Spikes in UK wildfire emissions driven by peatland fires in dry years
VIEW FULL RESOURCEA new study, with NetZeroPlus researcher Professor Richard Betts as co-author, has revealed that as our springs and summers get hotter and drier, the UK wildfire season is being stretched.
More fires, taking hold over more months of the year, are causing more carbon to be released into the atmosphere as carbon dioxide.
When this is matched by plant regrowth carbon is drawn down from the atmosphere again but in the case of peat fires, carbon can be lost forever.
The researchers – from the universities of Cambridge and Exeter and the Met Office – found that despite accounting for only a quarter of the total UK land area that burns each year, wildfires that were able to burn into peat have caused up to 90% of annual UK fire-driven carbon emissions since 2001 – where these spikes in emissions occurred in particularly dry years.
Unlike heather moorland which takes up to 20 years to regrow after a fire, burnt peat can take centuries to reaccumulate. The loss of this valuable carbon store makes any increase in wildfire frequency on peatlands in the future a real cause for concern.
The findings have been published in the journal Environmental Research Letters.
Image Credit: A fire on UK moorland. Credit Sarah Baker
Co-author and NetZeroPlus Researcher Professor Richard Betts, of the University of Exeter and the Met Office, said:
“Climate change threatens UK peatlands through escalating fire risk, and the resulting emissions would add to the problem and make it harder to limit global warming to low levels. This underscores the urgency of both cutting emissions from fossil fuel burning and taking action to make peatlands more resilient.”
The Abstract
Wildfires on peatlands can nearly double global fire-driven carbon emissions, requiring centuries to re-sequester carbon (C) losses. Peatland fires require sufficiently hot, dry conditions and/or drainage for the peat to burn. Although these conditions have historically been infrequent, the warming and drying climate could increase the potential for wildfires and subsequent emissions. Here, we evaluate how climate change impacts peatland fire emissions by using the United Kingdom as a case study—where peatlands store an estimated 3.2 PgC. We use a fire emission model to quantify fire-driven C emissions using high-resolution land-surface data and fire-weather indices. Between 2001 and 2021, we estimate 0.8 TgC has been emitted from fires on peatlands, which can contribute up to 90% of total annual UK fire-driven C emissions. Consequently, protecting peatlands from fires in the UK would be a cost-effective way to slow climate change by avoiding future emissions. Peatland emissions spike during prominent dry years, implicating the inter-annual climate as a dominant driver of year-to-year variability. Integrating future climate projections suggests that a 2 ◦C global warming level could increase fire-driven C emissions in peatlands by over 60% solely via increased burn depths. Our findings are likely a bellwether for other temperate peatlands where climate change is leading to drier conditions, which increase burn depths and C emissions.