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| Titel |
Audit of the global carbon budget: estimate errors and their impact on uptake uncertainty |
| VerfasserIn |
A. P. Ballantyne, R. Andres, R. Houghton, B. D. Stocker, R. Wanninkhof, W. Anderegg, L. A. Cooper, M. DeGrandpre, P. P. Tans, J. B. Miller, C. Alden, J. W. C. White |
| 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 ; 12, no. 8 ; Nr. 12, no. 8 (2015-04-30), S.2565-2584 |
| Datensatznummer |
250117919
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| Publikation (Nr.) |
 copernicus.org/bg-12-2565-2015.pdf |
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| Zusammenfassung |
| Over the last 5 decades monitoring systems have been developed to detect
changes in the accumulation of carbon (C) in the atmosphere and ocean;
however, our ability to detect changes in the behavior of the global C cycle
is still hindered by measurement and estimate errors. Here we present a
rigorous and flexible framework for assessing the temporal and spatial
components of estimate errors and their impact on uncertainty in net C uptake
by the biosphere. We present a novel approach for incorporating temporally
correlated random error into the error structure of emission estimates. Based
on this approach, we conclude that the 2σ uncertainties of the
atmospheric growth rate have decreased from 1.2 Pg C yr−1 in the
1960s to 0.3 Pg C yr−1 in the 2000s due to an expansion of the
atmospheric observation network. The 2σ uncertainties in fossil fuel
emissions have increased from 0.3 Pg C yr−1 in the 1960s to almost
1.0 Pg C yr−1 during the 2000s due to differences in national
reporting errors and differences in energy inventories. Lastly, while land
use emissions have remained fairly constant, their errors still remain high
and thus their global C uptake uncertainty is not trivial. Currently, the
absolute errors in fossil fuel emissions rival the total emissions from land
use, highlighting the extent to which fossil fuels dominate the global C
budget. Because errors in the atmospheric growth rate have decreased faster
than errors in total emissions have increased, a ~20% reduction
in the overall uncertainty of net C global uptake has occurred. Given all
the major sources of error in the global C budget that we could identify, we
are 93% confident that terrestrial C uptake has increased and 97%
confident that ocean C uptake has increased over the last 5 decades. Thus, it
is clear that arguably one of the most vital ecosystem services currently
provided by the biosphere is the continued removal of approximately half of
atmospheric CO2 emissions from the atmosphere, although there are
certain environmental costs associated with this service, such as the
acidification of ocean waters. |
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