Image description: sunset over a peat bog in the Scottish Highlands. Image by  K B / Unsplash 

To improve our understanding of the conditions needed to restore peatlands, Professor Graeme Swindles from the School of Natural and Built Environment at Queen’s University has been leading a team to calculate peat accumulation rates over the past 2,000 years. They have been studying cores from 28 peat bogs across Europe.

Peatlands are carbon heroes

Peatlands form where there is a sustained build-up of partially decomposed plant matter, and they play a very important role in locking away greenhouse gases and absorbing industrial pollution.

In Europe, peatlands contain approximately five times more carbon than its forests, and around half of Europe’s soil carbon. However, human activities including pollution, draining and climate change have significantly threatened and destroyed Europe’s peatlands.

The study’s findings

Their study identified European peatlands need a combination of warm temperatures and a water table of around 10 cm to thrive.

The fastest peat accumulation (almost 0.5 cm per year) was around the Baltic Sea, at sites in Denmark, Poland, Sweden, and Finland which experience warm and humid summers.

In contrast, the slowest peat accumulation was measured in northern Sweden, which experiences cold winters and a short growing season.

Across all sites, peat accumulated fastest in regions with warm summer temperatures, which improves plant growth, and a water table around 10 cm below the surface. If the water table is too high, plants struggle to grow, and if the water table is too low, decomposers can rapidly break down peat as it develops.

Lead author Professor Swindles says the study suggests warmer summer temperatures could boost growth rates in European peatlands, but only if the water table stays high enough.

He also suggests previous peatland restoration programs should be evaluated to determine if their relative successes or deficiencies support these findings.