Ice Sheets, Glaciers, and Sea Level

• Main Authors: Allison, I, Colgan, W, King, M, Paul, F
• Format: Book Part
• Language: English
• Published: Elsevier 2015
• Subjects: Earth Sciences; Physical Geography and Environmental Geoscience; Natural Hazards; Greenland; Antarc*; Antarctica
• Online Access: https://doi.org/10.1016/B978-0-12-394849-6.00020-2; http://ecite.utas.edu.au/100517

Within the past 125,000 years, variations in Earths climate have resulted in global sealevels fluctuating from 130 to 140 m lower than present day to 6 to 9 m higher.Presently, global mean sea level is rising at its fastest rate in the past 6,000 years(~3 mm/year). In this chapter, we discuss both the causes and implications of sea-levelrise from the perspective of a cryospheric hazard. We also survey the best estimates ofsea-level rise and cryospheric mass change from a variety of monitoring techniques.The transfer of terrestrial ice into the sea has contributed about 50 percent of the sea-levelrise since 1993, and probably exceeded the combined sea-level changes due tothermal expansion, changes in terrestrial water storage, and changes in ocean basin sizesince 2003. This cryospheric contribution to sea-level rise is approximately equallysplit between the combined ice sheets of Greenland and Antarctica, and the globalpopulation of about 200,000 glaciers. The societal effects of sea-level rise will behighly varied throughout the world, with some locations experiencing relative sea-leveldrop, whereas others experience a relative sea-level rise several times the global mean.Perhaps counter-intuitively, the sea-level rise due to terrestrial ice loss will be mostsubstantial in areas furthest from the source of melting ice. Although this cryospherichazard will unfold over a much longer time scale than many of the other hazardsdiscussed in this volume, the ramifications of sea-level rise will likely be more widespreadand profound. Some implications discussed here include coastal inundation,increased coastal flood frequency and groundwater salinization.