This is serious no doubt. However, I don't think WW3 will last very long. Our technology is such that even IF Putin was crazy enough to launch, drones plus a good nuclear defense shield would probably shoot down anything he sent up. Then, a full nuclear strike against Russia would send them back into the Stone Age. No more Russia, and no more stupid bullshit.
At this point, China isn't dumb enough to back Putin's crazy Nuke threat either. They'll continue to sit this one out, smile, and rake in the profits. Oh, and they'll be the first ones into the nuclear wasteland once known as Russia, in order to take whatever natural resources (underground) that remain, just like they're currently doing in Afghanistan.