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We hypothesize 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. This study used 20 years of Earth observation data for land surface temperature (day‐ and night‐ time LST), albedo (near infra‐red white sky albedo) and vegetation indices measured for 42 one km2 grid squares across two peatlands and their surrounding arable fields. The peatlands have undergone restoration (re‐vegetation and raising of water tables) since 2004. The results show that over the restored peatlands:Day time temperatures over the peatlands cooled relative to the surrounding arable‐land by up to 1.1 K (°C), but there was no significant change in night time temperatures.Over the peatlands the average amplitude of the diurnal temperature cycle decreased by up to 2.4 K (°C) over the period of the restoration.Comparison to vegetation indices and albedo shows the cooling effect of increasing albedo was smaller than warming effect of changes aerodynamic resistance brought about by development of shrubby vegetation.The presence of an overall cooling effect, despite a warming effect due to vegetation development, means that a rising water table led to a lowering of the Bowen ratio. Peatlands revegetated to, or dominated by, moss carpets rather than shrubby vegetation will maximise the potential cooling effect, whereas shrub development across peatlands without a rise in water table would lead to warming. [ABSTRACT FROM AUTHOR]

This study proposed that due to their high standing water tables that peatlands would be cold humid islands within their landscape, and especially so relative to farmland on mineral soils. To test this hypothesis, we measured air temperature and humidity at 17 locations along a 7.8 km transect across the UK's largest lowland raised bog from February 2018 to January 2019. Air temperature and humidity were measured hourly for 1 year and supported with spot albedo measurements. The study represented a factorial experiment with respect to sites of measurement, the type of land use (peat vs. arable land) and time of sampling over both the seasonal and diurnal cycles. We show that: (a) That although mean annual temperature was not significantly different between arable and peatlands, the arable land showed a decreased amplitude to its seasonal cycle – this is the reverse of the expected pattern. (b) The albedo of the peatland was significantly lower than that of arable land showing that vegetated peatland still absorbed more solar radiation. (c) The specific humidity was lower on the peatland than on the surrounding arable land. The study showed that while shrubby vegetation exists over a peatland then energy budgets are more likely to be dominated by the lower aerodynamic resistance and lower albedo of the vegetated peatland relative to arable land. Thus, shrub‐dominated peatlands will not be a cold humid island in their landscape. [ABSTRACT FROM AUTHOR]

Land use, land use change, and forestry (LULUCF) have been directly altering climate, and it has been proposed that such changes could mitigate anthropogenic climate warming brought about by increases in greenhouse gas emissions to the atmosphere. Changes due to LULUCF alter the Bowen ratio, surface roughness, and albedo and so directly change air temperatures. Previous studies have focused on changes in the area of forestry and have used space‐for‐time substitutions to assess the impact of LULUCF. This study considered 18 years of daytime land surface temperature over an area of actual land use change in comparison to its surrounding landscape and considered the restoration of a lowland peat bog: satellite land surface temperature data across 49, 1‐km2 grid squares with 20 on peatland and 29 on surrounding agricultural land on mineral soils from 2000 to 2017. The peatland squares were, until 2004, dug for horticultural peat and after 2004 were restored with revegetation of bare soil and restoration of natural water tables. Over the 18 years, the average annual daytime land surface temperature significantly decreased for six grid squares, five of which were on the restored peatland where land surface temperature decreased by 2 K. In 2000, before restoration, the peatland was 0.7 K warmer than the surrounding agricultural land on mineral soils but by 2016 was 0.5 K cooler. This study has shown that anthropogenic land use change could cool a landscape and that functioning peatlands could act as cool, humid islands within a landscape. Key Points: Peatland restoration led to reduction of air temperature relative to surrounding agricultural landAir temperature significantly decreased by 1.2 K over 18‐year period compared to surrounding landscapeFor 5 km2 of the peatland the relative decrease in air temperature was 2 K [ABSTRACT FROM AUTHOR]

Accurate estimates of methane (CH4) fluxes from restored peatlands are needed to inform emission factor estimations and reporting. Flux measurements are usually taken during the daytime but such measurements may provide biased estimates of overall CH4 emissions if night-time fluxes differ from daytime fluxes. Diurnal variations in CH4 fluxes have been reported for a range of peatland types, but not for restored raised bogs which are important carbon stores in some countries. To help fill this knowledge gap, we investigated diurnal variations in CH4 emissions from a restored raised bog. CH4 fluxes from a restored raised bog were measured in two 24-hr field campaigns using flux chambers. Carbon dioxide (CO2) fluxes were also monitored, as were a suite of complementary environmental variables. Night-time CH4 fluxes were significantly greater than daytime fluxes during both campaigns, by 10.4% and 36.1%, respectively. In Campaign 1 air temperature was the best predictor of CH4 fluxes, whereas in Campaign 2 net ecosystem exchange (NEE) values were the best predictor. This study shows that diurnal variations in CH4 fluxes exist in a restored peatland and that current approaches biased to daytime measurements will underestimate CH4 emissions from restored peatlands to the atmosphere. [ABSTRACT FROM AUTHOR]