Science Source
Recent decline in the global land evapotranspiration trend due to limited moisture supply
- States more than half of the solar energy absorbed by land surfaces is currently used to evaporate water
- States climate change is expected to intensify the hydrological cycle and to alter evapotranspiration, with implications for ecosystem services and feedback to regional and global climate
- Provides a data-driven estimate of global land evapotranspiration from 1982 to 2008, compiled using a global monitoring network, meteorological and remote-sensing observations, and a machine-learning algorithm
- Results suggest that global annual evapotranspiration increased on average by 7.1 ± 1.0 millimetres per year per decade from 1982 to 1997
- Finds that after 1997, coincident with the major El Niño event in 1998, the global evapotranspiration increase seems to have ceased until 2008
- Finds the change was driven primarily by moisture limitation in the Southern Hemisphere, particularly Africa and Australia
- Analyzes microwave satellite observations, which indicate that soil moisture decreased from 1998 to 2008
- Finds increasing soil-moisture limitations on evapotranspiration largely explain the recent decline of the global land-evapotranspiration trend
- States that whether the changing behaviour of evapotranspiration is representative of natural climate variability or reflects a more permanent reorganization of the land water cycle is a key question for earth system science
