When sediment samples reveal the past’s secrets: James Zachos and Ellen Thomas win BBVA Climate Change Award

They are recognized for identifying a greenhouse effect 56 million years ago that serves to predict the destructive impacts of today’s human-induced global warming. The laureates were announced by Prof. Bjorn Stevens, award jury president and director at the Max Planck Institute for Meteorology, on 11 January 2023.

The jury recognized the two scientists in their statement: “For seminal contributions to the identification of a major natural event in the fossil record that provides a compelling analog for anthropogenic climate change. This event, known as the Paleo-Eocene Thermal Maximum (or PETM), took place about 56 million years ago. Zachos and Thomas convincingly demonstrated that the PETM was characterized by 5-6 °C of warming and coincided with the release of massive quantities of CO₂ and/or methane into the Earth’s atmosphere, resulting in major extinction of deep-sea organisms, and ocean acidification.

The PETM demonstrates the implications of a major perturbation of the global carbon cycle, one similar in magnitude to what is happening today. Their analyses of marine and terrestrial records, made available through the painstaking efforts of international drilling programmes, help bound Earth’s surface temperature sensitivity to increases in greenhouse gasses; reveal the multi-millenary time-scale over which natural processes remove carbon from the atmosphere; and contextualize present day changes with respect to the geological past.”