Consider a strange article NBC News recently ran, asking readers to confess their climate “sins.” “Tell us: Where do you fall short in preventing climate change? Do you blast the A/C? Throw out half your lunch? Grill a steak every week? Share your anonymous confession with NBC News.”

This, from a network news outlet that Americans with fond memories of Tom Brokaw’s reassuring voice still think of as objective and unbiased. The article isn’t just biased in favor of the religio-environmentalist view of carbon offsets being the new indulgences, it unapologetically promotes such a view.

That journalists and editors are overwhelmingly liberal is nothing new. But the imbalance is arguably getting worse. Even financial journalists, once thought to lean conservative, are overwhelmingly liberal. Last year, a survey of financial journalists at places like The Wall Street Journal, New York Times, and Washington Post found that more than 58 percent identified as either “very liberal” or “somewhat liberal.” Less than 5 percent said they were very or somewhat conservative.

Now more than ever, media outlets should recognize that the myth of objectivity won’t lend them credibility. In fact, a failure to admit bias will eventually undermine their credibility, not least because their reporters and editors will spout off on Twitter, or email and text chains will be leaked, or their readers will notice how errors and omissions always seem to benefit liberals and hurt conservatives.