Multi-Model Analyses Reveals the Regional Contribution of Mountain Glaciers and Ice Caps to Future Sea-level Rise

Scientists believe that mountains glaciers and ice caps have been a major contributor to the rise in global sea-levels over the past decades. In this paper, Radić & Hock (2011) investigate the Intergovernmental Panel for Climate Change’s (IPCC) projections for the global sea-level rise in the twenty first century, and they conclude that these estimates are not wholly accurate as they do not account for the effects of precipitation and the regional factors influencing the rise in sea-levels. The authors projected the changes in volume of all the ice caps and glaciers on Earth in response to twenty first century temperature and precipitation projections from ten global climate change models (GCMs) reported by the IPCC. They conclude that glaciers in Arctic Canada, Alaska and Antarctica would be largest contributors to the rise in global sea-levels in 2100. Thus, there will be a significant reduction in total glacier volume by 2100, and some mountainous regions may even lose up to 75% of their present ice volume. – Sachi Singh
Radić, V., Hock, R. 2011. Regionally differentiated contribution of mountain glaciers and ice caps to future sea-level rise. Nature Geoscience. doi:10.1038/ngeo1052.

The Fourth Assessment Report of the IPCC predicts that the wastage of glaciers and ice caps will lead to a 0.07 to 0.17 m rise in global sea-levels in the twenty first century. Another study found the accelerating rates of mass loss from the glacier mass balance data between 1995 and 2005; the authors of this study used this model to predict a 0.240±0.128m rise in sea levels, assuming this rate of acceleration is constant. In order to resolve these discrepancies, Radić & Hock studied the volume changes of mountain glaciers and ice caps in 19 spatially resolved glacierized regions. To quantify future volume changes, the authors developed a calibrated mass balance model to applied it to all the glaciers available in the World Glacier Inventory (WGI-XF). According to their multi-model means, glaciers around the world will cause a 0.124±0.037m rise in sea-level by 2100. Assuming the GCMs are accurate, the authors predict that there will be a global ice volume loss of 0.124±0.037m SLE (sea level equivalents) by 2100. The volume loss varies considerably from region to region; the smallest loss was predicted to be in Greenland and High Mountain Asia, and the largest in the European Alps and New Zealand. However, these places are not significant contributors to the future rise in sea-level. The glaciers in Arctic Canada, Alaska and Antarctica are estimated to be the largest contributers to the rise in sea-levels. While there are some uncertainties associated with the rise initial setup of the model, this study reveals  the main regional contributers to sea-level rise and pinpoint the areas that are most vulnerable to glacier waste. Thus, if warming continues as expected, glaciers will be a large contributer to sea-level rise around the world. 

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