CMIP6 sea-level sensitivity lags observations
CMIP6/ISMIP6 transient sea-level sensitivity is ~30% below the historical “all but glaciers” rate, mainly because Antarctic ice-sheet models barely respond to warming.
Source
The Transient Sea Level Response to External Forcing in CMIP6 Models
Study at a glance
- Design
- Computational / modelling — Transient sea-level sensitivity from weighted CMIP6/ISMIP6 components vs AR6 historical rates
- N
- Multimodel CMIP6 and ice emulators; not a single sample N
- Population
- Global mean and component sea-level contributions under transient warming
- Outcome
- Model TSLS ~30% below historical all-but-glacier rate, mainly from weak Antarctic response
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
Authors computed transient sea-level sensitivity (TSLS: mm/yr per K of GMST) for steric, Greenland, West/East Antarctic, glacier, and GMSL pieces from weighted CMIP6 and ice emulators, then compared with AR6 historical budget rates.
What they found
Steric TSLS is 1.5±0.2 mm/yr/K (obs 1.4±0.5). Greenland is 0.8±0.2. EAIS is slightly negative (−0.1±0.2). Full GMSL TSLS is 5.3±1.0 mm/yr/K for 2016–2050 vs 3.0±0.4 after 2050. Historical all-but-glacier sensitivity (3.1±0.4) is ~30% above models; AIS observations are +0.4±0.2 vs near-zero modeled WAIS/EAIS dynamics.
The limits
What it doesn't show
TSLS is not equilibrium sea-level commitment after 2100. Glacier TSLS is non-stationary. Ice emulators inherit ISMIP6’s weak marine-ice dynamics and present-day zero-trend design.
Key terms
- TSLS
- Transient sea-level sensitivity: change in SLR rate per K of GMST.
- Steric sea level
- Ocean thermal expansion (and salinity) contribution.
- ISMIP6
- Ice Sheet Model Intercomparison Project used to force AR6 ice emulators.
- All but GIC
- Sea-level budget after removing glaciers and ice caps.
- GMST
- Global mean surface temperature used as the TSLS x-axis.
Flashcards
Research intelligence for this paper
See its role on concept claims, tensions it is part of, placement history, and related discoveries.
Quiz yourself
CMIP6 2051–2100 steric TSLS is about:
Common questions
Which component matches observations best?
Steric expansion, ~1.5 vs 1.4 mm/yr/K.
Where is the model–data gap?
Antarctic ice sheet, especially WAIS/Peninsula dynamics.
Does GMSL TSLS stay constant this century?
No: 5.3 mm/yr/K before 2050 vs 3.0 after, largely from shrinking glaciers.
How much 20th-century SLR do they tie to warming?
About 90%.
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