This 2017 report summarises project work undertaken on behalf of the then Department for Business, Energy and Industrial Strategy (BEIS) to develop and implement a new method for reporting greenhouse gas (GHG) emissions from peatlands in the UK’s emissions inventory. The work builds on the Intergovernmental Panel on Climate Change (IPCC) 2013 Wetlands Supplement, by providing empirically-based and UK-specific ‘Tier 2’ estimates of emissions from a representative range of peat land-use and condition categories.

It collates consistent spatial information on peat extent and condition from each of the four UK administrations, as well as the most peat-rich Crown Dependencies and Overseas Territories (Isle of Man and Falkland Islands respectively).

These data were used to assess the overall extent and condition of UK peatlands; to estimate change in condition over the period from 1990 to 2013; to implement the first UK-wide inventory of peatland GHG emissions over this period; and to project future peat-derived GHG emissions through to 2050 based on a set of five illustrative scenarios.

Key findings were:


• Based on updated figures obtained during this project, the UK’s peatlands are estimated to occupy a total area of around 3.0 million hectares (12.2 % of the total UK land area). Another 280,000 ha of peat are believed to be present in the Falkland Islands (around one quarter of the land area).


• Of the UK’s total peat area, approximately 640,000 ha (22%) is estimated to remain in a near-natural condition. This area of near natural bog and fen is believed to be continuing to act as a significant net sink for CO2, of approximately 1,800 kt CO2 yr-1. This CO2 sink is however counterbalanced by similar emissions of methane (CH4) when its greater 100-year Global Warming Potential is taken into account making near-natural peatlands close to carbon neutral. Over longer time-horizons, natural peatlands have a strong net cooling impact on climate, due to the longer atmospheric lifetime of CO2 compared to CH4. While near-natural bogs are very small net GHG sources, for near-natural fens, CO2 uptake exceeds CH4 emission on a CO2-equivalent basis making them a very small net GHG sink. However the areas that could be definitely mapped as near-natural fen from available data were small.

• A further 1,213,000 ha (41%) of the UK peat area remains under some form of semi-natural peatland vegetation, but has been affected to varying degrees by human activities including drainage, burn management, and livestock grazing.

This has led to drying of the peat, loss of peat-forming species and erosion, converting these areas into net GHG sources. Although the emissions per unit area of modified peatland are relatively low, their great extent makes them significant contributors to overall UK peatland GHG emissions (3,400 kt CO2e yr-1, 15% of total emissions).  


• Arable cropland occupies just 7% of the UK’s peat area, but has the highest GHG emissions per unit area of any land-use, with high rates of both CO2 and N2O emissions as a result of drainage and fertilisation. As a result, cropland is estimated to emit 7,600 kt CO2e yr-1, 32% of total UK peat GHG emissions. Around two thirds of the cropland area is on ‘wasted’ peat (shallow residual organic soils where much of the original peat has already been lost), predominantly in the Fenlands of East Anglia. The true extent and rate of GHG emission from wasted peatlands is not well quantified, making this component of the total cropland emission particularly uncertain.  


• Peatlands converted to Grassland occupy a further 8% of the UK’s peat area, and emit ~6,300 kt CO2e yr-1, 27% of total UK peat emissions. Drained intensive grasslands in lowland areas are the primary source of these emissions.  

• Around 16% of the UK peat area is covered by woodland, the majority of which is drained conifer plantation. The UK inventory currently applies a model-based (‘Tier 3’) approach to inventory reporting for forests, but data collated for this study were used to derive empirically-based ‘Tier 2’ emissions estimates for comparative purposes. Both the area estimates and emissions factors associated with afforested peatlands are uncertain, and the Tier 2 emission factors cannot take into account factors such as the age of forest, differences between tree species or forest management practices. However 1 the Tier 2 emission estimates suggest that peat under forestry in the UK could be emitting around 4,600 kt CO2e yr-1 (20% of the UK total). This figure does not take into account CO2 uptake into tree biomass, or the after-use of harvested timber.

• Industrial peat extraction for horticultural use occupies a comparatively small proportion of the UK’s peat area (4,600 ha). A much larger area (mainly in Northern Ireland and Scotland) has been affected by current or historic domestic peat cutting for fuel (145,000 ha), and the resulting modification of vegetation and hydrology is thought (in the absence of subsequent restoration) to have converted these areas into sustained GHG sources. The combined total GHG emission from extracted areas of ~1,200 kt CO2e yr-1 derives mainly from these domestic extraction areas, despite the higher emissions per unit area of industrial extraction sites.  

• In total, the UK’s peatlands are estimated to be emitting approximately 23,100 kt CO2e yr-1 of GHG emissions. This emission is sufficient to convert the UK LULUCF inventory as a whole from a net GHG sink into a net GHG source.

