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Us, probably. Traditionally, the circulating water gets colder as it reaches the arctic circle and submerges, since cold water has a higher density than warmer
by IAmEveryone 9y ago
Us, probably.
Traditionally, the circulating water gets colder as it reaches the arctic circle and submerges, since cold water has a higher density than warmer water.
But: melting ice in the arctic releases freshwater. This reduces the salinity at the surface of the Northern Atlantic. Water with lower salinity is lighter. Therefore, this water no longer submerges, and the circulation is slowed down.
- bassman9000 9y agoThe studies differ on the timing of when that weakening began. Thornalley’s record, which spans those 1,600 years, suggests it started at the end of the little ice age, a period from about A.D. 1350 to 1850, when solar and volcanic influences depressed temperatures across the Northern Hemisphere and glaciers and ice sheets expanded. As the little ice age ended and temperatures warmed, ice melted and freshwater flooded into the North Atlantic. The results suggest the current state of the AMOC is the weakest it has been over that whole long record. Whether today’s state is just a continuation of that reaction or whether global warming has also started to chip in is not clear, he says. Caesar, meanwhile, put the turning point toward a weaker AMOC in the mid-20th century, suggesting it is due to the influence of human-caused warming. Her team’s record, however, does not extend as far back. Indications of the process having started (edited) before humans could be responsible for it (few hundred years ago).
- mirimir 9y agoSure, maybe AMOC has been weakening since the end of the little ice age. But that doesn't matter so much if anthropogenic warming is weakening it now.
- jonhendry18 9y agoIt may have started back then but accelerated or been exacerbated because of human activity.
- ThomPete 9y agoWhere is the data that shows that.
- matte_black 9y agoCouldn’t it be fairly trivial to raise the salinity? We have tons of salt. Enough at least to kick the can further down the road.
- dbasedweeb 9y agoJoking, right? If not, I’ll match your talent for understatement with my own: the ocean is very big.
- matte_black 9y agoBig is still not infinite. There must be some quantity of salt we can dump a year to raise salinity. We should be rigorous, and find out what that quantity is. If we can change a climate, we can change an ocean.
- ggm 9y agoThe assumption there is a feasible application of something in a location to remediate a world wide problem is attractive but I think built on faulty logic. To try an analogy, gluing a broken cup back together doesn't make it never have broken. Yes, we probably can re-salinate a flow to attempt to alter its dynamics. We'd also have altered its salinity profile in ways which have repercussions on e.g. cod fisheries, or krill, or other things. Thats the problem with complex biological systems with lots of interrelated parts: they don't reverse with simple tweaks because once you change one part, you change lots of parts in unexpected ways. (I did once study this stuff back in the 80s and was very bad at it, but what I recall of even two-actor predator-prey relationships is that they are remarkably complex, cyclical, and do not just return to the same stable place if you alter them trivially. I believe this is probably even more true for physical systems like weather and climate)
- ojbyrne 9y agoI suspect that like most “magic” solutions to environmental problems, this would cost significantly more than just reducing CO2 emissions.