The most efficient carbon (C) store in the terrestrial biosphere are our peatlands – UK peatlands store more carbon than the forests of UK and France combined, and furthermore, unlike forests, peatlands can be perpetual greenhouse gas (GHG) sinks. Analysis for the UK’s National Emissions Inventory indicates that the UK’s peatlands currently emit at least 23 Mt CO2eq /yr (4% of reported UK GHG emissions for 2018), but if properly managed they could be a net sink of 2 Mt CO2eq /yr. Thus there is already an opportunity to manage peatlands to provide both an avoided loss of GHG and a perpetual sink. But are these National Emissions Inventory values the best we can do for peatlands?
The current approaches to bringing peatlands back to being GHG sinks has focused on raising water tables and revegetating with peat-forming species (eg. sphagnum mosses) but could that be improved and increased? There are approx. 18000 km2 of deep peat in the UK with up to 7000 km2 of that peat is under burn management of heather (Calluna vulgaris) and the total area of heather in the UK is nearer 30000 km2. Two GHG management opportunities arise from the occurrence of heather and its rotational burn management. Firstly, this supervisor has estimated that current burn management in the UK releases 821 PJ/yr (26 GW) which is more than the current UK biomass energy target – could that heather be harvested for biomass energy? Second, if heather biomass could not be burnt for energy could it go for local biochar production and re-applied to peatland, i.e. adding to carbon sequestration? This project will address these two possibilities, and specifically, address the following questions:
• What is the impact of cutting, rather than burning heather on peatland functions and services (e.g. GHG regulation, biomass, water quality) ?
• Can biochar enhance peatland function without affecting other ecosystem services?
• How much biochar can be applied to peat without detrimental impact?
• How much heather can be harvested from the UK?
The project will address these questions using a combination of field experiments and modelling studies based upon sites in the Peak District and the North Pennines. The output from the project is to provide novel choices for the sustainable management of UK upland peatlands in light of the government’s commitment to achieving net zero GHG emissions by 2050.