How evolving plants transformed Earth’s water cycle during its last ice age.
A new paper by Will Matthaeus, Jenny McElwain, and colleagues, published in Global Ecology & Biogeography, examines how vegetation change influenced water balance during the Late Palaeozoic Ice Age. Using the paleo-ecosystem model Paleo-BGC v2.0, driven by CESM climate simulations for approximately 300 million years ago, the study examines how plant functional traits influenced hydrology under ancient icehouse conditions.
By comparing wet-adapted and dry-adapted plant types based on fossil trait data, the research shows that the shift toward drought-tolerant vegetation reduced runoff by up to 36%. This indicates that vegetation change alone had a major effect on water availability, independent of atmospheric CO₂ levels.
The findings highlight how plant evolution shaped Earth’s water cycle, reinforcing the spread of drought-tolerant species while limiting water-dependent lineages. The work forms part of the ERC-funded TERRAFORM project, led by Professor Jenny McElwain, which investigates how plants have transformed Earth system processes through geological time.
Read the paper here: Global Ecology & Biogeography