The Transient Sea Level response to external forcing in CMIP6 models

Abstract

 The rate of ice sheet mass loss and ocean expansion has a near linear relationship to global mean surface warming in both models and data.  The modeled transient sensitivity of the sea level budget to warming is compatible with historical behavior except for Antarctic mass loss.  Models of Antarctic mass loss may be biased as data shows increasing losses with warming in contrast to models.

Through an Ice Sheet, Darkly

“…Perhaps most intriguingly, Grinsted et al. (2022) find a significant discrepancy between models and observations, namely that observations show that sea‐level rates are more sensitive to surface‐temperature changes than the models anticipate.…”

“…Grinsted et al. (2022) hypothesize that mismatches between models and observations may arise from poor representation of ice flow and sliding on the West Antarctic ice sheet and the Antarctic Peninsula in models, which results in simulated ice discharge being too insensitive to temperature changes. Bamber et al.…”

“…(2022), Grinsted et al. (2022), and van de Wal et al. (2022), as well as the ocean, atmosphere, and solid Earth (Hamlington et al., 2021; Kopp et al., 2019).…”

“…Grinsted et al. (2022) constrain the transient sea‐level sensitivity to global warming using observations and models. Introduced by Grinsted and Christensen (2021) in analogy to the established notion of the transient climate response (Planton, 2013), this defines the change in the rate of global‐mean sea‐level rise with respect to changes in global‐mean surface temperature.…”

“…Grinsted et al. (2022) build on previous efforts by considering the most recent generation of climate, ice‐sheet, and glacier models, and by quantifying sensitivities of individual contributors to global sea level rise, including the ice sheets. The authors find that, for most contributors, sensitivities are nearly constant, meaning that rates of global‐mean sea‐level rise scale linearly with global‐mean surface temperatures.…”