• There are large inter-regional variations in the main sources of peatland GHG emissions. In Scotland, with the largest total peat area, the largest sources are modified blanket bog and forests. In England, the smaller (and partly wasted) peat area makes a larger overall contribution to total UK emissions, as a result of intensive arable and grassland cultivation, predominantly in lowland areas. In Northern Ireland, intensive grassland in the lowlands and domestic peat extraction in the uplands are major sources, and in Wales sources include intensive and extensive grasslands and modified bogs. It was not yet possible to develop an inventory for the large area of peat in the Falkland Islands, but a significant proportion of this area is thought to be modified by grazing, erosion and fire.

• Since 1990, an estimated 95,000 ha of UK peatland have been subject to some form of active restoration intervention, of which around 70,000 ha has involved some form of re-wetting. These activities have occurred in all of the UK administrations, with the majority having taken place in areas of modified blanket bog. Some re-wetting and restoration to peatland vegetation has also occurred in areas of plantation forest, cropland, grassland and peat extraction. In total, these activities are estimated to have generated an emissions reduction since 1990 of 423 kt CO2e yr-1. It is likely that other unrecorded restoration activities, land-use changes and management activities (for example as part of agri-environment schemes) have had an additional influence on peatland emissions, but available data were insufficient to allow these changes to be reported.

• The emissions estimates obtained during this project represent a major (more than tenfold) increase in the total peat-derived emissions captured in the current UK inventory. This reflects a significant development in the IPCC methodology following publication of the 2013 Wetland Supplement, which allows for more complete reporting of peatland emissions than was previously possible. This new approach by IPCC has led to much more detailed reporting of peatland emissions in the LULUCF inventory, incorporating improved data on peat condition including the extent of peat mapped; peat condition classification and mapping; estimated emission factors; treatment of wasted peats; and methodology applied to forest on peat.

Structured diagram of peat land types

• Future emissions projections to 2050 based on a set of illustrative scenarios suggest that currently legislated peat restoration measures (mainly the phasing out of peat extraction in England) will have limited impact on emissions, but that current levels of ambition on peat restoration in all four countries could deliver over 4 Mt CO2e yr-1 of emissions reductions by 2050. A more ambitious restoration scenario, including removal of 50% of forest planted on peat since 1980, could deliver over 8 Mt CO2e yr-1 of emissions abatement. However none of our scenarios incorporated large-scale cessation of drainage-based agriculture on lowland peat, which (as it accounts for 60% of all current emissions) placed effective limits on the degree of emissions abatement that could be achieved. 2 In summary, although around 70% of UK peatlands retain some form of semi-natural vegetation cover, over three quarters are in a modified state, ranging from relatively minor changes to vegetation cover and hydrology, through to the complete replacement of wetland vegetation by arable and horticultural crops, agricultural grasses and non-native conifers, with accompanying deep drainage. As a result, UK peatlands have transitioned from modest historical net GHG sinks (an estimated pre-anthropogenic sink, based on 100 year Global Warming Potentials, in the region of 0.25 Mt CO2e yr-1) into large emission sources (exceeding 23 Mt CO2e yr-1).

The contrast between these two values highlights that the priority for peatland management should be to reduce current high emissions; it is unlikely that so-called ‘negative emissions’ from peat formation will be able to offset emissions from other sectors.   Widespread and ongoing peat restoration across the UK has contributed to a reduction in total emissions, but to date the majority of restoration has taken place within modified upland bogs, which produce modest emissions sources per unit area, rather than categories with higher Tier 2 emission factors per unit area such as cropland, lowland grassland and plantation forest. Addressing continued emissions from these areas could provide a high degree of emissions abatement, but would face significant logistical and socioeconomic barriers. Mitigation measures that reduce emissions from cultivated peatlands without leading to large-scale loss of income to farmers and landowners, or to a decrease in UK food security, thus represent a key scientific and policy challenge. In the meantime, the continued restoration of modified upland bogs, notably higher-emitting categories such as actively eroding areas and heavily degraded former domestic peat cutting sites, may represent more tractable options for emissions reduction.  

Whilst many individual components of the peatland emissions inventory remain uncertain, due to limitations in the number of primary measurement studies and difficulties in translating available soils and land-cover data into reliable peat area and condition estimates, the data and methods set out in this report provide the basis for initial inclusion of peatlands in the UK emissions inventory. To support the future development of this inventory, there is a need for new field-scale measurements of GHG fluxes from under-studied peatland types, and for the development of consistent, UK-scale condition mapping and monitoring approaches, potentially based on new earth observation data.