Rapid postglacial rebound amplifies global sea level rise following West Antarctic Ice Sheet collapse.

Geodetic, seismic, and geological evidence indicates that West Antarctica is underlain by low-viscosity shallow mantle. Thus, as marine-based sectors of the West Antarctic Ice Sheet (WAIS) retreated during past interglacials, or will retreat in the future, exposed bedrock will rebound rapidly and flux meltwater out into the open ocean. Previous studies have suggested that this contribution to global mean sea level (GMSL) rise is small and occurs slowly.

Weak tides during Cryogenian glaciations.

The severe "Snowball Earth" glaciations proposed to have existed during the Cryogenian period (720 to 635 million years ago) coincided with the breakup of one supercontinent and assembly of another. Whereas the presence of extensive continental ice sheets predicts a tidally energetic Snowball ocean due to the reduced ocean depth, the supercontinent palaeogeography predicts weak tides because the surrounding ocean is too large to host tidal resonances. Here we show, using an established numerical global tidal model and paleogeographic reconstructions, that the Cryogenian ocean hosted diminished tidal amplitudes and associated energy dissipation rates, reaching 10-50% of today's rates, during the Snowball glaciations.

Snowball Earth climate dynamics and Cryogenian geology-geobiology.

Geological evidence indicates that grounded ice sheets reached sea level at all latitudes during two long-lived Cryogenian (58 and ≥5 My) glaciations. Combined uranium-lead and rhenium-osmium dating suggests that the older (Sturtian) glacial onset and both terminations were globally synchronous. Geochemical data imply that CO was 10 PAL (present atmospheric level) at the younger termination, consistent with a global ice cover.