Summary: The melting Arctic is not the source for less saline Nordic Seas. It is the Gulf Stream that has provided less salt. A new study documents that the source of fresher Nordic Seas since 1950 is rooted in the saline Atlantic as opposed to Arctic freshwater that is the common inference.The common inference was always wrong. The 1950-1970's period had a cooling trend, with increased glaciation. In other words, the cause of the decreased salinity of the Nordic seas always had to be something other global warming.
The Nordic Seas have freshened substantially since 1950. This has happened at the same time as there has been observed increased river runoff and net ice melting in the Arctic.Correlation is not causation. And there was not "increased melting" during the early part of that period.
"It has been a concern that a layer of Arctic freshwater could impede the Gulf Stream's Arctic branch. Going back in time -- into and through ice ages -- such a freshwater lid has been understood to reduce ocean circulation and thus the Gulf Stream's poleward heat transport," says Tor Eldevik.It has already been shown that the Gulf Stream does not, in fact, convey significant amounts of heat to the Arctic regions. And it is not responsible for the "unexpectedly" milder climate of Norway and Europe.
The researchers from the Bjerknes Centre have analysed the available observations back to 1950 and conclude that the changing salt content in the Nordic Seas is explained by the variable salinity of the Gulf Stream's Arctic branch entering the seas from the south.
Although not part of the present study, it appears to be several reasons for the freshening of the Atlantic source waters. A dominant explanation is a general increase in net precipitation over the North Atlantic Ocean (which may very well relate to global climate change). The contribution is spread over the Gulf Stream system, and accordingly transported further northward.On the other hand, it might not be due to climate change during the 1950-1970's time period, as explained above. It might just be a natural variation.
We have 65 years of real-time data. We have data that has been teased out of the fossil record and out of the glaciers themselves that can act as "proxies" for the real-time data. How accurate the proxy data is unknown.
On the other hand, North America separated from Europe about 100 million years ago. Presumably, the Gulf Stream has been in operation, or in hiatus, since then. It is raving absurdity to assume we have enough information to actually understand what is happening here.
And the proof of that is the consensus that was the "common inference."