Projected Land Ice Contributions to 21st-Century Sea Level Rise
Multiple glacier models, ice sheet models, climate models, and emissions scenarios were used to simulated the impact of land ice (glaciers and ice sheets) evolution on future sea-level rise. These multi-model ensembles were combined via statistical emulation to build probabilistic projections of future sea-level rise from all sources of land ice. DOE contributed to the work at multiple levels including the selecting of appropriate climate models (HiLAT), developing model parameterizations (ProSPect), and conducting high-fidelity, high-resolution ice sheet model simulations using the MALI and BISICLES ice sheet models (ProSPect).
This work applied significantly improved models and methods to provide comprehensive and up-to-date projections of sea-level rise from land ice evolution. Results from the study confirm that Antarctica remains a critical focus for reducing future uncertainty in sea-level rise. By limiting global warming to 1.5 degrees C above pre-industrial temperatures, the 21st-century contribution to sea-level rise land ice can be reduced from 25 to 13 cm.
The land ice contribution to global mean sea-level rise has not yet been projected using the most recent set of glacier, ice sheet, and climate models, combined with the latest set of greenhouse gas emissions scenarios. This work uses statistical emulation of glacier, ice sheet, and climate model simulations in order to estimate probability distributions for the future sea-level rise from all sources of land ice. By limiting global warming to 1.5 degrees Celsius, the land ice contribution to twenty-first-century sea-level rise can be halved relative to current emissions pledges (13 cm of sea-level equivalent versus 25 cm). The projected contribution from Antarctica remains highly uncertain; under pessimistic assumptions, the median land ice contribution increases from 25 to 42 centimeters sea-level equivalent for current emissions pledges.