By hoarding water underground, vegetation will help saturate soil, boosting rain runoff.
The next time a river overflows its banks, don’t just blame the rain clouds. Earth system scientists from the University of California, Irvine have identified another culprit: leafy plants.
In a study published today in Nature Climate Change, the UCI researchers describe the emerging role of ecophysiology in riparian flooding. As an adaptation to an overabundance of carbon dioxide in the atmosphere, trees, plants and grasses constrict their stomatal pores to regulate the amount of the gas they consume, a mechanism that limits the release of water from leaves through evaporation.
“Plants get more water-efficient and leak less underground soil moisture out through their pores in a carbon-rich atmosphere,” said study co-author Mike Pritchard, UCI assistant professor of Earth system science. “Add this up over billions of leaves in very sunlit, leafy places, especially the tropics, and it means there is a bunch more soil moisture stored up underground, so much so that climate models predict rainfall events will saturate the ground and more rain will run off into rivers.”
Pritchard said this so-called forest effect dominates atmospheric responses to CO2 on most land masses up to 30 degrees north and south of the equator, which is where most people live. And he noted that this plant-based phenomenon could have a large influence on flooding in the Mississippi River basin.
Continue reading at University of California Irvine
Image via NASA
