North of the Alps temperature would drop considerably. South of the Alps, probably fine due to the thermal mass of the mediterranean sea. However, for the whole Europe you would see a massive drop in rainfall, since basically all the humidity comes from the Atlantic's warm air that carries a lot of it.
Additionally, Carribeans, Mexico and South of the US would also be fucked since the energy wouldn't disperse and all the heat and humidity would stay there. Hurricanes would be much more violent, with way more rain, and likely more frequent.
Labrador current might become weaker though, but it is not a given. Currently, the waters from the gulf stream cool down and sink to the bottom of the ocean, so they don't displace the artic waters and hence are not likely the cause of how cold north eastern US is.
None? It is not certain any country will benefit. Countries built their infrastructure and population centers according to the weather of the location. If the weather changes probably every country will have to adjust.
If you are asking which area will benefit from climate change I would say Siberia as it will become increasingly important due to the northern corridor remaining ice free and because a lot of people will be displaced by weather/sea level. And that place is empty. Additionally, it has nice farming soil which right now is not used since there are easier places to farm but in a warming world this could change
Additionally, Carribeans, Mexico and South of the US would also be fucked since the energy wouldn't disperse and all the heat and humidity would stay there. Hurricanes would be much more violent, with way more rain, and likely more frequent.
Labrador current might become weaker though, but it is not a given. Currently, the waters from the gulf stream cool down and sink to the bottom of the ocean, so they don't displace the artic waters and hence are not likely the cause of how cold north eastern US is.