The most optimistic estimate of deep-water outgassing south of 60 ° S is 0.36 Pg C yr⁻¹. Even if that rate tripled and persisted unabated, it would take more than 800 years to add 895 Pg C (which would be what it would require to justify the press release’s claims of “doubling”)
What the salinity reversal can do is:
- Expose ice shelves to warmer subsurface water, accelerating sea-level rise.
- Reduce the Southern Ocean’s role as a sink by a few tenths Pg C yr⁻¹, nudging the global ocean sink (~2.7 Pg C yr⁻¹) downward.
- Perturb atmospheric circulation patterns, with knock-on effects for the Atlantic overturning (but those links remain speculative).