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Title: Potential bias of model projected greenhouse warming in irrigated regions

Abstract

Atmospheric general circulation models (GCMs) used to project climate responses to increased CO{sub 2} generally omit irrigation of agricultural land. Using the NCAR CAM3 GCM coupled to a slab-ocean model, we find that inclusion of an extreme irrigation scenario has a small effect on the simulated temperature and precipitation response to doubled CO{sub 2} in most regions, but reduced warming by as much as 1 C in some agricultural regions, such as Europe and India. This interaction between CO{sub 2} and irrigation occurs in cases where agriculture is a major fraction of the land surface and where, in the absence of irrigation, soil moisture declines are projected to provide a positive feedback to temperature change. The reduction of warming is less than 25% of the temperature increase modeled for doubled CO{sub 2} in most regions; thus greenhouse warming will still be dominant. However, the results indicate that land use interactions may be an important component of climate change uncertainty in some agricultural regions. While irrigated lands comprise only {approx}2% of the land surface, they contribute over 40% of global food production. Climate changes in these regions are therefore particularly important to society despite their relatively small contribution to average globalmore » climate.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
897972
Report Number(s):
UCRL-JRNL-221969
TRN: US200706%%163
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Resource Relation:
Journal Name: Geophysical Research Letters, vol. 33, N/A, July 14, 2006, L13709, doi:10.1029/2006GL026770
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; AGRICULTURE; CLIMATES; FEEDBACK; FOOD; GENERAL CIRCULATION MODELS; GREENHOUSE GASES; IRRIGATION; LAND USE; MOISTURE; PRECIPITATION; PRODUCTION; SOILS

Citation Formats

Lobell, D, Bala, G, Bonfils, C, and Duffy, P. Potential bias of model projected greenhouse warming in irrigated regions. United States: N. p., 2006. Web. doi:10.1029/2006GL026770.
Lobell, D, Bala, G, Bonfils, C, & Duffy, P. Potential bias of model projected greenhouse warming in irrigated regions. United States. doi:10.1029/2006GL026770.
Lobell, D, Bala, G, Bonfils, C, and Duffy, P. Thu . "Potential bias of model projected greenhouse warming in irrigated regions". United States. doi:10.1029/2006GL026770. https://www.osti.gov/servlets/purl/897972.
@article{osti_897972,
title = {Potential bias of model projected greenhouse warming in irrigated regions},
author = {Lobell, D and Bala, G and Bonfils, C and Duffy, P},
abstractNote = {Atmospheric general circulation models (GCMs) used to project climate responses to increased CO{sub 2} generally omit irrigation of agricultural land. Using the NCAR CAM3 GCM coupled to a slab-ocean model, we find that inclusion of an extreme irrigation scenario has a small effect on the simulated temperature and precipitation response to doubled CO{sub 2} in most regions, but reduced warming by as much as 1 C in some agricultural regions, such as Europe and India. This interaction between CO{sub 2} and irrigation occurs in cases where agriculture is a major fraction of the land surface and where, in the absence of irrigation, soil moisture declines are projected to provide a positive feedback to temperature change. The reduction of warming is less than 25% of the temperature increase modeled for doubled CO{sub 2} in most regions; thus greenhouse warming will still be dominant. However, the results indicate that land use interactions may be an important component of climate change uncertainty in some agricultural regions. While irrigated lands comprise only {approx}2% of the land surface, they contribute over 40% of global food production. Climate changes in these regions are therefore particularly important to society despite their relatively small contribution to average global climate.},
doi = {10.1029/2006GL026770},
journal = {Geophysical Research Letters, vol. 33, N/A, July 14, 2006, L13709, doi:10.1029/2006GL026770},
number = ,
volume = ,
place = {United States},
year = {Thu Apr 27 00:00:00 EDT 2006},
month = {Thu Apr 27 00:00:00 EDT 2006}
}