Discovery Channel's 'Frozen Planet' Won't Blame Man-Made Global Warming -- And Enviros are Upset

Since mid-March, Americans with access to the Discovery Channel on Sunday evenings have perhaps been tuning in to the wildlife documentary "Frozen Planet." The series finale was extended to end on Earth Day -- Sunday, April 22 -- with its final episode detailing the effects of climate change on the harsh yet fragile ecosystem of the Arctic.

(Related: 'Frozen Planet' premiers in U.S. with 'amazing natural drama' -- climate change rhetoric to follow)

According to environmentalists and some scientists though, there was something missing from last night's episode "On Thin Ice." That is, what is causing these effects.

On Friday, the New York Times reported the show was being criticized by some in these groups for being too accommodating and "afraid" of upsetting "dismissives," or those who don't consider global warming a man-made problem:

“Many organizations, and it sounds like Discovery is one of them, appear to be more afraid of being criticized by climate change ‘dismissives’ than they are willing to provide information about climate change to the large majority of Americans who want to know more about it,” said Anthony Leiserowitz, the director of the Yale Project on Climate Change Communication.

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“It’s kind of like doing a powerful documentary about lung cancer and leaving out the part about the cigarettes,” said Bill McKibben, a scholar and climate change activist. “There’s no scientific mystery here: the poles are changing because we’re burning so much carbon.”

The Times reports series producer Vanessa Berlowitz saying they did not include a cause to climate change one way or the other because it “would have undermined the strength of an objective documentary, and would then have become utilized by people with political agendas." She told the Times they didn't want people saying "'Don't watch this show because it has a slant on climate change.'"

(Related: Faking wildlife scenes not uncommon in BBC documentaries)

Discovery President Eileen O'Neill is reported as emphasizing the fact this was a natural history documentary. Even David Attenborough who narrated the final episode of "Frozen Planet" -- actor Alec Baldwin narrated the pervious six of the series in the U.S. -- leaves some questions open for debate:

Shown standing at the North Pole, Mr. Attenborough told viewers: “The days of the Arctic Ocean being covered by a continuous sheet of ice seem to be past. Whether or not that’s a good or bad thing, of course, depends on your point of view.”

Mr. Attenborough then noted the new opportunities for energy exploitation and commercial shipping. But he did not note that the vast majority of scientists believe that human activities are contributing to the warming trends evident there.

Others have weighed in on what wasn't said in the series in comments and on Twitter, including singer and actress Bette Midler.

Still, it should be noted that the majority of comments and tweets on the series were positive and focused on the stunning footage of the environment and wildlife imagery.

What do you think? Was Discovery and BBC, which also co-produced the series, correct to leave discussion over the cause of climate change out of the series?