Why Rainfall Frequency Matters More Than You Think
A new study published in Nature Communications (2025) shows that less frequent rainfall (not just less total rain) can lead to earlier autumn leaf senescence (leaf aging and fall) across the Northern Hemisphere.
When rain events become less frequent:
Soil moisture drops
Air becomes drier (higher vapor pressure deficit)
Plants shed their leaves earlier due to increased drought stress
They also acclimate faster to drought, which shortens their growing season
Perhaps most importantly, the study found that many global climate models fail to capture this effect, missing a critical piece of how ecosystems respond to climate change. Climate and vegetation models must consider how often it rains, not just how much. This could greatly improve our predictions of future ecosystem health and carbon dynamics.
