Thanks for the link, the thing I wanted to know and this paper answered was how they measured the current and this was the cool part! They used voltage induction caused by salt water flowing past abandoned submarine telephone cables. [1]
> I applied Bayesian data analysis to observations from submarine cables and tide gauges to infer the changes in the Florida Current transport at 27°N during 1909–2018.
These are important techniques for deriving a proxy for missing historical flow data. I have no confidence that the algorithms model a real-world trend but it seems to have promise as one component of a decent future model.
I followed qserasera's link to the Nature paper. The Methods [1] section says:
> I also use Florida Current transport from submarine telephone cables at 27∘N between West Palm Beach and Grand Bahama (Figs. 1b and 2). Using electromagnetic theory, one can estimate changes in the flow from voltages induced across the cable due to the transport of charged particles by the variable current.
I don't think there's enough information to make that conclusion. The strongest conclusion I think we can make is that ocean current's changing is almost certainly going to change regional climates in unexpected ways.
Would be really interesting to have a qualitative description of where global ocean flows are increasing, if they are decreasing here? Or if in general, ocean circulation / transport is undergoing some change?
Or watching the video commented below, maybe it's the weakening that's happening because of the warming and freshening of arctic waters like around Greenland.
There isn't a "conservation of flow" principle for liquids, so there's no need to go looking for a flow increase somewhere else because this flow is decreasing.
My takeaway from a one year oceanography course is that ocean currents have more in common with biology than computing: they're complex, can change as the result of propagation of relatively small changes, and are inconceivable in scale.
