A new study by scientists at agricultural research and advisory body Teagasc claims Environmental Protection Agency estimates of greenhouse gas emissions from drained peatlands are hugely overstated, due to an overestimation of the amount of drained peat grassland in the country.
The study finds that significant portions of the 335,000 hectares of land estimated in the EPA National Inventory to be drained peat-based grassland, may not in fact be drained at all, or if they were drained may have rewetted naturally through abandonment, or maintenance failure of drainage systems.
The net effect of this according to the scientists would be to reduce the estimated carbon emissions from this sector from 7-9.3 million tonnes of Co2 equivalent per annum to 3.6-4.7 million tonnes.
The study published in the Journal of Environmental Management, looks back at pre internet records of drainage studies and reports from government-led land improvement campaigns in the country.
The Teagasc scientists say that when estimating emissions from organic soils for the National Inventory, it was assumed that all "managed" organic soils are uniformly artificially drained and 100% of the drainage network is functional, where no information is available to counteract this assumption.
However they say that based on their research and recently unearthed information, much of the 335,000 hectare grassland area on organic soils, assumed in Ireland, was never effectively drained in the first place and where it was, lack of maintenance has led to natural rewetting even though the land that is classified technically as "in production".
Read more: Farmers worried over impact of re-wetting peatlands
Dr Pat Tuohy of Teagasc explained: "While large areas of peatland have been transformed from their natural state to grassland agriculture, there is no evidence to support that effective drainage ever occurred on as much land as previously assumed.
"The drainage status of all grassland peat soils requires further investigation."
Professor Owen Fenton, also from Teagasc, added: "This study has proposed these potential emission savings by compiling decades of evidence related to drainage status of peat soils.
"We uncovered data in national scientific literature and reports, which enabled a more accurate national figure for drainage status to be proposed."
The study comes as rewetting of peat based grassland has become hugely controversial, as EU plans for rewetting a portion of those lands as part of nature restoration legislation make their way through the European Parliament and Council.
Read more: How much of Ireland is actually made up of peatland?
