Charcoal produced by wildfires could trap carbon for hundreds of years and help mitigate climate change, according to new research led by Tyndall Centre’s Dr. Matthew Jones.
The new research, published in Nature, found that charcoal created by fires known as pyrogenic carbon could effectively ‘lock away’ a considerable amount of carbon for years to come and compensate carbon emissions from fires.
“CO2 emitted during fires is normally sequestered again as vegetation regrows, and researchers generally consider wildfires to be carbon neutral events once full biomass recovery has occurred. However, in a fire where some of the vegetation is not consumed by burning, this is transformed to charcoal. This carbon-rich material can be stored in soils and oceans over very long time periods,” Dr. Matthew Jones said.
The research has combined field studies, satellite data, and modelling to better quantify the amount of carbon that is placed into storage by fires at a global scale.
The paper, which was co-authored by Dr Cristina Santin and Prof Stefan Doerr, from Swansea University, and Prof Guido van der Werf, of Vrije Universiteit Amsterdam, explained that this needs to be considered in global fire emission models.
“Our results show that, globally, the production of pyrogenic carbon is equivalent to 12 percent of CO2 emissions from fires and can be considered a significant buffer for landscape fire emissions,” Dr. Jones said.
As vegetation in burned areas regrows, it draws CO2 back out of the atmosphere through photosynthesis. This is part of the normal fire-recovery cycle, which can take less than a year in grasslands or decades in fire-adapted forests. In extreme cases, such as arctic or tropical peatlands, full recovery may not occur for centuries.
This recovery of vegetation is important because carbon that is not re-captured stays in the atmosphere and contributes to climate change.
“Climate warming is expected to increase the prevalence of wildfires in many regions, particularly in forests. This may lead to an overall increase in atmospheric CO2 emissions from wildfires, but also an increase in pyrogenic carbon storage. If vegetation is allowed to recover naturally then the emitted CO2 will be recaptured by regrowth in future decades, leaving behind an additional stock of pyrogenic carbon in soils, lakes and oceans,” Dr. Jones added.
In an average year, wildfires around the world burn an area equivalent to the size of India and emit more carbon dioxide to the atmosphere than global road, rail, shipping and air transport combined.
Deforestation fires are a particularly important contributor to climate change as these result in a long-term loss of carbon to the atmosphere.