GEN-ERIC News

Global warming may carry a higher risk of flooding than previously thought, according to a study released on Wednesday by the British science journal Nature. It says efforts to calculate flooding risk from climate change do not take into account the effect that carbon dioxide (CO2) — the principal greenhouse gas — has on vegetation. Plants suck water out of the ground and “breathe” out the excess through tiny pores, called stomata, in their leaves. Stomata are highly sensitive to CO2. The higher the level of atmospheric CO2, the more the pores tighten up or open for shorter periods. As a result, less water passes through the plant and into the air in the form of evaporation. And, in turn, this means that more water stays on the land, eventually running off into rivers when the soil becomes saturated.