Moving beyond ice loss scenarios for Antarctica
Abstract
Scenario-based projections of individual components of sea level change are difficult to reconcile with probability distributions for sea level at the global and/or local scale. It is also difficult to assess the origin of key subjective decisions in the construction of these scenarios. An example is the historical distinction between the sensitivity of the East and West Antarctic Ice Sheets to climatic forcing. Observations show that this distinction may not have a well-defined physical basis at smaller scales. Recent “kinematic” approaches impose increases in ice discharge at the scale of individual outlet glaciers, yet the criteria for inclusion in these scenarios are unclear and differ between studies. Projections of the response of sub-regions of ice sheets to climate forcing should be informed by key physical characteristics, which may include ocean and/or atmospheric boundary conditions, bedrock and embayment morphology, and the stress regime of the grounded ice. Here, we assess: 1) the volume of Antarctic ice that is included in ice loss scenarios under different plausible sets of assumptions, and 2) the impact of these assumptions on the Antarctic contribution to sea level change. In the short term, this approach may raise or lower upper bounds proposed by earlier studies, depending on the criteria and rates employed. Perhaps more importantly, it is a step towards a fully probabilistic methodology, informing the requirements for models that may be used in probabilistic projections. Updating is possible: key sources of uncertainty may be revisited as more is learned about future climate forcing and rate-limiting processes in ice sheets.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMNH21C1408L
- Keywords:
-
- 0726 CRYOSPHERE / Ice sheets;
- 0762 CRYOSPHERE / Mass balance;
- 1641 GLOBAL CHANGE / Sea level change;
- 6309 POLICY SCIENCES / Decision making under uncertainty