Asia, Europe and America could face increased floods due to shrinking plant leaf pores

Researchers attached with the UK Met Office and the UK Centre for Ecology and Hydrology have warned that Asia, Europe and North America could experience worse flooding in the future because of carbon dioxide sensitive plants consuming less water.

Washington, Aug.30 : Researchers attached with the UK Met Office and the UK Centre for Ecology and Hydrology have warned that Asia, Europe and North America could experience worse flooding in the future because of carbon dioxide sensitive plants consuming less water.

The researchers said this activity results in more water remaining in the soil and running off into rivers.

Two researchers -- Nicola Gedney and Richard Betts, and some of their other colleagues - have opined that tiny pores on the surface of some plant leaves are sensitive to carbon dioxide, and this might contribute significantly to future flooding because of an increase in atmospheric pollutionThese pores, they claim, will help in predicting which regions are at greatest risk to flooding because of global warming.

Called the "Stomata Effect", Betts and colleagues warn in their study, which appears in Nature, that climate change and plant leaf reaction could see 13 to 24 percent of Asia, Europe and North America being exposed to increased flooding, instead of the expected 11 to 16 percent.

The tiny pores, or stomata, are found on the surface of leaves and are each between a tenth and several hundredths of a millimetre across. The underside of black oak leaves can have as many as 60,000 stomata per square centimetre.

The main function of stomata is to regulate the amount of carbon dioxide taken up by the plants during photosynthesis.

In an earlier study, Gedney and his team analysed river flow during the 20th century to see how shrinking stomata might affect its run-off.

They found that river flow had increased by three percent worldwide during the 20th century and calculated that this must be due to increased soil moisture resulting from shrinking stomata.

Since the late 19th century, atmospheric CO2 has risen from 280 to 390 parts per million as a result of humans burning fossil fuels and chopping down forests.

The net effect of reduced transpiration is that plants consume less water - meaning more remains in the soil and can run off into rivers.

The researchers used computer models to assess the effects of global warming on river run-off, through increased rainfall and other factors.

They looked at what these effects will be if CO2 levels reach 560 ppm. This is double what levels were before the industrial revolution and is expected to happen sometime in the second half of the 21st century.

The team then ran the same models again, this time switching on the "stomata effect".

"Where climate change is predicted to increase river flow, the biological effect (of the stomata) will increase river flow further," says Betts.

The researchers also performed a regional analysis. They predict that there will be a positive impact on some regions, The Mediterranean and South America regions, they said should suffer a little less because soil will contain more water than predicted by current climate change models.

ANI