Substantial cuts in global greenhouse gas emissions could be achieved by raising water levels in agricultural peatlands, according to a new study in the journal Nature. A team of researchers led by the UK Centre for Ecology & Hydrology estimates halving drainage depths in these areas could cut emissions by around 500 million tonnes of carbon dioxide (CO2) a year, which equates to 1 per cent of all global greenhouse gas emissions caused by human activities.

Peatlands occupy just three per cent of the world’s land surface area but store a similar amount of carbon to all terrestrial vegetation, as well as supporting unique biodiversity.

In their natural state, they can mitigate climate change by continuously removing CO₂ from the atmosphere and storing it securely under waterlogged conditions for thousands of years.

But many peatland areas have been substantially modified by human activity, including drainage for agriculture and forest plantations. This results in the release, from drained peatlands, of the equivalent of around 1.5 billion tonnes of carbon dioxide (CO₂) into the atmosphere each year — which equates to three per cent of all global greenhouse gas (GHG) emissions caused by human activities.

A team of scientists, led by the UK Centre for Ecology and Hydrology (UKCEH), estimated the potential reduction in emissions by restoring all global agricultural peatlands. However, because large populations rely on these areas for their livelihoods, it may not be realistic to expect all agricultural peatlands to be fully rewetted and returned to their natural condition in the near future.

The team therefore also analysed the impact of halving current drainage depths in croplands and grasslands on peat — which cover over 250,000km² globally — and showed that this could still bring significant benefits for climate change mitigation. The study estimates this could cut emissions by around 500 million tonnes of CO₂ a year, which equates to 1 per cent of all global GHG emissions caused by human activities.

Story Source:
Materials provided by UK Centre for Ecology & Hydrology. Original written by Simon Williams. Note: Content may be edited for style and length.