Drivers of greenhouse gas emissions during recovery from fire in peatlands undergoing restoration (FIRE_RECOVER)

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European peatlands have historically formed in cool and wet conditions. The organic matter that is built up by plants every year is not degraded completely, and this means that, over time, the partly degraded organic matter has accumulated as peat with huge quantities of carbon locked away. In their natural state, peatlands areas continue to lock away carbon. We call such areas 'carbon sinks' and through this process, peatlands moderate the Earth's climate. However, around the world, peatlands have been impacted by human activities such as drainage, use as cropland or production forests, burning, and over-grazing. In most of these cases, the rate at which the plants build organic matter and the rate at which it is degraded changes such areas to switch from being a net carbon sink to a net source. In the UK and across Europe, as much as 80% of former peatlands have been damaged in some way. Such areas no longer look like peatlands, but the peat underneath the current land use still behaves differently to other soil types.Greenhouse gases (GHGs) such as carbon dioxide and methane released back to the atmosphere by disturbed peatlands amplify climate change in the same way as burning fossil fuels. Drainage and land use conversion can also alter the flow of water within and from these soils. It is only in hindsight that we have started to recognise how important it is to manage peatlands sustainably. Over the last decade or so, peatland restoration has been used as a tool to reduce greenhouse gas emissions from damaged peatlands, with >£20 mi spent in the UK alone.Unfortunately, the current projected impacts of climate change include more frequent drought spells and, alongside this, an increased risk of wildfire. A major wildfire occurred in May 2019 that affected >60 km2 of peatland in the Flow Country in the far north of Scotland. This fire was extinguished within 50 m of an existing research station that has been monitoring greenhouse gas emissions on an area where restoration activities had recently occurred. The proximity of the fire damage offers us the opportunity to compare the greenhouse gas emissions of carbon dioxide and methane on burned and unburned areas that have otherwise had identical histories of land management and are on similar slopes, aspect and peat depths. The equipment we are using also monitors a range of weather variables such as the amount of sunlight and rainfall, as well as how much of that sunlight ends up heating the soil or how rainfall and evapotransporation losses affect the water table. Therefore, by monitoring what happens to greenhouse gas emissions in burned relative to unburned sites, we will be able to measure whether burning has lasting impacts on greenhouse gas emissions (lowering the mitigation potential such sites have to offer) and whether they are more or less resilient to further fires. We therefore expect that this type of information will be of major benefit to those with an interest in the greenhouse gas mitigation potential of peatland restoration as a policy tool, or as a carbon offsetting mechanism. We also expect that the outputs created by this project will be of interest to the community interested in impacts of climate change and wildfire risk.