The temperature of Europe during the Holocene reconstructed from pollen data

We present the first area-average time series reconstructions of warmest month, coldest month and mean annual surface air temperatures across Europe during the last 12,000 years. These series are based on quantitative pollen climate reconstructions from over 500 pollen sites assimilated using an innovative four-dimensional gridding procedure. This approach combines three-dimensional spatial gridding with a fourth dimension represented by time, allowing data from irregular time series to be ‘focussed’ onto a regular time step. We provide six regional reconstructed temperature time series as well as summary time series for the whole of Europe. The results suggest major spatial and seasonal differences in Holocene temperature trends within a remarkably balanced regional and annual energy budget. The traditional mid-Holocene thermal maximum is observed only over Northern Europe and principally during the summer. This warming was balanced by a mid-Holocene cooling over Southern Europe, whilst Central Europe occupied an intermediary position. Changes in annual mean temperatures for Europe as a whole suggest an almost linear increase in thermal budget up to 7800 BP, followed by stable conditions for the remainder of the Holocene. This early Holocene warming and later equilibrium has been mainly modulated by increasing winter temperatures in the west, which have continued to rise at a progressively decreasing rate up to the present day.