Life Cycle Assessment (LCA), assessing the “cradle-to-gate” emissions from milk production, guides both policy and farm-level decisions. When peatlands are turned into pastures, the emissions are commonly not included in the carbon footprint from milk produced on such areas.
Peat soils account for one third of the world’s soil carbon, which is approximately twice as much carbon as the biomass of all forests. Most peatlands have undergone extensive drainage for agricultural purposes, turning them from highly important carbon sinks to one of the largest human-induced sources of GHG emissions worldwide.
Recent research led by Anna-Lena Müller at the Karlsruhe Institute of Technology (KIT) reveals that this shortcoming significantly underestimates the climate impact from milk production.
“If these emissions are included in LCA-studies, peatlands always become the dominant emission source from dairy farming,” Müller explains. “It shifts the whole picture. If we’re discussing carbon footprints without considering the impact of drained peatlands, we’ll obtain a distorted picture.”
Müller and her colleagues recently published a literature review of existing LCA studies, with a specific focus on European milk production. It reveals a significant gap in specific LCA studies addressing the role of drained peatlands in milk production. Another study, which is currently under review aims to contribute closing this gap by analysing three structurally distinct dairy farms in the pre-alpine region of Bavaria by considering peatland-derived emissions, using a cradle-to-farm-gate LCA approach.
The research is a part of the research project CircAgric-GHG, that aims to enhance circularity and reduce GHG emissions from farms.
Three different methodologies were applied to estimate peatland emissions from the case study farms:
1. IPCC Tier 1 default emission factors – general but widely applicable
2. IPCC Tier 2 Implied emission factors for organic soil in Germany – tailored to German conditions, and accounting for variability in emissions based on land use, soil type and water table depth (WTD).
3. Farm-specific water table depth (WTD) modeling – using site-specific water table data to obtain farm-specific emission factors.
The emissions on farm level significantly increased the CF from all dairy farms in the study. The highest increase was seen when using the WTD-based approach (3.), that estimates the average water table depths of the peatland area on each farm.
“Even a few centimeters in water table depth can have a huge impact on CO₂ emissions,” Müller notes. “Methodology matters. The more specific the data, the better.”
The results were striking. Including peatland emissions at least doubled the carbon footprint of milk production on average. In upscaled scenarios, with larger areas of the farmland defined as peatland, the footprint did even increase up to 6.5 times in one case. This was done to illustrate the potential CF of farms with up to 100 % of their agricultural land relying on drained peat soils.
A major barrier to accurate LCA modelling is the lack of accessible data—especially water table depth at farm level.
“We had to rely on modelled maps and farmer knowledge,” Müller explains. “But access to this data is restricted, even within research institutions.”
Moreover, political sensitivities around peatland use complicate collaboration.
“Some farmers are afraid that sharing data could lead to regulatory consequences,” she adds.
To address these challenges, Müller and her colleagues advocates for a standardized methodology to include peatland emissions in all agricultural LCAs.
The literature review highlights a significant challenge with regards to international climate reporting to the United Nations. Soil and peatland emissions fall under the LULUCF (Land Use, Land-Use Change, and Forestry) sector, which is separated from agricultural reporting.
The authors encourage a critical reassessment of current reporting standards.
“At the very least, peatlands utilized for dairy production must be included in international and national agricultural LCA analysis, only then can we have a transparent basis for decision-making,” says Müller
So, what should be done on the ground? Müller highlights some innovative practices already being tested by farmers. These methods either decrease carbon emissions from peatlands, and/or lower the emissions from other sources or the farm:
One farmer in the study, despite operating the most intensive farm, achieved the lowest carbon footprint through a combination of these measures.
“It shows there are other measures that can be combined with rewetting,” Müller emphasizes. She calls for supportive policies that ensure farmer profitability while promoting climate-smart land use.
By; Anette Tjomsland Spilling
Published 17.09.25
