TY - JOUR
T1 - Ice sheet contributions to future sea-level rise from structured expert judgment
AU - Bamber, Jonathan L.
AU - Oppenheimer, Michael
AU - Kopp, Robert E.
AU - Aspinall, Willy P.
AU - Cooke, Roger M.
N1 - Funding Information:
We thank the experts for their time and commitment. We thank the New York City Panel on Climate Change for contributing stakeholder input to planning this study, and members W. Solecki and V. Gornitz for reviewing the elicitation plan. We thank R. Westaway for help drafting figures and with the SI Appendix, and K. Rennert for assisting with documenting expert discussions. J.L.B. was supported by European Research Council Grant 694188 (GlobalMass) and a Royal Society Wolfson Merit award. R.M.C. was supported by NASA Grant NNX17AD55G. R.E.K. was supported in part by NSF Grant ICER-1663807 and NASA Grant 80NSSC17K0698. Support was also provided by the Rutgers University School of Arts and Sciences; The Princeton University Center for Policy Research on Energy and the Environment; the City of New York and its Department of Environmental Protection; and Resources for the Future.
Funding Information:
ACKNOWLEDGMENTS. We thank the experts for their time and commitment. We thank the New York City Panel on Climate Change for contributing stakeholder input to planning this study, and members W. Solecki and V. Gornitz for reviewing the elicitation plan. We thank R. Westaway for help drafting figures and with the SI Appendix, and K. Rennert for assisting with documenting expert discussions. J.L.B. was supported by European Research Council Grant 694188 (GlobalMass) and a Royal Society Wolfson Merit award. R.M.C. was supported by NASA Grant NNX17AD55G. R.E.K. was supported in part by NSF Grant ICER-1663807 and NASA Grant 80NSSC17K0698. Support was also provided by the Rutgers University School of Arts and Sciences; The Princeton University Center for Policy Research on Energy and the Environment; the City of New York and its Department of Environmental Protection; and Resources for the Future.
Publisher Copyright:
© 2019 National Academy of Sciences. All rights reserved.
PY - 2019
Y1 - 2019
N2 - Despite considerable advances in process understanding, numerical modeling, and the observational record of ice sheet contributions to global mean sea-level rise (SLR) since the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change, severe limitations remain in the predictive capability of ice sheet models. As a consequence, the potential contributions of ice sheets remain the largest source of uncertainty in projecting future SLR. Here, we report the findings of a structured expert judgement study, using unique techniques for modeling correlations between inter- and intra-ice sheet processes and their tail dependences. We find that since the AR5, expert uncertainty has grown, in particular because of uncertain ice dynamic effects. For a +2 °C temperature scenario consistent with the Paris Agreement, we obtain a median estimate of a 26 cm SLR contribution by 2100, with a 95th percentile value of 81 cm. For a +5 °C temperature scenario more consistent with unchecked emissions growth, the corresponding values are 51 and 178 cm, respectively. Inclusion of thermal expansion and glacier contributions results in a global total SLR estimate that exceeds 2 m at the 95th percentile. Our findings support the use of scenarios of 21st century global total SLR exceeding 2 m for planning purposes. Beyond 2100, uncertainty and projected SLR increase rapidly. The 95th percentile ice sheet contribution by 2200, for the +5 °C scenario, is 7.5 m as a result of instabilities coming into play in both West and East Antarctica. Introducing process correlations and tail dependences increases estimates by roughly 15%.
AB - Despite considerable advances in process understanding, numerical modeling, and the observational record of ice sheet contributions to global mean sea-level rise (SLR) since the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change, severe limitations remain in the predictive capability of ice sheet models. As a consequence, the potential contributions of ice sheets remain the largest source of uncertainty in projecting future SLR. Here, we report the findings of a structured expert judgement study, using unique techniques for modeling correlations between inter- and intra-ice sheet processes and their tail dependences. We find that since the AR5, expert uncertainty has grown, in particular because of uncertain ice dynamic effects. For a +2 °C temperature scenario consistent with the Paris Agreement, we obtain a median estimate of a 26 cm SLR contribution by 2100, with a 95th percentile value of 81 cm. For a +5 °C temperature scenario more consistent with unchecked emissions growth, the corresponding values are 51 and 178 cm, respectively. Inclusion of thermal expansion and glacier contributions results in a global total SLR estimate that exceeds 2 m at the 95th percentile. Our findings support the use of scenarios of 21st century global total SLR exceeding 2 m for planning purposes. Beyond 2100, uncertainty and projected SLR increase rapidly. The 95th percentile ice sheet contribution by 2200, for the +5 °C scenario, is 7.5 m as a result of instabilities coming into play in both West and East Antarctica. Introducing process correlations and tail dependences increases estimates by roughly 15%.
KW - Antarctica
KW - Climate predictions
KW - Greenland
KW - Ice sheets
KW - Sea-level rise
UR - http://www.scopus.com/inward/record.url?scp=85066795412&partnerID=8YFLogxK
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U2 - 10.1073/pnas.1817205116
DO - 10.1073/pnas.1817205116
M3 - Article
C2 - 31110015
AN - SCOPUS:85066795412
SN - 0027-8424
VL - 166
SP - 11195
EP - 11200
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 23
ER -