concluded Sakschewski.
