←back to thread

480 points riffraff | 1 comments | | HN request time: 0.208s | source
Show context
taylorlapeyre ◴[] No.44461488[source]
The deep-ocean vent south of Antarctica is real but small, on the order of a few-tenths Pg C yr⁻¹. The claim that it could double atmospheric CO₂ exaggerates the flux by three orders of magnitude relative to observed values and known physical limits.

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).

replies(6): >>44461561 #>>44461661 #>>44462991 #>>44463052 #>>44463345 #>>44463493 #
irthomasthomas ◴[] No.44463052[source]
As water is more dense than ice, wouldn't the sea level drop when the ice shelf melts?
replies(3): >>44463122 #>>44463137 #>>44465525 #
1. Avshalom ◴[] No.44465525[source]
Not sea ice obviously but there are places where sea level is "dropping" https://en.m.wikipedia.org/wiki/Post-glacial_rebound