Hydrology and Land Surface Studies
Uncertainty in the estimation of potential evapotranspiration under climate change
Article first published online: 31 OCT 2009
Copyright 2009 by the American Geophysical Union.
Geophysical Research Letters
Volume 36, Issue 20, October 2009
How to Cite
2009), Uncertainty in the estimation of potential evapotranspiration under climate change, Geophys. Res. Lett., 36, L20403, doi:10.1029/2009GL040267., , , , and (
- Issue published online: 31 OCT 2009
- Article first published online: 31 OCT 2009
- Manuscript Accepted: 15 SEP 2009
- Manuscript Revised: 8 SEP 2009
- Manuscript Received: 27 JUL 2009
- climate change;
- potential evapotranspiration;
 21st century climate change is projected to result in an intensification of the global hydrological cycle, but there is substantial uncertainty in how this will impact freshwater availability. A relatively overlooked aspect of this uncertainty pertains to how different methods of estimating potential evapotranspiration (PET) respond to changing climate. Here we investigate the global response of six different PET methods to a 2°C rise in global mean temperature. All methods suggest an increase in PET associated with a warming climate. However, differences in PET climate change signal of over 100% are found between methods. Analysis of a precipitation/PET aridity index and regional water surplus indicates that for certain regions and GCMs, choice of PET method can actually determine the direction of projections of future water resources. As such, method dependence of the PET climate change signal is an important source of uncertainty in projections of future freshwater availability.