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Sensitivity of terrestrial water and energy budgets to CO(2)-physiological forcing: an investigation using an offline land model

Gopalakrishnan, Ranjith and Bala, Govindsamy and Jayaraman, Mathangi and Cao, Long and Nemani, Ramakrishna and Ravindranath, NH (2011) Sensitivity of terrestrial water and energy budgets to CO(2)-physiological forcing: an investigation using an offline land model. In: Environmental Research Letters, 6 (4).

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Official URL: http://iopscience.iop.org/1748-9326/6/4/044013/


Increasing concentrations of atmospheric carbon dioxide (CO(2)) influence climate by suppressing canopy transpiration in addition to its well- known greenhouse gas effect. The decrease in plant transpiration is due to changes in plant physiology (reduced opening of plant stomata). Here, we quantify such changes in water flux for various levels of CO(2) concentrations using the National Center for Atmospheric Research's (NCAR) Community Land Model. We find that photosynthesis saturates after 800 ppmv (parts per million, by volume) in this model. However, unlike photosynthesis, canopy transpiration continues to decline at about 5.1% per 100 ppmv increase in CO(2) levels. We also find that the associated reduction in latent heat flux is primarily compensated by increased sensible heat flux. The continued decline in canopy transpiration and subsequent increase in sensible heat flux at elevated CO(2) levels implies that incremental warming associated with the physiological effect of CO(2) will not abate at higher CO(2) concentrations, indicating important consequences for the global water and carbon cycles from anthropogenic CO(2) emissions.

Item Type: Journal Article
Publication: Environmental Research Letters
Publisher: IOP Publishing ltd
Additional Information: Copyright of this article belongs to IOP Publishing ltd.
Keywords: CO(2)-physiological effect;CO(2)-fertilization;canopy transpiration;water cycle;runoff;climate change
Department/Centre: Division of Mechanical Sciences > Divecha Centre for Climate Change
Division of Mechanical Sciences > Centre for Sustainable Technologies (formerly ASTRA)
Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences
Date Deposited: 17 Feb 2012 11:54
Last Modified: 17 Feb 2012 11:54
URI: http://eprints.iisc.ac.in/id/eprint/43544

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