Wildfires in carbon-rich tropical peatlands hit 2000-year high

Wildfires in tropical peatlands have surged to levels not seen in at least two millennia, according to a new synthesis of evidence from across the tropics. The analysis points to a clear break from natural patterns of variability and underscores the growing role of human activity in transforming some of the planet’s most carbon-dense landscapes.

Why peatlands matter

Peatlands are vast natural vaults of ancient plant material, built up over thousands of years in waterlogged soils. Despite often looking like low-lying swamps, they store more carbon than all of the world’s forests combined. When peat dries and burns, that slow-built carbon bank is rapidly released to the atmosphere as greenhouse gases, with consequences that amplify global warming.

A window into the deep past: charcoal locked in peat

To trace how peatland fires behaved long before modern monitoring, researchers examined tiny charcoal fragments preserved in peat cores. These natural archives, collected from Central and South America, Africa, Southeast Asia, and Australasia, capture a fire history spanning over 2,000 years. The pattern that emerges is striking: for most of that time, fire activity tracked climate rhythms—especially the frequency and intensity of drought.

A long decline, then a dramatic 20th-century surge

For more than a millennium, tropical peatland fires generally trended downward as large-scale climate drivers shifted. That gradual decline ended abruptly in the 20th century. Fire activity rebounded and then spiked, departing from the long-term baseline in ways that natural variability alone struggles to explain.

The human fingerprint

The surge is not uniform. It is strongest in Southeast Asia and parts of Australasia, where peatlands have been extensively drained for plantations and agriculture, forests cleared, and land converted for infrastructure and settlement. Draining peat lowers the water table and turns once-soggy soils into flammable fuel, primed to ignite during dry spells and to smolder for weeks. Fire is also used as a low-cost tool for land clearing, further elevating risk.

By contrast, peatlands that remain relatively remote in South America and Africa show less pronounced increases over the last century. Yet the analysis cautions that these regions are not immune: as populations grow and agricultural frontiers expand, the conditions that drove the fire surge elsewhere could take hold, especially under intensifying drought linked to climate change.

Climate and fire: a dangerous feedback loop

Peatland fires are not just a consequence of a warming, drying climate—they also contribute to it. When peat burns, centuries of stored carbon are released in a matter of days to months. That pulse of emissions adds to atmospheric greenhouse gases, which in turn raise temperatures and can heighten drought risk. The result is a feedback loop that makes future fires more likely and more severe, particularly in landscapes already weakened by drainage and deforestation.

What needs to change

The evidence points to a clear priority: keep peatlands wet and intact. Practical steps include:

• Halting new drainage and phasing out existing drainage where feasible to restore high water tables.
• Protecting remaining peat swamp forests from conversion and fragmentation.
• Adopting land-use practices that avoid fire, especially during dry seasons and drought years.
• Restoring degraded peatlands by rewetting, replanting native vegetation, and blocking drainage canals.
• Supporting local livelihoods that depend on healthy peat ecosystems, aligning conservation with community needs.
• Coordinating action across agencies, landowners, and sectors to manage fire risk at landscape scale.

Why urgency matters

Peat accumulates millimeter by millimeter, taking centuries to rebuild what a single fire can destroy in days. The 20th-century spike in tropical peatland burning signals a system under acute pressure—one that can no longer be explained by climate alone. With further warming on the horizon, the window to stabilize these carbon stores is narrowing.

Reducing peatland fires is both an immediate climate opportunity and a necessity. Keeping water in the ground, forests on the landscape, and fire out of routine land management can deliver rapid benefits: lower emissions, reduced haze and health impacts, and greater resilience to drought. The record of the last 2,000 years makes the message plain—when peatlands are protected and wet, they rarely burn. When they are drained and disturbed, fire becomes inevitable.