 |
| Titel |
Projecting Antarctic ice discharge using response functions from SeaRISE ice-sheet models |
| VerfasserIn |
A. Levermann, R. Winkelmann, S. Nowicki, J. L. Fastook, K. Frieler, R. Greve, H. H. Hellmer, M. A. Martin, M. Meinshausen, M. Mengel, A. J. Payne, D. Pollard, T. Sato, R. Timmermann, W. L. Wang, R. A. Bindschadler |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
2190-4979
|
| Digitales Dokument |
URL |
| Erschienen |
In: Earth System Dynamics ; 5, no. 2 ; Nr. 5, no. 2 (2014-08-14), S.271-293 |
| Datensatznummer |
250115365
|
| Publikation (Nr.) |
 copernicus.org/esd-5-271-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| The largest uncertainty in projections of future sea-level change results
from the potentially changing dynamical ice discharge from Antarctica. Basal
ice-shelf melting induced by a warming ocean has been identified as a major
cause for additional ice flow across the grounding line. Here we attempt to
estimate the uncertainty range of future ice discharge from Antarctica by
combining uncertainty in the climatic forcing, the oceanic response and the
ice-sheet model response. The uncertainty in the global mean temperature
increase is obtained from historically constrained emulations with the
MAGICC-6.0 (Model for the Assessment of Greenhouse gas Induced Climate Change) model. The oceanic forcing is derived from scaling of the
subsurface with the atmospheric warming from 19 comprehensive climate models
of the Coupled Model Intercomparison Project (CMIP-5) and two ocean models
from the EU-project Ice2Sea. The dynamic ice-sheet response is derived
from linear response functions for basal ice-shelf melting for four different
Antarctic drainage regions using experiments from the Sea-level Response to
Ice Sheet Evolution (SeaRISE) intercomparison project with five different
Antarctic ice-sheet models.
The resulting uncertainty range for the historic Antarctic contribution to
global sea-level rise from 1992 to 2011 agrees with the observed
contribution for this period if we use the three ice-sheet models with an
explicit representation of ice-shelf dynamics and account for the
time-delayed warming of the oceanic subsurface compared to the surface air
temperature. The median of the additional ice loss for the 21st century
is computed to 0.07 m (66% range: 0.02–0.14 m; 90% range: 0.0–0.23 m)
of global sea-level equivalent for the low-emission RCP-2.6 (Representative Concentration Pathway) scenario and
0.09 m (66% range: 0.04–0.21 m; 90% range: 0.01–0.37 m) for the
strongest RCP-8.5. Assuming no time delay between the atmospheric warming
and the oceanic subsurface, these values increase to 0.09 m (66% range:
0.04–0.17 m; 90% range: 0.02–0.25 m) for RCP-2.6 and 0.15 m (66% range:
0.07–0.28 m; 90% range: 0.04–0.43 m) for RCP-8.5.
All probability distributions are highly skewed towards high values. The
applied ice-sheet models are coarse resolution with limitations in the
representation of grounding-line motion. Within the constraints of the
applied methods, the uncertainty induced from different ice-sheet models is
smaller than that induced by the external forcing to the ice sheets. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|