Project 5:
Early Human-climate interactions
We have been actively engaged in interdisciplinary research on the role of humans in Earth’s history. We have contributed both ideas and modelling expertise to this developing topic through collaborations across UCL with archaeologists, geologists and geneticists. Our expertise on the Plio-Pleistocene climate has led to Dr Brierley collaborating on research around potential climate impacts on Human evolution. We have also fostered uniquely interdisciplinary research on the impacts that human actions have had on the climate system prior to industrialisation, especially associated with proposed early start dates for the Anthropocene at 5,500 years ago and 1610 C.E.
Our 2019 paper provides a holistic assessment of the climate impact of the colonisation of the Americas. It combines a thorough review of archaeological evidence for population in land use prior to 1492 with paleo-epidemiological evidence of population decrease and the subsequent cessation of agriculture. Using state-of-the-art biogeochemistry and ecology, it estimates the role that the ensuing reforestation had on the global carbon cycle. The paper received significant press coverage and was the 48th most talked about piece of science in the world in 2019 (according to Altimetric). It has inspired an interdisciplinary workshop in Germany, has become required reading on palaeoclimatology courses internationally, and has already been cited nearly 150 times.
Prior to 5,500 years ago the Sahara was less arid and supported a growing human population. There was a subsequent climate transition and population collapse, which was coincident with the proposed start of the early Anthropocene. In our 2018 paper, a simple model was trained to predict the climate transition probabilistically. This was used to demonstrate that humans had not accelerated the climate transition; if anything, they delayed it by about 500 years. We further explored the role of pastoralism, providing a precedent for it as a useful adaptation to increasingly arid conditions. The work was written about in the i-newspaper and Dr Brierley was interviewed on the World Service.
- Brierley, C., Manning, K., & Maslin, M. (2018). Pastoralism may have delayed the end of the green Sahara. Nature Communications, 9(1). http://doi.org/doi:10.1038/s41467-018-06321-y
- Koch, A., Brierley, C., Maslin, M. M., & Lewis, S. L. (2019). Earth system impacts of the European arrival and Great Dying in the Americas after 1492. Quaternary Science Reviews, 207, 13-36. http://doi.org/10.1016/j.quascirev.2018.12.004