Increased hydroclimate variability in midlatitude Europe during the middle Eocene greenhouse

A high-resolution hydroclimate record from the Messel Pit Fossil Site (Germany) reveals that midlatitude Europe experienced significant variability in relative humidity during the middle Eocene greenhouse, partly decoupled from temperature changes. The study, using hydrogen and carbon isotopic composition of plant waxes preserved in varved sediments, shows that moisture sources varied due to fragmented paleogeography, with relative humidity fluctuating up to 60% between 47.7 and 47.2 million years ago. This variability decreased over time, coinciding with orbital insolation changes, suggesting a link between Earth's orbital cycles and hydroclimatic trends.

Schmitt, C., Vasiliev, I., Martínez-García, A., Meijer, N., & Mulch, A. (2026). Increased hydroclimate variability in midlatitude Europe during the middle Eocene greenhouse. Global and Planetary Change, 259, 105357. https://doi.org/10.1016/j.gloplacha.2026.105357