E+E Leader Team
There is something quietly alarming about looking 2,000 years into the past to understand what is happening right now. That is exactly what a new study published in Global Change Biology did — and what it found should give environmental professionals pause.
Researchers compiled charcoal records from 58 tropical peatland sites across four major ecoregions: the Neotropics, Afrotropics, Indomalaya, and Australasia. What they pieced together was a fire history stretching back two millennia — and a clear signal that what happened in the 20th century stands apart from everything before it.
For most of those 2,000 years, tropical peatland burning followed a recognizable pattern. Burning was relatively elevated in the early centuries, declined through the Little Ice Age, and then largely stabilized. Climate — specifically drought length and severity — was the primary driver. That part of the story is not surprising.
What is surprising is how sharply things changed after 1900.
A Shift That Climate Alone Cannot Explain
In the Indomalayan and Australasian regions — Southeast Asia and northern Australia — peatland burning in the 20th century reached levels that had no precedent in the entire 2,000-year record. The researchers found that while climate variables continued to influence fire risk, regional human activity became the dominant explanation for where burning spiked most severely.
In Southeast Asia, the culprit is fairly well-documented: drainage for oil palm, pulp plantations, and agriculture has dried out peatlands that were naturally resistant to fire. Once the water table drops, dry peat becomes fuel. Smoldering peat fires can burn for weeks or months, releasing large amounts of CO₂ and fine particulate matter with documented public health consequences.
The Neotropical and Afrotropical regions told a different story — burning actually declined or held steady in the 20th century, largely because those peatlands remain less accessible and less disturbed. But the researchers are careful not to treat that as reassurance. Commercial pressure on the Congo Basin and Amazonian peatlands is growing, and the study notes that future burning in those regions could follow the same trajectory as Southeast Asia.
What the Research Adds
This is the first compilation of tropical peatland fire history at this scale. Prior compilations focused on mid- to high-latitude peatlands. Bringing the tropics into that picture matters because tropical peatlands hold enormous carbon stocks — stocks that, when burned, contribute meaningfully to global emissions.
The study also found that hardwood swamps showed the sharpest recent increase in burning, reaching levels the researchers describe as unprecedented even relative to similar ecosystems under comparable climates.
The Underlying Point
Peatlands are naturally fire-resistant. Their high water tables are a built-in buffer. The fact that burning is now breaking historical records in disturbed regions is not a function of climate alone — it reflects what happens when land use decisions remove that buffer faster than ecosystems can adapt.
Conservation, rewetting, and sustainable land management are the interventions the researchers identify as most actionable. None of them are simple at scale. But the science now gives practitioners a much clearer baseline for understanding how far current conditions have already deviated from the norm.