1. How will climate change influence evapotranspiration? Matt Roby

2. Introduction Climate change will alter flows of water, energy, and carbon between the biosphere and the atmosphere Evapotranspiration = plant transpiration + soil evaporation How will projected changes in temperature, land-use, and atmospheric CO2 influence evapotranspiration?

3. The Midwest is vulnerable to climate change Rain-fed agriculture Crops selected for a specific climate Soil and water quality

4. Evapotranspiration is the sum of transpiration and evaporation http://blogs.oregonstate.edu/jonperry/files/2011/07/evapotra nspiration1.jpg

5. How will changing temperature influence evapotranspiration? Mean air temperature Diurnal temperature range Growing season duration

6. Effects of changes in mean air temperature Atmospheric demand for moisture Vapor pressure deficit drives evapotranspiration 1°C increase in air temperature produces a 6 – 7 % increase in the vapor pressure deficit “Thirsty” atmosphere Increased evapotranspiration (Kirschbaum 2004)

7. Decrease in the diurnal temperature range Midwest: warmer nights Reduction in diurnal temperature range Reduction in transpiration rate (Kirschbaum 2004).

8. Extended growing season Longer growing seasons in the Midwest, US Potential for increased evapotranspiration (Bagley et al. 2015) 2049-2068 climate

9. Effects of land-use change Climate change may encourage the expansion of new and different crops with their own biophysical properties Leaf-area-index (LAI) Canopy density Canopy albedo (Le et al. 2015)

10. Summary Climate change will alter flows of water, energy, and carbon between the biosphere and the atmosphere Temperature Land-use change Interactive effects Feedbacks