“Frozen Planet,” the seven-hour series that has attracted millions of viewers to the Discovery Channel in recent weeks, shows Earth in extremis. On this planet, the poles are violently cold, yet are also atypically vulnerable to the warming trends that are endangering polar bear populations and causing huge chunks of ice to break off Greenland and Antarctica.


All of it — the struggling polar bears, the collapsing ice shelves — is shown in stunning high definition. It is accompanied by the voice of Alec Baldwin, who narrates the series and says categorically, “The ends of the earth are changing.”


What the series never assesses, however, is why.


The vast majority of scientists agree that human activities are influencing changes to the climate — especially at the poles — and believe that the situation requires serious attention. That scientific consensus is absent from “Frozen Planet,” for reasons that shed light on the dilemma of commercial television, where the pursuit of ratings can sometimes clash with the quest for environmental and scientific education, particularly in issues, like global warming, that involve vociferous debate.


Including the scientific theories “would have undermined the strength of an objective documentary, and would then have become utilized by people with political agendas,” Vanessa Berlowitz, the series producer, said in an interview.


She added, “I feel that we’re trying to educate mass audiences and get children involved, and we didn’t want people saying ‘Don’t watch this show because it has a slant on climate change.’ ”


This approach — anticipating criticism and tiptoeing around it accordingly — is a reflection of the political and ideological fury that infuses many conversations about climate change. Some scientists say that the politicization of the subject has succeeded in causing governments, corporations and media outlets to shy away from open discussion about it.


“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.


The people who are dismissive of human effect on climate change make up about 10 percent of the American population, according to Dr. Leiserowitz’s research, but they sometimes drown out the broader conversation about the subject, making themselves seem more numerous than they are.


In private, some people involved in the production said that Discovery and its production partners, including the BBC, were wary of alienating any of the potential audience for “Frozen Planet.”


First and foremost, “Frozen Planet” is a natural history documentary, said Eileen O’Neill, the president of Discovery. The series seeks to entice viewers with footage of seals, penguins, polar bears and other animals of the polar regions. Here’s the visual evidence, it asserts, of a warming planet; make of it what you will.


Ms. O’Neill said of viewers, “You’ve got to get them to care.” To that end, penguins on loan from Sea World were one of the main attractions at the New York premiere party of “Frozen Planet” last month; another was the ice sculptures that were rapidly melting in the unusually warm March air.


Nature series like “Frozen Planet” aren’t usually the highest-rated shows of the year for Discovery, which is among the top 10 cable channels for viewers ages 25 to 54. But the series help to give the channel an identity and promote the channel to new viewers. To date, each premiere of a new “Frozen Planet” episode has attracted about 1.1 million viewers.


Discovery and the BBC jointly decided what to film and how to pay for the production of “Frozen Planet,” as they did for the previous series “Blue Planet,” “Planet Earth” and “Life.” The documentary makers felt a sense of urgency to focus on the polar areas, Ms. Berlowitz said, “because this region is changing faster than any other on Earth — we needed to make this series now.”


One of the seven episodes, “On Thin Ice,” was devoted to climate change. It placed the narrator of the British version of the series, David Attenborough, in front of the camera to show how warming trends are affecting humans and animals in the Arctic. 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.”