It’s not just climate – we’ve already breached most of the Earth’s limits. A safer, fairer future means treading lightly
by BAI Xuemei, BUNN Stuart, HASAN Syezlin, LADE Steven J, STEWARD-KOSTER Ben
We’ve blown past the safe and just limit for vital Earth systems, from climate change to the biosphere and the use of fertilisers and freshwater. For humans to thrive means living in safe limits
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 fertilisers 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 minimise 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 modelling, literature reviews and expert judgement. 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.
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