The battle between CNBC anchor Joe Kernen and environmentalists is escalating on Twitter and over the airwaves.

Kernen, co-host of CNBC’s “Squawk Box,” on Friday bashed “enviro-socialists” who are criticizing him, and shortly afterward added, “It is a bona fide cult.”

Kernen’s remarks come as the anchor and his network are under fire from climate advocates. His Twitter exchanges with critics can be viewed here.

A June report by the liberal watchdog group Media Matters for America said more than half of CNBC’s 2013 climate coverage cast doubt on human-induced climate change.