ABSTRACT
Peat formation is widespread across the globe but the majority of existing proxy climate records come from the ombrotrophic (rain-fed) raised and blanket peat bogs of temperate oceanic regions such as northwest Europe. In North America, peat initiation dates and the spread of peatlands have also been used to infer climate change during the Early to Mid-Holocene. Elsewhere, continuous records of change have been derived from profiles which may span most of the Holocene. Methods focus on the use of biological proxies, ideally used in a multi-proxy approach, to derive continuous bog surface wetness (BSW) curves which are an integrated record of effective precipitation, and on stable isotope measurements which may be directly influenced by temperature and precipitation. Both approaches have been used on recent peats in attempts to validate and calibrate the proxy records against documented climate records with some success, and the results suggest that the impact of summer temperatures on evapotranspiration from bog surfaces is the main factor in changes in BSW in northwest Europe. Within this region, changes in BSW are apparent in many sites at around 8200, 5900, 4400, 3500, 2700, 1700, 1400, 1100, 700 and 250 cal BP. These changes to a cooler/wetter climate are probably caused by circulation changes in the Atlantic Ocean and by solar variability. Ongoing research is providing decadal resolution records of proxy climate which may be used in testing climate models.
