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Flowers & Rainfall

July 13, 2010

Flowering plants keep the world cooler and wetter than it would be otherwise.


Flower-powered rainfall. I’m Bob Hirshon and this is Science Update.

Without flowers, the world would be a little more drab. It would also be a lot drier and hotter, according to University of Chicago paleontologist Kevin Boyce. He explains that the leaves of flowering plants have a much higher vein density than any other plants, past or present.

KEVIN BOYCE (University of Chicago):
And that matters // because in order to take in carbon dioxide, they have to be able to lose the water. And the more veins they have, the more water they’re capable of losing.

That water comes out through the leaves, evaporates, and eventually returns as rain. Using climate models, Boyce and his colleague Jung–Eun Lee showed that just replacing flowering plants with non-flowering types would dramatically decrease rainfall around the world. It’s a step toward learning how flowering plants shaped today’s climate. I’m Bob Hirshon, for AAAS, the science society.