Lots of tweets recently about polar vortex effects, jet-stream waviness, crazy weather etc. What can be attributed to global warming and what cannot? It is hard to answer with certainty, but without being specific it usually helps to bear in mind the following:

The thermodynamic effects of global warming - those related directly to temperature itself - are generally quite robust and incontrovertible. Dynamic effects - shifts in jet streams, expansion of the tropics, unstable polar vortices - are more sensitive and less well understood.

This doesn't mean they aren't happening, but the jury is still out on many of them, both from an observational and theoretical point of view. I would say 'more research on these topics is needed' but as you know Biden recently signed an executive order banning that phrase.