This kind of stuff masked you feel good to say but the UK isn’t going to stop the US if it (somewhat foolishly in my opinion) decided that it was going to take Greenland. Neither is the EU.
No it would be a point of no return. But the "non-kinetic" consequences would go both ways.
It's not an exercise we should entertain, though the EU needs to step up in a very serious way and spend billions of Euros adding new equipment to Greenland to beef up detection and defense.
How will the EU get this arctic warfare equipment to Greenland? If the EU is so ready and willing to use this equipment, maybe they should deploy it to Ukraine instead.
The US literally has bases in Alaska and Greenland and deals with these temperatures regularly.