UK wildfire season 'getting longer' according to Cambridge scientists
New research finds that hotter, drier conditions are increasing the length and severity of wildfires across the UK, with peatland fires driving most carbon emissions
A new study has found that rising temperatures and drier conditions are extending and intensifying the UK's wildfire season, with peatland fires responsible for a significant share of carbon emissions.
Researchers at the University of Cambridge revealed that wildfires are occurring over more months of the year and releasing increasing amounts of carbon dioxide into the atmosphere. Fires burning on peatland, which is rich in carbon, have been responsible for up to 90% of the UK's annual fire-driven carbon emissions since 2001, despite peatland fires accounting for just a quarter of the total burned land area.
“We found that peatland fires are responsible for a disproportionately large amount of the carbon emissions caused by UK wildfires, which we project will increase even more with climate change,” said Dr Adam Pellegrini from the University of Cambridge’s Department of Plant Sciences, senior author of the study.
The research found that in particularly dry years, such as 2018 and 2019, peatland wildfires released tens of thousands of tonnes of carbon into the atmosphere. The 2018 Saddleworth Moor fire emitted 24,000 tonnes of carbon, while the 2019 Flow Country fire in Scotland released 96,000 tonnes.
Peat only burns when it is hot and dry enough, and climate change is making these conditions more frequent. Once burnt, peat takes centuries to recover, meaning carbon loss from these fires is not quickly offset by new growth. In contrast, heather moorland, which also burns, can regrow in about 20 years.
Dr Sarah Baker, the study’s lead author, said: “We found that in dry years, peatland wildfires were able to burn into the peat and release significant quantities of carbon into the atmosphere. In particularly dry years, this contributed up to 90% of the total wildfire-driven carbon emissions from the UK.”
The study found that the UK’s wildfire season has lengthened significantly, particularly in Scotland, where almost half of all UK wildfires occur. Between 2011 and 2016, wildfires typically occurred over one to four months each year, but between 2017 and 2021, this period extended to between six and nine months.
Nine percent of the UK is covered by peatland, which in a healthy state removes over three million tonnes of carbon dioxide from the atmosphere annually. However, researchers estimate that wildfires on UK peatlands emitted 800,000 tonnes of carbon between 2001 and 2021. They project that these emissions could increase by at least 60% if global temperatures rise by 2°C.
The team used data from the UK Met Office and mapped wildfires across the UK over the past 20 years to assess the extent of burned areas, the involvement of peatland, and the amount of carbon released. The study also modelled how climate change could further alter wildfire patterns in the future.
Dr Pellegrini emphasised the importance of peatland conservation to mitigate emissions. “Peatland reaccumulates lost carbon so slowly as it recovers after a wildfire that this process is limited for climate change mitigation. We need to focus on preventing that peat from burning in the first place, by re-wetting peatlands.”
The research was funded by Wellcome, the Isaac Newton Trust and UKRI, and is published in the journal Environmental Research Letters.