As the world faces the threat of reaching 1.5°C of warming, a key question arises: how bad could it get? One answer may lie in the history buried beneath our feet.
Deep in the Earth, ancient rocks hold a vast archive of past life. For paleontologists, these rocks offer insights into how life on land fared during periods of rapid climate warming. Our new study shows that plants were severely affected by past climate crises, and forests took millions of years to recover.
Around 252 million years ago, the Earth experienced the end-Permian mass extinction. Over 80% of marine species vanished, marking one of the largest extinction events in Earth’s history. The main cause was likely the massive release of greenhouse gases from volcanic activity in the Siberian Traps, a region in Russia.
While plants did not face mass extinction, they suffered significant damage. Extreme heat, droughts, ozone depletion, wildfires, and toxic contamination all took a toll. However, little is known about how plants in cooler regions, such as higher latitudes, were impacted. During the Permian period, ecosystems thrived in polar regions, but the end-Permian event wiped out these ecosystems entirely.
Our study examined plant fossils from the Sydney region of Australia, which was near the South Pole for at least 8 million years after the end-Permian extinction. These well-preserved fossils offer a glimpse into the long recovery process of plant life far from the source of the catastrophe.
The fossils revealed that conifers, such as modern pines and cypresses, were among the first plants to return after the event. However, their recovery was not immediate or straightforward.
We found that even two million years after the end-Permian event, higher temperatures led to the collapse of conifer populations. These plants were replaced by hardier, shrubby species resembling modern clubmosses. While the exact temperatures in Sydney are unknown, this period of intense heat lasted around 700,000 years and made survival difficult for trees and larger plants.
When cooling conditions finally returned, unusual plants, which resembled ferns but had seeds like conifers, began to thrive. These plants quickly established more stable forests in Sydney, a recovery that took less than 100,000 years. Over time, these plants dominated the landscape, paving the way for the lush forests during the Mesozoic era, when dinosaurs roamed.
Although forests eventually recovered, the new ecosystems looked very different from those before the end-Permian event. The plants that made up the forests were entirely new species.
The term “recovery” can be misleading. While forests may eventually return, the species lost during the extinction are gone forever.
By studying how ancient plant ecosystems survived extreme climate shifts, researchers hope to gain valuable insights into how modern ecosystems might cope with today’s climate crisis. With this knowledge, policymakers can better understand the potential outcomes of climate change and take action to mitigate the worst effects.
Fossil records provide a long-term perspective on climate change, offering data that can guide current decisions. Ecosystems rely on a delicate balance, with plants playing a critical role as the backbone of food webs and climate regulation.
The fossil evidence is clear: disruption of ecosystems can have long-lasting consequences. Protecting today’s ecosystems is more important than ever.
