Introduction

This chapter focuses on the coupling of glacier and climate models for simulation of glacier and icefield response to climate change. Sections 32.2 and 32.3 summarize glacier mass balance and ice dynamics considerations, concentrating on concepts that are central to understanding of global-scale glacier and ice-sheet evolution. Sections 32.4 and 32.5 discuss the coupling of climate and glaciological models, along with some of the important limitations and uncertainties in glacier-climate forecasts. The discussion in this review is necessarily selective, with a focus on the current state-of-the-art in glacier-climate modelling. For a more comprehensive examination of glacier-climate interactions, mass balance modelling, and the response of glaciers and ice sheets to climate change, interested readers are referred to the excellent texts of Oerlemans (1989,2001) and Paterson (1994). Chapters in this volume by Braithwaite, Haeberli, Reeh, Vaughan and Huybrechts also expand on these topics.

I give a broad treatment of continental ice masses, from alpine glaciers through to continental-scale ice sheets in Greenland and Antarctica. Although these ice masses have different climate-change response times and mass balance regimes, the same basic processes govern their behaviour and their expected response to ongoing climate change. Because ice masses in Greenland and Antarctica represent almost 97% of the glaciated area and an estimated 99.8% of ice volume in the world (Ohmura et al., 1996), the impact of climate change on glacier mass balance in Greenland and Antarctica is of primary importance for sea-level change. Intermediate-scale icefields and ice caps, such as those in Patagonia, Iceland, Alaska and the Arctic, also present an interesting case. These ice masses are small enough to be significantly impacted by decade- and century-scale climate change, but are large enough to be important to eustatic sea level (Arendt et al., 2002; Meier et al., 2003). In addition to questions of global sea level, changing glacial environments in the 21st century are also expected to produce significant climate feed-backs in all of the world's glaci-erized regions.

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