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Title: CLMcrop yields and water requirements: avoided impacts by choosing RCP 4.5 over 8.5

Here, we perform CLMcrop simulations of the 20th and 21st centuries to assess potential avoided impacts in (a) crop yield losses and (b) water demand increases if humanity were to choose the representative concentration pathway (RCP) 4.5 instead of 8.5. RCP 8.5 imposes more extreme climatic changes on CLMcrop, while simultaneously exposing the crops to higher CO2 fertilization than RCP 4.5. As a result CLMcrop simulates global to regional scale changes in yield and water requirements for RCP 8.5 that exceed and sometimes more than double the RCP 4.5 changes relative to today. Under RCP 4.5 then, human societies may confront easier adaptation to changes in crop yields and water requirements. Under both RCPs, CLMcrop projects declining global yields for C3 crops (e.g., wheat, soybean, rice) without CO 2 fertilization and C4 crops (corn, sugarcane) without irrigation. Yield declines of 3 t ha -1 stand out in parts of tropical and subtropical Africa and South America (presently areas of rapid agricultural expansion) and are due to increasing plant respiration and decreasing soil moisture, both due to rising temperatures. Irrigation and CO 2 fertilization mitigate yield losses and in some cases lead to gains, so irrigation may help maintain or increasemore » current yields through the 21st century. However, simulated global irrigation requirements increase: as much as 23 % for C4 crops without CO 2 fertilization under RCP 8.5 and as little as 3 % for C4 crops with CO 2 fertilization under RCP4.5. Nitrogen fertilized crops display greater vulnerability to climate and environmental change than unfertilized crops in our simulations; still relative to unfertilized crops, they deliver significantly higher yields and remain indispensable in supporting a more populous and affluent humanity. These CLMcrop results broadly agree with previously published outcomes for the 21st century. We describe in this article a new version of CLMcrop that represents prognostic crop behavior not only in the mid-latitudes but also the tropics.« less
Authors:
ORCiD logo [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. National Center for Atmospheric Research, Boulder, CO (United States); Climate Corporation, San Francisco, CA (United States)
  2. Cooperative Institute for Research in Environmental Sciences, Boulder, CO (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
  4. Univ. of Colorado, Boulder, CO (United States). Inst. of Arctic and Alpine Research
  5. National Center for Atmospheric Research, Boulder, CO (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Climatic Change
Additional Journal Information:
Journal Volume: 146; Journal Issue: 3-4; Journal ID: ISSN 0165-0009
Publisher:
Springer
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES
OSTI Identifier:
1465138

Levis, Samuel, Badger, Andrew, Drewniak, Beth, Nevison, Cynthia, and Ren, Xiaolin. CLMcrop yields and water requirements: avoided impacts by choosing RCP 4.5 over 8.5. United States: N. p., Web. doi:10.1007/s10584-016-1654-9.
Levis, Samuel, Badger, Andrew, Drewniak, Beth, Nevison, Cynthia, & Ren, Xiaolin. CLMcrop yields and water requirements: avoided impacts by choosing RCP 4.5 over 8.5. United States. doi:10.1007/s10584-016-1654-9.
Levis, Samuel, Badger, Andrew, Drewniak, Beth, Nevison, Cynthia, and Ren, Xiaolin. 2016. "CLMcrop yields and water requirements: avoided impacts by choosing RCP 4.5 over 8.5". United States. doi:10.1007/s10584-016-1654-9. https://www.osti.gov/servlets/purl/1465138.
@article{osti_1465138,
title = {CLMcrop yields and water requirements: avoided impacts by choosing RCP 4.5 over 8.5},
author = {Levis, Samuel and Badger, Andrew and Drewniak, Beth and Nevison, Cynthia and Ren, Xiaolin},
abstractNote = {Here, we perform CLMcrop simulations of the 20th and 21st centuries to assess potential avoided impacts in (a) crop yield losses and (b) water demand increases if humanity were to choose the representative concentration pathway (RCP) 4.5 instead of 8.5. RCP 8.5 imposes more extreme climatic changes on CLMcrop, while simultaneously exposing the crops to higher CO2 fertilization than RCP 4.5. As a result CLMcrop simulates global to regional scale changes in yield and water requirements for RCP 8.5 that exceed and sometimes more than double the RCP 4.5 changes relative to today. Under RCP 4.5 then, human societies may confront easier adaptation to changes in crop yields and water requirements. Under both RCPs, CLMcrop projects declining global yields for C3 crops (e.g., wheat, soybean, rice) without CO2 fertilization and C4 crops (corn, sugarcane) without irrigation. Yield declines of 3 t ha-1 stand out in parts of tropical and subtropical Africa and South America (presently areas of rapid agricultural expansion) and are due to increasing plant respiration and decreasing soil moisture, both due to rising temperatures. Irrigation and CO2 fertilization mitigate yield losses and in some cases lead to gains, so irrigation may help maintain or increase current yields through the 21st century. However, simulated global irrigation requirements increase: as much as 23 % for C4 crops without CO2 fertilization under RCP 8.5 and as little as 3 % for C4 crops with CO2 fertilization under RCP4.5. Nitrogen fertilized crops display greater vulnerability to climate and environmental change than unfertilized crops in our simulations; still relative to unfertilized crops, they deliver significantly higher yields and remain indispensable in supporting a more populous and affluent humanity. These CLMcrop results broadly agree with previously published outcomes for the 21st century. We describe in this article a new version of CLMcrop that represents prognostic crop behavior not only in the mid-latitudes but also the tropics.},
doi = {10.1007/s10584-016-1654-9},
journal = {Climatic Change},
number = 3-4,
volume = 146,
place = {United States},
year = {2016},
month = {3}
}