The global population is facing what scientists describe as enormous risks that threaten civilization and all life on Earth. A Nature study presents new measurements by a global team of more than 40 scientists who have defined safe and just boundaries for the Earth system. These boundaries cover biophysical processes essential for life. If these limits are breached, cascading instability could threaten human civilization, and alarmingly, several boundaries have already been surpassed.
The World Commission, a panel of researchers, has identified and quantified safe and just boundaries in areas such as climate, biodiversity, freshwater, and air, soil, and water quality. One co chair of the commission, Joeta Gupta, notes that most of these boundaries are already being exceeded due to human activity.
Human actions are altering water flows, driving excessive nitrogen and phosphorus into rivers through agricultural fertilizers, and shrinking wildlife habitats. These changes jeopardize environmental stability, disrupt ecosystems, and affect human well being.
The climate boundary described as safe and fair refers to a maximum warming of 1 degree Celsius above preindustrial levels. It has already reached 1.2 degrees, meaning tens of millions are already affected by heat, drought, and climate related impacts. The goal of keeping warming below 1.5 degrees remains the minimum to avert catastrophic outcomes.
Lead author Johan Rockström warns that in five analyzed domains climate, biosphere, freshwater, nutrients, and atmospheric pollutants many boundaries have been crossed at both global and local scales. Without lasting transformation over time, the risk of crossing critical thresholds rises, potentially triggering irreversible changes that threaten the well being of today and future generations.
Everything on the planet is interconnected
The study stresses that Earth’s systems operate as a single interconnected mechanism. Changes in one region can ripple across the globe. Wendy Broadgate, Executive Director of the Land Commission, explains that the Earth system comprises a network of biophysical processes that influence regions far apart and at different scales. Intervention in one part of the world can thus trigger major consequences elsewhere.
The safe boundaries are defined as conditions that provide a stable and resilient Earth. The reference point is the Holocene interglacial period, which serves as a benchmark for a healthy planet. The authors state that a stable Earth relies on feedback loops that keep disturbances in check and maintain balance.
Growing human exposure to climate change, declining biodiversity, water scarcity, the ecological harm caused by fertilizers, and pollution all illustrate the pressures that push these limits toward breach. The health impacts of pollution and shifting atmospheric conditions are among the clearest signals of this trajectory.
Researchers hope this work forms a foundation for science based goals that cities, businesses, and nations can adopt to address the global ecological crisis. No longer an abstract concept, these boundaries provide concrete targets for policy and action.
The five safe and just boundaries of the world system
Climate: The safe and fair bound is a maximum of 1.5 degrees Celsius of warming above preindustrial levels. While current warming sits near 1.2 degrees, the 1 degree threshold has already been exceeded, a sign that social legitimacy at large scales is at risk and urgent measures are needed.
Biosphere: The safe and equitable state requires substantial preserved natural ecosystems, typically 50 to 60 percent undisturbed nature globally. With human activity now dominating two thirds of the planet, this boundary has already been surpassed.
Freshwater: For surface waters, a monthly flow change of about 20 percent is considered acceptable. The real global figure stands around 34 percent, indicating substantial alteration. Groundwater also shows a critical imbalance with global refill rates lagging well behind demand.
Nutrients: Safe levels for nitrogen and phosphorus have been exceeded. Nitrogen input is currently about twice the safe limit, while phosphorus use also surpasses safe thresholds, signaling growing nutrient pollution and ecosystem stress.
Pollutant aerosols: The global safe limit for atmospheric aerosols is defined by an index that has not yet been breached, indicating current conditions remain within an acceptable range but still demand close monitoring.
Foundational work: Earth Commission project documentation and Nature reporting provide the basis for these conclusions. The aim is to establish science driven targets and encourage government, corporate, and urban adoption to confront the ecological crisis.