This term was in vogue several years ago, but seems to have been surpassed by "climate change" (next item). One problem with "global warming" is that while it may be true in an average sense, it frequently does not resonate in an instantaneous sense. When you've lived through a "polar vortex" and are awaiting the rumored arrival of another one, "global warming" seems neither likely nor a bad idea.
This is the phrase currently in vogue. Its two main faults are that (a) change is not necessarily bad and (b) change is inevitable (except, as some wag once noted, from a vending machine).
With those thoughts in mind, I would like to propose a new phrase that I think is both more descriptive of current climate phenomena and better conveys a sense of concern about them:
Bipolar Climate Disorder