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| Titel |
Role of vegetation change in future climate under the A1B scenario and a climate stabilisation scenario, using the HadCM3C Earth system model |
| VerfasserIn |
P. D. Falloon, R. Dankers, R. A. Betts, C. D. Jones, B. B. B. Booth, F. H. Lambert |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 11 ; Nr. 9, no. 11 (2012-11-23), S.4739-4756 |
| Datensatznummer |
250007408
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| Publikation (Nr.) |
 copernicus.org/bg-9-4739-2012.pdf |
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| Zusammenfassung |
The aim of our study was to use the coupled climate-carbon cycle model
HadCM3C to quantify climate impact of ecosystem changes over recent decades
and under future scenarios, due to changes in both atmospheric CO2 and
surface albedo. We use two future scenarios – the IPCC SRES A1B scenario,
and a climate stabilisation scenario (2C20), allowing us to assess the
impact of climate mitigation on results. We performed a pair of simulations
under each scenario – one in which vegetation was fixed at the initial
state and one in which vegetation changes dynamically in response to climate
change, as determined by the interactive vegetation model within HadCM3C.
In our simulations with interactive vegetation, relatively small changes in
global vegetation coverage were found, mainly dominated by increases in shrub
and needleleaf trees at high latitudes and losses of broadleaf trees and
grasses across the Amazon. Globally this led to a loss of terrestrial carbon,
mainly from the soil. Global changes in carbon storage were related to the
regional losses from the Amazon and gains at high latitude. Regional
differences in carbon storage between the two scenarios were largely driven
by the balance between warming-enhanced decomposition and altered vegetation
growth. Globally, interactive vegetation reduced albedo acting to enhance
albedo changes due to climate change. This was mainly related to the darker
land surface over high latitudes (due to vegetation expansion, particularly
during December–January and March–May); small increases in albedo occurred
over the Amazon. As a result, there was a relatively small impact of
vegetation change on most global annual mean climate variables, which was
generally greater under A1B than 2C20, with markedly stronger
local-to-regional and seasonal impacts. Globally, vegetation change amplified
future annual temperature increases by 0.24 and 0.15 K (under A1B and 2C20,
respectively) and increased global precipitation, with reductions in
precipitation over the Amazon and increases over high latitudes. In general,
changes were stronger over land – for example, global temperature changes
due to interactive vegetation of 0.43 and 0.28 K under A1B and 2C20,
respectively. Regionally, the warming influence of future vegetation change
in our simulations was driven by the balance between driving factors. For
instance, reduced tree cover over the Amazon reduced evaporation
(particularly during June–August), outweighing the cooling influence of any
small albedo changes. In contrast, at high latitudes the warming impact of
reduced albedo (particularly during December–February and March–May) due to
increased vegetation cover appears to have offset any cooling due to small
evaporation increases.
Climate mitigation generally reduced the impact of vegetation change on
future global and regional climate in our simulations. Our study therefore
suggests that there is a need to consider both biogeochemical and
biophysical effects in climate adaptation and mitigation decision making. |
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