Recent warming in the Arctic has been compared with the large magnitude abrupt climatic warmings identified in the last glacial period suggesting we are witnessing an abrupt critical transition in the Arctic climate system. This theory is based around the study of modern and palaeo-events identified in both Arctic sea-ice records and within the Greenland ice sheet. We can assess the impacts of abrupt warming and test model outputs by assessing how past abrupt climatic transitions affected terrestrial landscapes in NW Europe. The Last Glacial Interglacial Transition (LGIT: ~ 19 to 8ka) was the most recent period of abrupt climate change affecting large-scale ocean and atmospheric systems, and provides a natural laboratory to understand the rate and magnitudes of environmental responses to abrupt changes. However, the rapidity of abrupt change means that 1) most terrestrial systems lack sufficient chronological precision to assess rates of change beyond centennial scale and 2) comparison between palaeo-records based on imprecise chronologies precludes assessment of phasing and spatial variability in environmental responses.
Recent advances have shown how annually-resolved (varve) lake chronologies can begin to answer these questions. Projects can be developed with the specific aim of improving spatiotemporal coverage and resolution of British LGIT archives, developing lithological proxy records from the varve sediments, and tying the sequences to absolute timescales.
Training will include use of deep-lake coring platform on British water bodies to recover LGIT sequences, preparation of material for thin section production to enable microfacies analysis of laminated sediments to produce varve chronologies. Core sequences will also be scanned for cryptotephra and radiocarbon dating to generate Bayesian age models.
Policy Impact of Research:
The use of varve chronologies in Britain lags that of continental Europe and Scandinavia. By undertaking this project, we will be able to better track the timing and pattern, but crucially understand the rate of glacier retreat during periods of abrupt climate change. This will inform policymakers on the likely response of modern glacier ice caps and icefields to atmospheric temperature increases that are predicted over the next century.