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Disentangling climatic and anthropogenic controls on terrestrial ET trends

September 8, 2015

Objective

Examine natural and anthropogenic controls on terrestrial evapotranspiration (ET) changes from 1982 to 2010.

Approach

  • We created a diagnostic tool combining ET information from 11 long-term datasets. All input datasets were based on extensive in situ observations, satellite retrievals, or both.
  • We used this diagnostic tool to evaluate single-factor and multi-factor simulations from the Multi-Scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP).

Spatial distribution of the dominant drivers for the ET. (a) Dominant drivers for the natural and human-induced ET, and (b) dominant drivers for the human-induced ET. CLI: the impact from historical climate only, OTH: all anthropogenic impacts, CO<sub>2</sub>: the historical CO<sub>2</sub> impact only, NDE: the historical nitrogen deposition impact only, LUC: the historical land use/land cover change impact only.

Spatial distribution of the dominant drivers for the ET. (a) Dominant drivers for the natural and human-induced ET, and (b) dominant drivers for the human-induced ET. CLI: the impact from historical climate only, OTH: all anthropogenic impacts, CO2: the historical CO2 impact only, NDE: the historical nitrogen deposition impact only, LUC: the historical land use/land cover change impact only.

Results/Impacts

  • Changing climate was assessed to be the dominant control on spatiotemporal variations in ET.
  • Rising atmospheric CO2 concentration was the second most important factor influencing ET, with higher CO2 driving a decreasing trend in ET.
  • Nitrogen deposition slightly amplified global ET via enhanced plant growth. Land-use-induced ET responses were minor globally but pronounced locally.
  • Multi-stream datasets and multi-modeling frameworks help to quantify the strengthening anthropogenic fingerprint on the global hydrologic cycle.

Mao, Jiafu, Wenting Fu, Xiaoying Shi, Daniel M. Ricciuto, Joshua B. Fisher, Robert E. Dickinson, Yaxing Wei, Willis Shem, Shilong Piao, Kaicun Wang, Christopher R. Schwalm, Hanqin Tian, Mingquan Mu, Altaf Arain, Philippe Ciais, Robert Cook, Yongjiu Dai, Daniel Hayes, Forrest M. Hoffman, Maoyi Huang, Suo Huang, Deborah N. Huntzinger, Akihiko Ito, Atul Jain, Anthony W. King, Huimin Lei, Chaoqun Lu, Anna M. Michalak, Nicholas Parazoo, Changhui Peng, Shushi Peng, Benjamin Poulter, Kevin Schaefer, Elchin Jafarov, Peter E. Thornton, Weile Wang, Ning Zeng, Zhenzhong Zeng, Fang Zhao, Qiuan Zhu, and Zaichun Zhu. September 8, 2015. “Disentangling Climatic and Anthropogenic Controls on Global Terrestrial Evapotranspiration Trends.” Environ. Res. Lett., 10(9):094008. doi:10.1088/1748-9326/10/9/094008.

Disentangling climatic and anthropogenic controls on terrestrial ET trends
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