Greenhouse gas balance for peat bogs in Northern-Ireland: moving towards Tier 2 emission factors using distributed eddy covariance measurements

The UK Climate Change Committee (CCC) has set a target to increase the area of peatlands in good condition to 55% by 2050 through restoration and improved management. However, due to limited data, it remains uncertain how much greenhouse gas a restored peatland emits or sequesters over time, making these interventions difficult to assess.

Northern Ireland has a peat soil coverage of about 242,600 ha, representing approximately 18% of its land area. Around two-thirds consists of semi-natural peatlands, defined as areas that have experienced some human intervention (like grazing and drainage) while retaining natural peatland characteristics. The total greenhouse gas emission from peatlands in Northern Ireland were previously estimated at around 2,232 kt CO2e (Evans et al., 2017), representing 10% of Northern Ireland's total emission. However, some emissions were estimated using the IPCC’s emission factors (Wetlands Supplement, 2013), which may not represent the specific character of peatland in Northern Ireland.

To develop better estimates for Northern Ireland and reduce uncertainty, we measured CO₂ and CH₄ fluxes to create carbon and greenhouse gas budgets for four semi-natural peat bogs using the eddy covariance method between 2022 and 2024. These sites represent different degrees of human intervention, including a grazed blanket bog, two relatively natural raised bogs with some hydrological intervention, and a recently restored raised bog. Our results show that the IPCC Tier 1 emission factors tend to overestimate the emissions from peatlands in Northern Ireland. In fact, on average, these sites appear to function as net carbon and greenhouse gas  sinks, with the grazed blanket bog showing the highest uptake. Here, we present results from these sites, and a discussion on the temporal and spatial dynamics of peatland carbon fluxes.