Peatlands: Carbon friend or foe?

Image Credit: Sinéad Mohan

The rewetting of bogland is a contentious subject, as the clear environmental advantages must be weighed against damage to agricultural lands and people’s livelihoods. Noel Barden takes a closer look at the issue.

With one fifth of the country’s landmass covered in peat soils, any discussion about climate-friendly agriculture, or the green economy as a whole, is bound to reference the immense potential for these lands to offset carbon emitted from industry, transport and agriculture. Often marginal in their agricultural output and with limited other land use, such peats may become a lucrative asset to rural landowners in sequestering carbon.

Effective sequestration can only be achieved through a reversal of the large-scale draining of raised boglands that began in the 1930, as the use of the peatlands for energy generation intensified. Drains can be blocked, allowing the water table to rise, returning conditions to their original anaerobic state. The emissions of CO2 from this rewet bogland reverses as the peat becomes a net holder of carbon. Methane from the peat does rise during the process, although not to an extent that it tips the carbon balance and returns the land to a net contributor of emissions. This is an important note for future emission inventories, should the rewetting proceed on a large scale and a rise in national methane be measured.

It is this process of rewetting that is the point of contention for many landowners, as tracts of farmland surrounding the rewetted bogs may have been taken to reasonably high levels of agricultural productivity through decades of intergenerational land improvement efforts. The flooding of these surrounding lands as the local water table rises, as well as the possible need to relocate the residents of neighbouring areas, will be a tough sell for politicians. 

Further job losses in midland populations with economic dependence on peatlands, farmed or otherwise, should be avoided in proposed rewetting efforts as support from rural communities is essential in the success of such schemes. Many peatland repurposing proposals are viewed cautiously, following the disappointment of many in the early closure of the ESB’s West Offaly and Lough Ree power plants. Questions have been raised as to the credibility of a “Just Transition” to renewable energy with the unexpected mass lay-offs at both of the power stations, as well as at Bord na Mona, the main peat supplier of these electricity stations. Rewetting projects must consider the social sustainability of their efforts if proponents wish for adoption at a wider level throughout the country.

The inclusion of actively sequestering boglands in the cap and trade carbon credit system may aid the economic justification of rewetting measures. Rewetting could compete with conifer afforestation, a non-biodiverse carbon friendly land use. Marginal lands with little to no population could begin rewetting before these areas of potential disagreement, beginning the rewetting process quicker. 

There are other environmental advantages to the restoration of peatlands through rewetting, aside from carbon retention. Almost half of the endangered bird species in Ireland are found in peatland habitats. As much of the native flora and fauna are also dependent on them for their ecological niche, the conservation of existing boglands and the restoration of drained bogs is essential for the protection of biodiversity.

2,500 hectares of boglands have been rewet by Bord na Mona, showing the feasibility of the restoration method in Irish conditions. Cutaway bog can regenerate whilst a complement of ecosystems successfully establish themselves in areas where the landscape was reshaped by decades of peat removal. Bord na Mona has recorded over 25 separate plant communities in cutaway bogland, once rewet.

The rewetting may have other favourable tangible benefits. Met Eireann forecasts an increased frequency of extreme weather events and less stable weather patterns with ever increasing global temperatures. Bogs, which are 95-98% water in composition, have a hugely underutilised capacity to store large volumes of water. The retention of precipitation from the peatlands’ catchment areas in times of heavy rainfall may help lessen the incidence and severity of flooding in urban areas prone to fluvial flood damage. The continued investment in capital-heavy flood protection infrastructure, which often has questionable efficacy, must be assessed as flooding in many riverside areas is semi-routine.

The adoption of such changes in land use have the potential to restore areas of ecological sensitivity, mitigate against flood damage and act as a major carbon sink. The Open Call led by Pippa Hackett, Minister of State for Agriculture with responsibility for land use and biodiversity, for a locally led rewetting scheme may offer up a solution that will be favourable to environmentalists and rural communities alike.