It’s been talked about for a while (in fact I covered this 6 years ago), but a lot of things have been said about the potential collapse of the Atlantic Gulf Stream, also known as the Atlantic Meridional Overturning Circulation or AMOC. This global current that keeps Europe and North America (but especially Europe) from being covered in ice is increasingly under threat of slowing or even stopping. The results would be catastrophic.
The point about tipping points is, that by definition a tipping point can’t be restored. Once it colapses, the areas it cools will be even colder and the warm areas that get cooled by it, will turn into deserts. Agriculture in northern Europe will not be possible. Rain in the Amazone will be limited.
Compare the climate of northern Europe to the correlating climate of Western Canada. The reason why it’s not as cold in Europe is that AMOC keeps it warmer