Local climate impacts from ongoing restoration of a peatland – the Onlanden Experiment

We have shown that peatlands represent a cool humid island in their landscape context and that this cool humid island effect could be brought about by successful peatland restoration. However, it has been difficult to dis-entangle the controls on the direct climate impact of peatlands. Previous studies have been limited by a lack of pre-intervention data and the lack of significant target against which to test impact. The Onlanden, an area of peat south west of the city of Groningen, came under restoration management in 2012 when water tables were restored, but without active revegetation. The water table on the site was monitored before restoration and is ongoing and the area is . The direct climate impact of the restoration was assessed using remotely sensed land surface temperature, albedo and vegetation indices. Furthermore, the impact was modelled based upon a forced convection approach. The study can show that day time temperatures over the peatlands cooled relative to the surrounding land by up to 1.1 K (°C), but there was no significant change in night time temperatures. But there was a more dramatic change was observed for the peatlands the average amplitude of the diurnal temperature cycle decreased by upto 2.4 K (°C) over the period of the restoration.

The presence of an overall cooling effect means that a rising water table led to a lowering of the Bowen ratio. However, this result would suggest that open water would achieve an even greater cooling effect but would limit peatland development.