Unlocking records of past permafrost thaw through isotopes of fossil bones

Palaeo-Thaw is a Leverhulme Trust funded (2021-2025) research project between researchers at University College London, the University of Leeds and the University of Sussex. The project aims to develop fossil bone isotope signatures as a new proxy for creating high-resolution chronologically-constrained records of past permafrost thaw.

Permafrost (ground which remains frozen for a least two consecutive years) holds vast stores of carbon. When frozen, this carbon is isolated from the Earth’s atmosphere, but as our climate warms and permafrost thaws, it gets released as greenhouse gases, which further contribute to climatic warming. Permafrost thaw also destabilises landscapes, increasing the risk of erosion and landslides, which can damage homes, infrastructure, and transport networks.

To better predict and plan for changes to our permafrost landscapes in the future, processes of permafrost thaw need to be better understood. The past offers an important window through which we can do this. At the end of the last ice age, permafrost thawed across vast regions of Eurasia and North America. The record of this permafrost thaw may have been passed on to animals that lived at this time and recorded in the chemistry of their bones. Our project will confirm this through studying soils, plants and animals in present day thawing permafrost environments and will then reconstruct records of past permafrost thaw. Establishing how quickly permafrost responded to temperature changes at the end of the last ice age will play an important part in informing us about the likely rate and nature of permafrost thaw in the future as our climate warms.