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

欧洲的泥炭地历来是在凉爽潮湿的条件下形成的。植物每年积累的有机物质并没有完全降解，这意味着，随着时间的推移，部分降解的有机物质已经积累成泥炭，并锁定了大量的碳。在自然状态下，泥炭地地区继续锁住碳。我们把这些地区称为“碳汇”，通过这个过程，泥炭地缓和了地球的气候。然而，在世界各地，泥炭地受到了人类活动的影响，如排水、用作农田或生产林、焚烧和过度放牧。在大多数情况下，植物形成有机物质的速度和降解有机物质的速度会改变这些地区，使其从净碳汇转变为净来源。在英国和整个欧洲，多达80%的曾经的泥炭地以某种方式遭到了破坏。这些地区看起来不再像泥炭地，但当前土地利用下的泥炭仍然表现出与其他土壤类型不同的行为。受干扰的泥炭地向大气释放二氧化碳和甲烷等温室气体(GHGs)，以与燃烧化石燃料相同的方式放大气候变化。排水和土地利用转换也会改变这些土壤内部和外部的水流。只是在事后，我们才开始认识到可持续管理泥炭地的重要性。在过去十年左右的时间里，泥炭地恢复一直被用作减少受损泥炭地温室气体排放的工具，仅英国就有20英里。不幸的是，目前预测的气候变化影响包括更频繁的干旱，以及随之而来的野火风险增加。2019年5月发生了一场严重的野火，影响了苏格兰北部流动县60平方公里的泥炭地。这场大火被扑灭了，距离一个现有的研究站不到50米，该研究站一直在监测最近进行修复活动的地区的温室气体排放。火灾破坏的距离让我们有机会比较烧毁和未烧毁地区的二氧化碳和甲烷的温室气体排放量，这些地区本来有着相同的土地管理历史，而且位于相似的坡度、坡向和泥炭深度。我们使用的设备还监测一系列天气变量，如日照和降雨量，以及有多少阳光最终加热土壤，或者降雨和蒸发输送损失如何影响地下水位。因此，通过监测燃烧地点相对于未焚烧地点的温室气体排放发生了什么，我们将能够衡量燃烧是否对温室气体排放产生持久影响(降低了这些地点必须提供的缓解潜力)，以及它们对进一步火灾的弹性是否更强或更弱。因此，我们预计，这类信息将对那些对泥炭地恢复作为政策工具或碳抵消机制的温室气体缓解潜力感兴趣的人大有裨益。我们还预计，该项目产生的成果将引起对气候变化和野火风险的影响感兴趣的社区的兴趣。

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.