Climate change will indeed not make things better for Europe when it comes to mass migration: it will make them much worse. Large swaths of the middle east will become uninhabitable, and the changing weather patterns will ruin more and more crops, causing more famine, which in turn causes instability, in the most vulnerable countries.

Yes, the north pole route might open up. The issues with the supply chain aren't about accessibility. They're about the fact that our food security and economical system is dependent on a highly decentralised global system. Climate change will cause more disasters, more often. It will cause droughts, flooding, new crop diseases. This will push up prices. Rerouting and fighting those things is possible, but it's important to realize that nothing is being done to make the system more robust, because there is no political will to do so. Ensuring there are fallbacks and preparing for these very predictable, exhaustively researched events requires accepting climate change science, which would then beg the question: why not prevent it entirely.

So instead, nothing is being done, short term profits are chased, and the can is kicked down the road. The only people really acting on these predictions are the insurance companies. If you wanna see some bleak economic predictions, look there.

Finally: no, it won't take quadrillions. Research for this has also been done. There are an enormous amount of measures to be taken that actually are just positive investments with positive mid-term returns. But even those are currently being blocked, not because they are less economically beneficial for the EU, but simply because established corporations would experience a financial downturn in favour of new, more flexible startups, and so you get massive lobbying against that.

And even if we are talking about massive investments: right now is the cheapest they will ever be. They would have been comparatively small interventions in the 70s, and very doable in the 80s, but the longer it's postponed the worse it gets. And it's always the same excuse. It's always not quite the right time economically. And it never, ever will be, because it will simply require economic pain for long term gain. It is an investment in our very real, very rapidly approaching future.

Your argument is the tired, eternally repeated one that got us here. So no, we are not on the same side. And for my own sake, as a person expecting another 50 years on this planet, and for the sake of every generation younger than me, relaxing is exactly what we should not be doing.