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Vegetation-climate feedbacks in a greenhouse world - discussion.

Wagner, A. and Woodward, F. I. and Mulligan, M. and Hewitt, CN (1998) Vegetation-climate feedbacks in a greenhouse world - discussion. Philosophical Transactions of the Royal Society of London Series B - Biological Sciences, 353 (1365). pp. 38-39. ISSN 0962-8436

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Abstract

The potential for feedbacks between terrestrial vegetation, climate, and the atmospheric CO2 partial pressure have been addressed by modelling. Previous research has established that under global warming and CO2 enrichment, the stomatal conductance of vegetation tends to decrease, causing a warming effect on top of the driving change in greenhouse warming. At the global scale, this positive feedback is ultimately changed to a negative feedback through changes in vegetation structure. In spatial terms this structural feedback has a variable geographical pattern in terms of magnitude and sign. At high latitudes, increases in vegetation leaf area index (LAI) and vegetation height cause a positive feedback, and warming through reductions in the winter snow-cover albedo. At lower latitudes when vegetation becomes more sparse with warming, the higher albedo of the underlying soil leads to cooling. However, the largest area effects are of negative feedbacks caused by increased evaporative cooling with increasing LAI. These effects do not include feedbacks on the atmospheric CO2 concentration, through changes in the carbon cycle of the vegetation. Modelling experiments, with biogeochemical, physiological and structural feedbacks on atmospheric CO2, but with no changes in precipitation, ocean activity or sea ice formation, have shown that a consequence of the CO2 fertilization effect on vegetation will be a reduction of atmospheric CO2 concentration, in the order of 12% by the year 2100 and a reduced global warming by 0.7°C, in a total greenhouse warming of 3.9°C.

Item Type: Article
Journal or Publication Title: Philosophical Transactions of the Royal Society of London Series B - Biological Sciences
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 21880
Deposited By: ep_ss_importer
Deposited On: 10 Feb 2009 15:23
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 15:53
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/21880

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