Earth is warming, so why is it so cold?

A "polar vortex" is bringing intense cold and heavy snow to large swaths of the US and Canada. How is this winter weather related to climate change?

Source: https://www.dw.com/en/earth-is-warming-so-why-is-it-so-cold/a-71661055?maca=en-rss-en-all-1573-rdf