2.1.8 Part 2: Peatland Degradation & Carbon Losses

How do drainage and peat extraction shift peatlands from carbon sinks to carbon sources?

Lowering the water table exposes anaerobic peat layers to oxygen. Aerobic microbial decomposition oxidises ancient organic matter, releasing CO₂ and methane.

What is the carbon emission rate of commercially extracted or heavily drained peatlands?

Extracted peatlands emit 5 to 20 tonnes of CO₂/ha/year. Drained agricultural peatlands (e.g., East Anglian Fens) lose over 10 tonnes C/ha/year, with soil shrinkage rates up to 30 cm/century.

What impact did historical drainage have on the Exmoor Mires carbon store?

Drainage "grips" cut since the 19th century lowered water tables by 10–30 cm, shifting the mires from a sink (+0.2 to 0.5 t C/ha/year) to a source emitting 2 to 5 tonnes CO₂/ha/year.

What climate risk is illustrated by the 2018 Saddleworth Moor fire in the Peak District?

Degraded, dried peatlands become highly flammable