An expert judgement assessment of future sea level rise from the ice sheets

• Published in: Nature Climate Change
• Main Authors: Bamber, J. L., Aspinall, W. P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2013
• Subjects: CLIMATE-CHANGE; GLACIER; Ice Sheet
• Online Access: https://hdl.handle.net/1983/e9794fdb-ecd8-4c9e-8380-0d225e67ee46; https://research-information.bris.ac.uk/en/publications/e9794fdb-ecd8-4c9e-8380-0d225e67ee46; https://doi.org/10.1038/NCLIMATE1778

A major gap in predictive capability concerning the future evolution of the ice sheets was identified in the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change. As a consequence, it has been suggested that the AR4 estimates of future sea-level rise from this source may have been underestimated. Various approaches for addressing this problem have been tried, including semi-empirical models and conceptual studies. Here, we report a formalized pooling of expert views on uncertainties in future ice-sheet contributions using a structured elicitation approach.We find that the median estimate of such contributions is 29 cm—substantially larger than in the AR4—while the upper 95th percentile value is 84 cm, implying a conceivable risk of a sea-level rise of greater than a metre by 2100. On the critical question of whether recent ice-sheet behaviour is due to variability in the ice sheet–climate system or reflects a long-term trend, expert opinion is shown to be both very uncertain and undecided.