Grass half full? Adapting the hydrological management of grazed lowland peatlands to balance climate change mitigation with agriculture

Over 10% of the UK's land surface is covered by peat, representing the country's largest carbon store. Much of this land has now been modified by drainage to support grazing, crop cultivation and forestry, as a result of which peatlands are believed to emit over 18 Mt CO2 equivalent per year, around 4% of all the UK's greenhouse gas (GHG) emissions. Over half of these emissions derive from the relatively small area of lowland peat, the majority of which has been converted to arable and grassland agriculture. These areas are now among the most intense sources of GHG emissions from the land sector. Following the UK Government's commitment to Net Zero GHG emissions by 2050, there is an urgent need to reduce these emissions, and where possible to reinstate the natural function of peatlands as carbon sinks. However, drained lowland peatlands also support some of the UK's highest value farmland, and restoring these areas fully to wetland could have severe impacts on UK food security and the rural economy, as well as potentially 'offshoring' our emissions to other countries from which we import food. Recognition of this challenge led to the formation of the Defra Lowland Agricultural Peat Task Force, which will publish its report in October 2022. The report is expected to make detailed recommendations on the future management of peatland areas under cropland, such as those of East Anglia, which have been extensively researched by UKCEH and others. In comparison, areas of peat under grassland management, such as those of the Somerset Levels and Moors, are recognised to be a significant evidence gap, despite the fact that they typically retain far deeper peat and larger carbon stocks than the cropped Fenland peats. This PhD will seek to address this evidence gap.