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| Titel |
Emergence of multiple ocean ecosystem drivers in a large ensemble suite with an Earth system model |
| VerfasserIn |
K. B. Rodgers, J. Lin, T. L. Frölicher |
| 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. 11 ; Nr. 12, no. 11 (2015-06-03), S.3301-3320 |
| Datensatznummer |
250117963
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| Publikation (Nr.) |
 copernicus.org/bg-12-3301-2015.pdf |
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| Zusammenfassung |
| Marine ecosystems are increasingly stressed by human-induced changes. Marine
ecosystem drivers that contribute to stressing ecosystems – including
warming, acidification, deoxygenation and perturbations to biological
productivity – can co-occur in space and time, but detecting their trends is
complicated by the presence of noise associated with natural variability in
the climate system. Here we use large initial-condition ensemble simulations
with an Earth system model under a historical/RCP8.5 (representative
concentration pathway 8.5) scenario over 1950–2100 to consider emergence
characteristics for the four individual and combined drivers. Using a
1-standard-deviation (67% confidence) threshold of signal to noise to
define emergence with a 30-year trend window, we show that ocean
acidification emerges much earlier than other drivers, namely during the
20th century over most of the global ocean. For biological productivity, the
anthropogenic signal does not emerge from the noise over most of the global
ocean before the end of the 21st century. The early emergence pattern for sea
surface temperature in low latitudes is reversed from that of subsurface
oxygen inventories, where emergence occurs earlier in the Southern Ocean. For
the combined multiple-driver field, 41% of the global ocean exhibits
emergence for the 2005–2014 period, and 63% for the 2075–2084 period.
The combined multiple-driver field reveals emergence patterns by the end of
this century that are relatively high over much of the Southern Ocean, North
Pacific, and Atlantic, but relatively low over the tropics and the South
Pacific. For the case of two drivers, the tropics including habitats of coral
reefs emerges earliest, with this driven by the joint effects of
acidification and warming. It is precisely in the regions with pronounced
emergence characteristics where marine ecosystems may be expected to be
pushed outside of their comfort zone determined by the degree of natural
background variability to which they are adapted. The results underscore the
importance of sustained multi-decadal observing systems for monitoring
multiple ecosystems drivers. |
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