Sensitivity of global climate model simulations to increased stomatal resistance and CO2 increases

Increasing levels of atmospheric CO₂ will not only modify climate, they will also likely increase the water-use efficiency of plants by decreasing stomatal openings. The effect of the imposition of "doubled stomatal resistance' on climate is investigated in off-line simulations with the Biosphere-Atmosphere Transfer Scheme (BATS) and in two sets of global climate model simulations: for present-day and doubled atmospheric CO₂ concentrations. The anticipated evapotranspiration decrease is seen most clearly in the boreal forests in the summer although, for the present-day climate (but not at 2 × CO₂), there are also noticeable responses in the tropical forests in South America. -from Authors