Temperate to tropical palaeoclimates on the northwest margin of Europe during the middle Cenozoic

Globally, the middle Cenozoic (Oligocene to early Miocene, similar to 33.9-15.97 Ma) was characterized by a warmer, wetter climate than present. Reconstructing the climate of this stratigraphic interval helps us to better understand the implications of present and future anthropogenically-driven climate change in an Earth system with an established Antarctic ice mass and comparable pCO(2) levels (400-700 ppm). Relative to mainland Europe, little palaeoclimate work has been done on the British Isles for this time interval. Compiled middle Cenozoic palynology records from across the British Isles were used to quantitatively reconstruct palaeoclimate, which was then used to define Koppen-Geiger signatures for each palynomorph assemblage. These reconstructions were used to show the presence of a temperate, dry-winter and hot-summer (Cwa) KoppenGeiger climate type before 31.8 Ma, which was possibly a short-lived event driven by precessional (similar to 26 k.y.) forcing. We attribute reconstructions with dry-winter Koppen-Chattian sections, are associated with the Svalbardella-2 and 3 North Sea cooling events. The late Oligocene warming event is shown to have produced tropical rainforest (Af) Koppen-Geiger classification types in the British Isles. Following early Miocene structed. We suggest the present-day climate of the northwest margin of Europe is comparable to the early Miocene palaeoclimate. Under increased pCO(2) concentrations, based on projected twenty-first century anthropogenic warming scenarios, there is potential for wetter summers becoming more prevalent within the next century.