This sketch explains why a cold winter does not disprove global warming, despite what the skeptics so love to claim.
While only an over-simplified sketch, the picture speaks for itself. If you see both harsher winter cold snaps and hotter summer heat waves, that's one of the tell-tale symptoms of global warming!
As indicated in the sketch, the extra heat energy goes into powering wider weather swings.
We can always debate as to why the warming might be occurring. But it is definitely occurring, despite the harsh winter conditions of January 2018.
If you want to see something about causality, go see the article titled "Do We Fight Global Warming or Not?", dated 4-15-17, on this website.