Unveiling the Secrets of Peatlands for Climate Change Mtigation

The Scottish peatlands (i.e. mires, fen and bog) cover about 20% of the country, storing approximately 1600 million tonnes of carbon in the soils, and therefore, represent an essential component of GHG budget at the Holocene time scale (Frolking et al., 2006). Peatlands also play important roles in water quality and supply, host a range of unique species, provide spaces for recreation and preserve a record of past environments and human activity (Bain et al., 2011). However, it is estimated that over 80% of the Scottish peatlands are degraded (Scotland soils, 2022). Un-degraded peatlands accumulate soil organic matter and act as a sink ecosystem for atmospheric CO2 due to the absence of aerobic decomposition and associated CO2 emissions under waterlogged soil conditions (Dise, 2009). Nevertheless, managed peatlands (e.g. drained and cultivated or afforested) show a high variability in GHG emissions at both spatial and temporal levels due to active systems in soil moisture dynamics, redox potential, availability of substrate materials and man-made alterations to hydrology and vegetation (Schrier-Uijl et al., 2010; Abdalla et al., 2014; Abdalla et al., 2016). There is a concern that degraded peatlands may significantly exacerbate anthropogenic climate change through release of CO2 from soils (Hooijer et al, 2010). This concern is currently motivating extensive attempts to conserve and restore peatlands in Scotland and around the world. On one hand, restoring degraded peatlands can reconnect them to their catchments and thereby, decreases CO2 emissions and increases carbon storage (Horsburgh et al., 2022). On the other hand, restoration by rewetting increases CH4 emissions (which has a higher radiative forcing than CO2) by 46% compared to the original pre-management CH4 emissions (Abdalla et al., 2016). However, it is still not clear how restoration affects net GHG emissions (i.e. balance between GHG emissions and carbon storage). This project will use experimental data, process modelling and meta-analyses to assess net GHG emissions by investigating both GHG emissions and carbon storage to fill this gap in knowledge. Further, the attribution of GHG emissions to anthropogenic and natural drivers is a great challenge, and is a prerequisite to successfully assess the potential to reduce the emissions from peatlands.

To the best of our knowledge, until this date, the impact of degraded or restored Scottish peatlands on net GHG emissions under baseline and climate change are not fully quantified/ mapped, nor potential restoration techniques modelled. This study will achieve the following objectives:
1) Create maps of baseline annual net GHG emissions from the Scottish peatlands; 2) Create maps of annual net GHG emissions from peatlands under climate change; 3) Map and investigate the impacts of drainage/ restoration on net GHG emissions; and 4) Investigate sensitivity of GHG emissions from the Scottish's peatlands to anthropogenic and natural drivers.