Ice sheets
Less Arctic sea ice both snows and melts Greenland
Open access · cc by · source: Europe PMC
Losing Arctic sea ice in a +2 °C world adds winter snow to Greenland but more than offsets it with extra summer melt.
Study at a glance
- Design
- Computational / modelling — Two 100-member CESM2 ensembles prescribing preindustrial vs +2 °C Arctic sea ice/SST
- N
- N=100 · 100 one-year ensemble members per ice state (April 2000–May 2001)
- Population
- Greenland Ice Sheet surface mass balance under prescribed Arctic sea-ice loss
- Outcome
- Winter snowfall gains vs larger summer melt response to Arctic sea-ice loss
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Arctic sea ice fell 19.0% in winter and 48.4% in summer (3.6 and 6.4 million km2). Winter SMB rose 23 ± 33 Gt year−1 from extra precipitation; summer SMB fell 33 ± 64 Gt year−1 as melt rose 36 ± 76 Gt year−1. Summer melt extent increased 3.5% and blocking days over Greenland rose about 25%.
Methodology
Two 100-member CESM2 ensembles (April 2000–May 2001) prescribed pre-industrial versus +2 °C Arctic sea-ice concentration and in-Arctic SSTs from CMIP5, then computed Greenland SMB from snowfall, melt, refreeze, and sublimation.
Limitations
One-year simulations cannot capture ice-dynamic discharge. Prescribed ice/SST omit full ocean coupling. Melt-response uncertainty (±64 Gt) is large. CESM2 overproduces liquid-containing Arctic clouds versus observations.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
Losing Arctic sea ice in a +2 °C world adds winter snow to Greenland but more than offsets it with extra summer melt.
Evidence for the claim as stated.
Emulators trained on one GCM can look excellent in one scenario and fail in another. The Greenland melt ANN’s SSP5-8.5 ensemble mean sits 1.6% from MAR, but SSP1-2.6 is 71.9% high; climate-sensitivity spread across CMIP6 dominates. Prescribed-ice CESM2 ensembles (Arctic sea ice −19.0% winter, −48.4% summer) are not downscaling at all: they are large-ensemble sensitivity experiments whose melt uncertainty (±64 Gt yr⁻¹ in summer SMB) dwarfs the winter snowfall gain (23±33 Gt yr⁻¹).
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
Emulators trained on one GCM can look excellent in one scenario and fail in another. The Greenland melt ANN’s SSP5-8.5 ensemble mean sits 1.6% from MAR, but SSP1-2.6 is 71.9% high; climate-sensitivity spread across CMIP6 dominates. Prescribed-ice CESM2 ensembles (Arctic sea ice −19.0% winter, −48.4% summer) are not downscaling at all: they are large-ensemble sensitivity experiments whose melt uncertainty (±64 Gt yr⁻¹ in summer SMB) dwarfs the winter snowfall gain (23±33 Gt yr⁻¹).
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