A new study finds a sudden and unusual increase in wildfires in tropical peatlands during the 20th century, marking a clear departure from long-term historical patterns.
Peatlands are huge underground carbon reservoirs, storing more carbon than all the world’s forests combined. When these areas burn, large amounts of stored carbon are released into the atmosphere.
Wildfires have increased across the tropics in recent decades, but scientists have limited insight into how tropical peatland fires behave over time.
Ancient charcoal records reveal fire history
To better understand past fire activity, researchers examined charcoal preserved in peat deposits in Central and South America, Africa, Southeast Asia, and Australia. These records have allowed us to reconstruct wildfire patterns dating back more than 2,000 years.
The findings show that peatland fires have historically been closely linked to climate conditions, particularly how long and severe droughts have been.
Long-term decline followed by modern surge
The study revealed that wildfire activity in tropical peatlands has actually been declining for more than 1,000 years. This decline occurred in conjunction with changes in global temperatures and other natural climate factors.
However, this long-term trend reversed in the 20th century when wildfire activity increased sharply. Differences between regions suggest that human influence is the main reason for this rapid increase.
Human activities cause peatland fires
The increase in fires was most pronounced in parts of Southeast Asia and Australia. In these areas, actions such as draining peatlands for agriculture, clearing forests, and converting land for development have made peat soils much more likely to catch fire.
In contrast, similar increases were not seen in more remote peatland regions of South America and Africa. Still, lead author Dr Yuwan Wang warned that these areas could face increased risk of wildfire as populations expand and agriculture and infrastructure become more widespread.
There is an urgent need to protect carbon-rich ecosystems
“There is an urgent need to protect these carbon-rich ecosystems to avoid large amounts of carbon emissions that will further accelerate global warming,” said Dr Wang from the University of Exeter.
“Reducing tropical peatland burning could be achieved by promoting peatland conservation, sustainable resource management and ecosystem restoration, but this requires collaboration between multiple groups and needs to be implemented at a sufficiently large scale.”
The study, titled “Unprecedented fires in tropical peatlands in the 20th century compared to the past 2000 years,” global change biology.
