When CBC science correspondent Bob MacDonald identified climate change as one of the top 10 science stories of 2013, he said it's time to stop denying its reality and get on with finding solutions. Bravo to MacDonald, and to CBC for meeting its responsibilities as a public broadcaster.

But where on the network's flagship news broadcast The National are the stories, the sources and the sustained attention that could help Canadians understand and address what is possibly the greatest challenge humanity has ever faced?

Instead, on the Jan. 17 edition, CBC commentator Rex Murphy, who sometimes acts like a resident apologist for the fossil fuel industry, devoted his weekly commentary to undermining citizens who dare to oppose vested interests and work for a habitable planet for future generations.

Specifically, Murphy tore into Neil Young's comments on his cross-country Tar Sands tour. Yes, Young's comparison of the Athabasca bitumen sands project to Hiroshima was overwrought. But it's not unreasonable to consider the project an environmental war crime.

It has been estimated that 300,000 extra deaths per year are already attributable to the consequences of global warming -- in terms of sheer mortality, the equivalent of over two Hiroshimas. The amount of oil to be unleashed over time by the Athabasca bitumen sands has been estimated to have the potential to raise the planet's average temperature beyond the generally accepted tipping point of two degrees -- on its own.

Calling rhetorically for a balanced discussion, Murphy went on to offer a one-sided encomium on the project's presumed benefits, and denounced Young for his "one-sided and overtoxic condemnations... Young has failed to be fair; and therefore, he has also failed to be persuasive."

Seemingly without irony, the speaker speaks of himself. Perhaps, in combining his literary proclivities with his "fossilized" politics, Murphy wishes to brand himself a new species of dinosaur -- Tyrannothesaurus Rex.

Why is it that Rex Murphy appears regularly on the network's flagship news program, while voices of environmental sanity like David Suzuki or Naomi Klein don't?

To be sure, CBC is still capable of the excellent watchdog journalism for which it has been renowned in the past; a recent collaborative series on offshore tax havens is an example. But informed long-term observers like the Friends of Canadian Broadcasting worry that faced with political and funding pressures from the federal government, CBC is at risk of sliding down a slippery slope, from a respected public broadcaster, to a state broadcaster on an increasingly tighter leash to the government of the day. Off the record, respected CBC journalists talk about "leftwing phobia" and political timidity at the level of management.

If we want a society alert to the danger of climate change, excessive dependence on fossil fuel exploitation and consumption, and the violation of aboriginal treaty rights, then revitalizing CBC's journalism needs to be part of a more hopeful picture.

Robert Hackett teaches communication at Simon Fraser University; his publications include a number of books on news and political communication, including most recently the co-edited Expanding Peace Journalism (Sydney University Press, 2011). He is on the organizing committee of the annual Media Democracy Days.