The role of peatlands in global and regional drinking water resources

Water provision is a valuable ecosystem service that is of central importance to human well-being. Peatlands are potentially important to the sustainable provision of potable water because water draining from peatlands is often of good quality, other than being rich in dissolved organic carbon (DOC). However, there have been no attempts to date, to investigate the role of peatlands in potable water supply at a global scale. In this thesis, an improved global peatland map (PEATMAP) was developed, which is freely available as a potentially useful tool for peatland or wetland researchers. The new map provided a basis from which to estimate global hotspots of peatland-derived potable water use. The volume of annual drinking water delivered by these catchments was estimated, and the status of the water-supply peatlands were evaluated, being the first such estimates at the global scale. Application of PERSiST and INCA-C models across the nine catchments in the UK, which are among the most important peatland-derived drinking water supply catchments in the world, provided evidence of the potential changes in DOC concentration and DOC flux under 21st-century climate and sulphate deposition scenarios. The results show that total global peatland area is 4.23 million km2, approximately 2.84 % of the world land area. Water supply peatlands provide approximately 4.22 km3 yr-1 of peat-fed drinking water globally, equivalent to typical consumption of 71.4 million people, but only 28 % of water-supply peatlands are pristine or protected globally. Although DOC flux is largely insensitive to future climate change scenarios, DOC concentrations in UK water sources are likely to increase while discharges are likely to decrease under all 21st-century climate and sulphate deposition scenarios tested.