Greenland plays a large role in the gloomy picture painted of probable future sea-level rise

Goelzer et al (2012) paint a portentous picture of what is likely to happen to the global sea-level over the next 1000 years. This worrying assessment is based on our current best understanding of how the world’s giant ice sheets of Greenland and Antarctica, as well as a quarter of a million smaller...

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Bibliographic Details
Published in:Environmental Research Letters
Main Author: Edward Hanna
Format: Article in Journal/Newspaper
Language:English
Published: IOP Publishing 2012
Subjects:
Q
Online Access:https://doi.org/10.1088/1748-9326/7/4/041002
https://doaj.org/article/861f6bd61d5949d48977c11d022e4630
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Summary:Goelzer et al (2012) paint a portentous picture of what is likely to happen to the global sea-level over the next 1000 years. This worrying assessment is based on our current best understanding of how the world’s giant ice sheets of Greenland and Antarctica, as well as a quarter of a million smaller glacial ice masses, and the ocean collectively respond to ongoing climate change. Theirs is a state of the science study that integrates these key contributors of sea-level change based on the latest models and current understanding, and an integrated Earth systems modelling approach termed LOVECLIM. As they point out in their study, only a handful of global climate models to date—i.e. models that are used to make predictions of future climate change—incorporate dynamically (fully) coupled ice-sheet models. According to the scenarios presented by Goelzer et al (2012), we could see between 2.1 and 6.8 m of global sea-level rise by 3000 AD, compared with ‘just’ 1.1 m if the atmosphere is stabilised at 2000 CO _2 levels. Much, up to some 4 m, of this contribution comes from increased melting and mass loss of the Greenland ice sheet, which is several times more sensitive than the Antarctic ice sheet to warming temperatures in these simulations. Interestingly, dynamical ice mass losses through iceberg calving become increasingly less significant for Greenland as the ice sheet retreats further inland during the 1000 yr runs (Sole et al 2008). The latest modelling studies show that around a half, perhaps more, of the recent Greenland mass losses (Barletta et al 2012, Rignot et al 2011) are already through increased melt and runoff (Hanna et al 2008, 2012, van den Broeke et al 2009); note also the recent (summer 2012) record surface melting of the Greenland ice sheet (Nghiem et al 2012) caused by atmospheric forcing (Overland et al 2012) and the potential of such events to impact on ice flow (Bartholomew et al 2011). By contrast, the greatest sea-level rise reported for Antarctica by 3000 AD is no more than 94 cm; Antarctica ...