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| Titel |
Impact of rapid sea-ice reduction in the Arctic Ocean on the rate of ocean acidification |
| VerfasserIn |
A. Yamamoto, M. Kawamiya, A. Ishida, Y. Yamanaka, S. Watanabe |
| 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. 6 ; Nr. 9, no. 6 (2012-06-29), S.2365-2375 |
| Datensatznummer |
250007137
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| Publikation (Nr.) |
 copernicus.org/bg-9-2365-2012.pdf |
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| Zusammenfassung |
| The largest pH decline and widespread undersaturation with respect to
aragonite in this century due to uptake of anthropogenic carbon dioxide in
the Arctic Ocean have been projected. The reductions in pH and aragonite
saturation state in the Arctic Ocean have been caused by the melting of sea
ice as well as by an increase in the concentration of atmospheric carbon
dioxide. Therefore, future projections of pH and aragonite saturation in the
Arctic Ocean will be affected by how rapidly the reduction in sea ice
occurs. The observed recent Arctic sea-ice loss has been more rapid than
projected by many of the climate models that contributed to the
Intergovernmental Panel on Climate Change Fourth Assessment Report. In this
study, the impact of sea-ice reduction rate on projected pH and aragonite
saturation state in the Arctic surface waters was investigated. Reductions
in pH and aragonite saturation were calculated from the outputs of two
versions of an Earth system model with different sea-ice reduction rates
under similar CO2 emission scenarios. The newer model version projects
that Arctic summer ice-free condition will be achieved by the year 2040, and
the older version predicts ice-free condition by 2090. The Arctic surface
water was projected to be undersaturated with respect to aragonite in the
annual mean when atmospheric CO2 concentration reaches 513 (606) ppm in
year 2046 (2056) in new (old) version. At an atmospheric CO2
concentration of 520 ppm, the maximum differences in pH and aragonite
saturation state between the two versions were 0.1 and 0.21 respectively.
The analysis showed that the decreases in pH and aragonite saturation state
due to rapid sea-ice reduction were caused by increases in both CO2
uptake and freshwater input. Thus, the reductions in pH and aragonite
saturation state in the Arctic surface waters are significantly affected by
the difference in future projections for sea-ice reduction rate. Our results
suggest that the future reductions in pH and aragonite saturation state
could be significantly faster than previously projected if the sea-ice
reduction in the Arctic Ocean keeps its present pace. |
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