For example: +4 degrees C global average would mean about +2 in Ireland, while inland USA soars to +8.
I see no basis for this assertion.
Where the atmosphere or an extensive ocean is able to convect heat polewards, the poles will be warmer and equatorial regions cooler than their local net radiation balances would predict.*
In the extreme, the planet Venus is thought to have experienced a very large increase in greenhouse effect over its lifetime,[3] so much so that its poles have warmed sufficiently to render its surface temperature effectively isothermal (no difference between poles and equator).
Both palaeoclimate changes and recent global warming changes have exhibited strong polar amplification, as described below.
Both palaeoclimate changes and recent global warming changes have exhibited strong polar amplification, as described below.
This is true, but it is also irrelevant. The keyword 'global average' - global heating will not be uniform. The closer an area is to the poles, more heating will happen. Europe is pretty far north so the effects will be pretty large. Large enough to offset the Atlantic streams? Perhaps, perhaps not.
I'm more worried about changing precipitation patterns, to be honest.