Reconstructing Terrestrial Paleoclimates: A Comparison of the Co-Existence Approach, Bayesian and Probability Reconstruction Techniques Using the UK Neogene

Neogene sediments in the UK are ideally situated for understanding the early development of hydrological dynamics and atmospheric circulation that led to the modern oceanic climate of northwest Europe. Onshore Neogene fossiliferous deposits in the UK are limited to the solution pipe fills at Trwyn y Parc in Anglesey (Middle Miocene), the Brassington Formation of Derbyshire (Serravallian-Tortonian), and the Coralline Crag Formation (latest Zanclean-earliest Piacenzian) and Red Crag Formation (Piacenzian-Gelasian) in southeast England. Palynoflora from these localities can be used to provide snapshots into the climate at the time of deposition, however, palaeobotanical-based reconstructions are typically lacking in their poor estimation of error. Therefore, we present the first pre-Quaternary application of two terrestrial climate reconstruction techniques: CREST (Climate Reconstruction SofTware) and CRACLE (Climate Reconstruction Analysis using Coexistence Likelihood Estimation), that use Bayesian and likelihood estimation probability respectively to generate a new palaeoclimate reconstruction, and compare this to Co-existence Approach reconstructions from the UK and continental Europe. Our study shows how Mean Annual Temperature (MAT) declines by 3 degrees-6 degrees C, Mean Annual Precipitation (MAP) declines by 480-600 mm and Precipitation Seasonality approximately halves throughout the Neogene. CREST and CRACLE reconstructions overlap with the Co-exisence Approach and have the advantage of providing uncertainty, rather than ranges. The UK appears to have had a milder, wetter, and less seasonal climate than continental Europe. This is likely due to the buffering effects of the Atlantic Ocean and North Sea ameliorating the UK Neogene climate despite regional and global changes in atmospheric and oceanic circulation.