Figure 2

Annual methane emissions plotted against basal peat ages from closest vicinity locations (red dots, left axis). Furthermore, the GHG balance was calculated using a standard global warming potential (GWP) calculation (100 year GWP CH₄: 28) for methane in CO₂ equivalents combined with the annual fen CO₂ flux range from the 11-year eddy covariance dataset (upper + 23 g CO₂-C m⁻² year⁻¹, lower – 90 g CO₂-C m⁻² year⁻¹, respectively; Table S2) (light and dark green dots, right axis). Note the age range (0–100 years) depending on CO₂ sink strength where the fen ecosystem shifts from being a sink to a source of warming-inducing gases.