Refining our understanding of wildfire during the Last Glacial-Interglacial Transition in the British Isles

Abstract

Centennial-to-millennial scale wildfire expression is often investigated as an aid to understanding potential future changes in patterns of biomass burning. The British Isles have been the focus of frequent palaeoenvironmental investigations; however, information on burning during the Last Glacial-Interglacial Transition (LGIT; c. 17-8.2 ka cal. BP), a period of multiple and in many cases abrupt climatic events, is limited. A literature review collated evidence of wildfire from 238 sites in the British Isles that spanned the LGIT and indicated that wildfire may have been a common component of the landscape, as charcoal, a common wildfire proxy, was widespread in sediments that span the LGIT. Evidence of burning during periods of possibly limited human impact, when the vegetation was not uniform, as well as evidence of contemporaneous burning on a regional scale, suggests an association between wildfire and climate. To further investigate this relationship, seven new high-resolution contiguous macroscopic charcoal records were obtained. For this purpose, procedures aiming to minimize charcoal loss were utilized, as determined via a systematic assessment of commonly used techniques, which indicated that statistically significant differences arise between different laboratory protocols. Cutting-edge algorithms were subsequently tuned to eliminate human selection parameter setting and, thus, Robust Fire Events were reconstructed for suitable records (four out of the seven new sites). The new data suggests no fire-free periods, as well as concurrent phases of burning on a regional scale, most of which coincide with known abrupt climate events. The findings, therefore, suggest that wildfire was a constant feature of the British Isles’ palaeolandscape during the LGIT, likely modulated primarily by climate, and further attest to possible increase in wildfire risk for the region under various climate change scenarios. Options to mitigate the risk, including the enhancement of wildfire risk reflection within the available wildfire prediction platforms, are also explored and discussed.

Date of Award	Jul 2021
Original language	English
Awarding Institution	University of Portsmouth
Supervisor	Mark Hardiman (Supervisor), Laura Kay Cunningham (Supervisor) & David Martill (Supervisor)