The Antarctic Ice Sheet lost about 3 trillion tonnes of ice between 1992 and 2017, according to an Analysis published in this week’s Nature. This figure corresponds to a mean sea-level rise of about 8 millimetres.
Antarctica’s ice sheets, which contain enough water to raise global sea level by 58 metres, are a key indicator of climate change and driver of sea-level rise. Understanding the current ice-sheet mass balance - the net balance of mass gains and losses - is key to estimating potential future changes in ice-sheet mass. More than 150 calculations of ice-mass loss from Antarctica have been made since 1989.
The Ice sheet Mass Balance Inter-comparison Exercise (IMBIE) team analysed 24 independent satellite-observation-based estimates of ice-sheet mass balance determined within the period 1992-2017, which they combined with modelling of the surface mass balance. They show that during this period, ocean-driven melting led to a tripling of ice-loss rates from West Antarctica, from 53 billion to 159 billion tonnes per year. The rate of ice loss from the Antarctic Peninsula increased from about 7 billion to 33 billion tonnes per year as a result of ice-shelf collapse. However, East Antarctica’s mass balance remains highly uncertain and is indistinguishable from zero. The authors note that further improvements to the assessment of ice-sheet mass balance are still possible - reassessing satellite measurements obtained in the 1990s could help, for example, and continued satellite observations remain essential.
The study is part of a special collection of articles in an Insight in this week’s Nature, which explores diverse aspects of Antarctica’s past, present and possible futures. The package brings together our current understanding of natural science in and around Antarctica, and uncovers our impacts on it.doi: 10.1038/s41586-018-0171-6 | Original article
doi: 10.1038/s41586-018-0182-3 | Original article
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