Wyoming fossils reveal ancient forests collapsed after extreme global warming

Fossils from Wyoming are revealing how forests responded when Earth experienced one of its most intense episodes of global warming around 56 million years ago. A new study, published in the journal Science on August 13, 2026, reconstructs the structure of forests during the Paleocene-Eocene Thermal Maximum, or PETM, and finds that their canopies became dramatically more open as temperatures rose and moisture became less available. The researchers estimate that forest canopy cover declined by about 60% and remained substantially reduced for more than 100,000 years before recovering. The finding offers a striking example of how climate-driven stress can alter entire ecosystems for extraordinarily long periods. Scientists caution that the PETM is not an exact preview of modern climate change, but its fossil record provides an important warning about what can happen when warming pushes vegetation beyond its environmental limits.Wyoming fossils reveal what happened to ancient forests during global warmingThe new research is titled “Forest canopy decline under elevated CO2 during the Paleocene-Eocene Thermal Maximum” and was published in Science by Regan E. Dunn and colleagues. The team ...