New research into fossils from Earth’s most severe extinction event shows that the collapse of tropical forests was the key factor driving prolonged global warming.

Around 252 million years ago, the Permian–Triassic Mass Extinction, often called the “Great Dying,” wiped out a huge number of marine and land species.

This event has long been linked to intense volcanic activity in Siberia, which caused rapid global warming. But until now, scientists were unsure why extreme greenhouse conditions lasted for some five million years after.

A new international study led by the University of Leeds and China University of Geosciences reveals that the destruction of tropical forests severely reduced the planet’s ability to absorb carbon dioxide. This loss slowed recovery and caused high CO₂ levels to persist, maintaining a super-heated climate for millions of years.

Using detailed fossil analysis and ancient climate clues from rocks across China, researchers mapped how plant life collapsed during the extinction. The findings, published in Nature Communications, confirm that this collapse was a “tipping point” — a threshold that amplified warming by disrupting the natural carbon cycle.

Dr Zhen Xu, lead author from Leeds, said: “This event shows the only time in Earth’s history where tropical forests completely collapsed during extreme warming. Our data supports the idea that once such tipping points are crossed, climate change can accelerate beyond previous limits.”

Professor Benjamin Mills, who worked on climate simulations for the study, warned: “If today’s tropical forests were to collapse due to rapid warming, we risk locking in high global temperatures — even if we stop all carbon emissions. The carbon cycle would be altered on a geological scale, making climate recovery slow and difficult.”

The study highlights the critical role of tropical forests in regulating Earth’s climate and serves as a stark warning about the possible consequences of continued global warming.

As Professor Hongfu Yin and Professor Jianxin Yu of China University of Geosciences emphasises, “Understanding past climate tipping points through new science is vital to protecting Earth’s future.”