Scientists have uncovered clear evidence that ancient wildfires once scorched a temperate rainforest near the South Pole during the Late Cretaceous, about 90 million years ago. The findings, published in Communications Earth & Environment, provide the southernmost record of fire on Earth and shed light on how early peatlands formed under warm, high‑CO₂ conditions.
Lightning, Not Volcanoes, Likely Ignited the Fires
Analysis of a sediment core from Antarctica revealed microscopic charcoal particles concentrated in the younger layers of the core. Because the nearest volcanic source at the time was at least 400 kilometers away, researchers conclude that lightning strikes were the most plausible ignition source for these fires.
Warm Antarctic Climate Supported Rainforests
During the Late Cretaceous, average annual temperatures near the South Pole reached roughly 53 °F (12 °C), warm enough to sustain a swampy rainforest despite four months of continuous winter darkness each year. The study builds on a 2020 Nature paper that first described this ancient Antarctic rainforest.
Evidence of Surface Fires and Early Peatland Formation
Microscopic charcoal indicates that the fires primarily consumed soft conifer wood at relatively low temperatures, suggesting surface fires rather than canopy‑wide blazes. Burned tree trunks appear to have produced amber as a protective seal, while abundant peat moss spores point to the creation of the earliest known raised bog of its kind. Co‑first author Dr. Salzmann explained, “Wildfires, which became increasingly frequent, clearly played a decisive role in keeping the vegetation open and enabling peat‑bog development.”
Implications for Modern Climate Change
The researchers argue that understanding how fire and peatland ecosystems interacted under warm, high‑CO₂ conditions can improve predictions of modern peatland responses to climate change. Today, peatlands worldwide face growing wildfire risk as temperatures rise and droughts become more common.
By linking ancient fire regimes to early peatland evolution, the study offers a long‑term perspective on how ecosystems may adapt—or be altered—by future climate shifts.
Original reporting: KTBS 3 (Shreveport) — read the source article.
