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Title: Present-day irrigation mitigates heat extremes

Irrigation is an essential practice for sustaining global food production and many regional economies. Emerging scientific evidence indicates that irrigation substantially affects mean climate conditions in different regions of the world. Yet how this practice influences climate extremes is currently unknown. Here we use ensemble simulations with the Community Earth System Model to assess the impacts of irrigation on climate extremes. An evaluation of the model performance reveals that irrigation has a small yet overall beneficial effect on the representation of present-day near-surface climate. While the influence of irrigation on annual mean temperatures is limited, we find a large impact on temperature extremes, with a particularly strong cooling during the hottest day of the year (-0.78 K averaged over irrigated land). The strong influence on extremes stems from the timing of irrigation and its influence on land-atmosphere coupling strength. Together these effects result in asymmetric temperature responses, with a more pronounced cooling during hot and/or dry periods. The influence of irrigation is even more pronounced when considering subgrid-scale model output, suggesting that local effects of land management are far more important than previously thought. In conclusion, our results underline that irrigation has substantially reduced our exposure to hot temperature extremesmore » in the past and highlight the need to account for irrigation in future climate projections.« less
Authors:
ORCiD logo [1] ;  [2] ; ORCiD logo [3] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [2]
  1. ETH Zurich (Switzerland). Inst. for Atmospheric and Climate Science; Vrije Univ. Brussel, Brussels (Belgium). Dept. of Hydrology and Hydraulic Engineering
  2. ETH Zurich (Switzerland). Inst. for Atmospheric and Climate Science
  3. National Center for Atmospheric Research, Boulder, CO (United States)
Publication Date:
Grant/Contract Number:
FC03-97ER62402/A010; SC0012972; 2015‐67003‐23489
Type:
Published Article
Journal Name:
Journal of Geophysical Research: Atmospheres
Additional Journal Information:
Journal Volume: 122; Journal Issue: 3; Journal ID: ISSN 2169-897X
Publisher:
American Geophysical Union
Research Org:
Univ. of Maryland, College Park, MD (United States). Univ. Corp for Atmospheric Research
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); US Dept. of Agriculture (USDA); National Center for Atmospheric Research (NCAR), Boulder, CO (United States); ETH Zurich (Switzerland); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 60 APPLIED LIFE SCIENCES; Irrigation; Climate; extremes
OSTI Identifier:
1342255
Alternate Identifier(s):
OSTI ID: 1342256; OSTI ID: 1427802