Scientists overlooking the edge of Mawson Glacier, East Antarctica (photograph: Richard Jones)
A review of current research has shown that drastically reducing greenhouse gas emissions could prevent the worst-case scenarios of sea-level rise.
The East Antarctic Ice Sheet holds most of the Earth’s glacier ice, which could cause a dramatic increase in sea level if it melts. However new research from Durham and Imperial College London has found that staying below the 2°C upper limit set by the Paris Agreement will help us restrict sea level rise to less than half a metre by the year 2500. If, on the other hand, warming continues to increase beyond the 2°C limit, we could potentially see the EAIS contribute several metres to sea-level rise in just a few centuries.
In the best-case scenario, with only a small rise in temperature the East Antarctic Ice Sheet (EAIS) might contribute only around two centimetres of sea level rise by 2100 - much less than the ice loss expected from Greenland and West Antarctica.
Co-author Professor Tina van de Flierdt from the Department of Earth Science and Engineering at Imperial said: “The future of the EAIS is very much within our control. Keeping global warming below 2°C, and ideally to 1.5°C, as the world’s nations agreed to in the 2015 Paris climate agreement, is what we need to aim for and act towards”.
The study is published in Nature.
Using the past to understand the future
To understand how the EAIS responds to global warming, we need to understand how it has responded to warm periods in the past. Previous work, led by students and postdoctoral researchers from Imperial, informed this review and examined the extent of ice loss from the EAIS during past warm periods. Understanding Antarctica’s geological past helps scientists to predict how ice will respond to global warming in the future.
To carry out the study, the researchers reviewed how the ice sheet responded to past warm periods, when carbon dioxide concentrations and atmospheric temperatures were only a little higher than they are today. Even as recently as 400,000 years ago, not that long ago on geological timescales, there is evidence that a part of the EAIS retreated 700 km inland in response to only 1-2°C of global warming.
Professor van de Flierdt, who studies the palaeoclimate of the EAIS, said: “This review shines a light on this massive ice sheet. While we used to think it was much less vulnerable to climate change compared to its smaller West Antarctic neighbour or Greenland, we now know that this might not be true.
This review confirms future sea-level rise scenarios. We know that the ice sheets in this area have previously caused sea-level rise. Now, we have a better understanding of the limits to global temperature increase) required to mitigate sea level rise.
Lead author Professor Chris Stokes, of the Department of Geography, Durham University, UK, said: “A key conclusion from our analysis is that the fate of the East Antarctic Ice Sheet remains very much in our hands. This ice sheet is by far the largest on the planet, containing the equivalent of 52 metres of sea level and it’s really important that we do not awaken this sleeping giant.”
The research was led by Durham University working with King’s College London, and Imperial College London (UK); the Australian National University, University of New South Wales, University of Tasmania and Monash University (Australia); Université Grenoble Alpes (France); the University of Colorado Boulder, NASA Goddard Space Flight Center and Columbia University (USA).
It was funded by the: UK Natural Environment Research Council; the Australian Research Council Special Research Initiatives in the Australian Centre for Excellence in Antarctic Science, and Securing Antarctica’s Environmental Future; the Centre for Southern Hemisphere Oceans Research; the Australian Antarctic Program Partnership; the European Union’s Horizon 2020 research and innovation programme; and the National Aeronautics and Space Administration.
Reference: Stokes, C.R., Abram, N.J., Bentley, M.J. et al. Response of the East Antarctic Ice Sheet to past and future climate change. Nature 608, 275–286 (2022). https://doi.org/10.1038/s41586-022-04946-0
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