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| Titel |
Abrupt change in climate and climate models |
| VerfasserIn |
A. J. Pitman, R. J. Stouffer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 10, no. 6 ; Nr. 10, no. 6 (2006-11-28), S.903-912 |
| Datensatznummer |
250008291
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| Publikation (Nr.) |
 copernicus.org/hess-10-903-2006.pdf |
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| Zusammenfassung |
| First, we review the evidence that abrupt climate changes have occurred in
the past and then demonstrate that climate models have developing capacity
to simulate many of these changes. In particular, the processes by which
changes in the ocean circulation drive abrupt changes appear to be captured
by climate models to a degree that is encouraging. The evidence that past
changes in the ocean have driven abrupt change in terrestrial systems is
also convincing, but these processes are only just beginning to be included
in climate models. Second, we explore the likelihood that climate models can
capture those abrupt changes in climate that may occur in the future due to
the enhanced greenhouse effect. We note that existing evidence indicates
that a major collapse of the thermohaline circulation seems unlikely in the
21st century, although very recent evidence suggests that a weakening
may already be underway. We have confidence that current climate models can
capture a weakening, but a collapse in the 21st century of the thermohaline
circulation is not projected by climate models. Worrying evidence of
instability in terrestrial carbon, from observations and modelling studies,
is beginning to accumulate. Current climate models used by the
Intergovernmental Panel on Climate Change for the 4th Assessment Report
do not include these terrestrial carbon processes. We therefore can not make
statements with any confidence regarding these changes. At present, the
scale of the terrestrial carbon feedback is believed to be small enough that
it does not significantly affect projections of warming during the first
half of the 21st century. However, the uncertainties in how biological
systems will respond to warming are sufficiently large to undermine
confidence in this belief and point us to areas requiring significant
additional work. |
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