1/ The idea that the Arctic holds the key is a very northern-centric one. The Antarctic is more likely to be the real key, with the big climate changes (e.g. the ending of the last glaciation) progressing up from the south.
2/ Furthermore the Gulf Stream is purely wind-driven. The thermohaline effect is just one of drivers the Deepwater Circulation.
'Gulf Stream' is not synonymous with 'Thermohaline Circulation' - which is not synonymous with 'Atlantic Meridional Circulation' (AMOC). They are three separate phenomena with three different definitions. NOAA define them as follows: “The terms Atlantic Meridional Overturning Circulation (AMOC) and Thermohaline Circulation (THC) are often used interchangeably but have distinctly different meanings. The AMOC is defined as the total (basin-wide) circulation in the latitude depth plane, as typically quantified by a meridional transport stream-function. Thus, at any given latitude, the maximum value of this stream-function, and the depth at which this occurs, specifies the total amount of water moving meridionally above this depth (and below it, in the reverse direction). The AMOC, by itself, does not include any information on what drives the circulation.” (Source: Chapter 4, Potential for Abrupt Change in the Atlantic Meridional Overturning Circulation, Final Report, Abrupt Climate Change (noaa.gov) ) See also https://courses.seas.harvard.edu/climate/eli/Courses/EPS281r/Sources/Thermohaline-circulation/1-Rahmstorf_EQS_2006.pdf
3/ Re: "Each year we lose around 13% of the Arctic ice sheet." In fact the WWF ink you provided states that "Each year we lose around 13% of the Arctic sea ice." There is an essential difference between these two terms.
Unfortunately the WWF link is also completely wrong. (Where do they get their staff from?) Study the link (below) to the authoritative Norwegian Nansen Arctic ROOS website which shows that, in fact, arctic sea-ice is declining at between 2.5% and 10% per DECADE. https://web.nersc.no/WebData/arctic-roos.org/observation/ssmi_range_ice-area.png
