MSNBC anchor Chris Hayes’ admission that climate change is a “ratings killer” has infuriated environmentalists who accused the liberal network of being more concerned about its bottom line than with fighting global warming. Asked about his network’s lack of climate-change coverage, Mr. Hayes tweeted Tuesday that “almost without exception. every single time we’ve covered it’s been a palpable ratings killer. so incentives are not great.” His frank assessment was met with chuckles from climate skeptics like Anthony Watts, who called it “hilarious, but true,” given that global warming typically brings up the rear on polls and surveys of top voter...