People once believed the planet could always accommodate us. That the resilience of the Earth system meant nature would always provide. But we now know this is not necessarily the case. As big as the world is, our impact is bigger.
People once believed the planet could always accommodate us. That the resilience of the Earth system meant nature would always provide. But we now know this is not necessarily the case. As big as the world is, our impact is bigger.
In research released today, an international team of scientists from the Earth Commission, of which we were part, identified eight “safe” and “just” boundaries spanning five vital planetary systems: climate change, the biosphere, freshwater, nutrient use in fertilizers and air pollution. This is the first time an assessment of boundaries has quantified the harms to people from changes to the Earth system.
“Safe” means boundaries maintaining stability and resilience of our planetary systems on which we rely. “Just”, in this work, means boundaries which minimize significant harm to people. Together, they’re a health barometer for the planet.
Assessing our planet’s health is a big task. It took the expertise of 51 world-leading researchers from natural and social sciences. Our methods included modeling, literature reviews and expert judgment. We assessed factors such as tipping point risks, declines in Earth system functions, historical variability and effects on people.
Alarmingly, we found humanity has exceeded the safe and just limits for four of five systems. Aerosol pollution is the sole exception. Urgent action, based on the best available science, is now needed.
Our work builds on the influential concepts of planetary boundaries by finding ways to quantify what just systems look like alongside safety.
Importantly, the safe and just boundaries are defined at local to global spatial scales appropriate for assessing and managing planetary systems—as small as one square kilometer in the case of biodiversity. This is crucial because many natural functions act at local scales.
