Former US vice president Al Gore has defended himself against accusations of hypocrisy over the decision to sell his TV network to a company funded by profits from oil and gas.
Gore, a longstanding campaigner on environmental and ecological issues, sold Current TV, the network he founded in 2005, to the Al Jazeera network in January.
The deal will give Al Jazeera, which is owned by the government of Qatar, stronger distribution in the US.
Qatar has the biggest per capita carbon footprint of any nation in the world, and funds the channel largely through profits from its liquefied natural gas exports.
Al Jazeera's editorial independence has repeatedly been questioned. Staff protested last September at a decision by its director of news, Salah Negm, to include a speech by the Qatari leader Hamad bin Khalifa Al Thani, in a report on the Syrian crisis.
The Qatari government has also stepped up efforts to assert control over the network's English language channel, Al Jazeera English.
Gore's new book, The Future, argues that a powerful lobby of corporate interests - particularly big energy companies - has manipulated government and media, hoodwinking the public and promoting their own self-serving agenda.
But he denied that the sale of his TV channel was incompatible with his much-trumpeted principles.
"I understand that perspective, but I don't agree it," he told the BBC.
"All of the US networks that carry news and comment and information also carry heavy advertising from carbon companies. Tthere's no question about it. Current did not. Al Jazeera does not. It has no commercials whatsoever.
"The fact is that Al Jazeera has long since established itself as a widely respected news-gathering network, and it has done a good job. Its climate coverage has been outstanding."
Gore said he hoped the sale would spur US networks into taking climate change more seriously.
"I hope that other networks will be encouraged by the addition of Al Jazeera to the TV dial, to upgrade their own climate reporting," he said.
"Here in the US, we went through an entire presidential election last year, in a year that was the hottest year for the US: 60 percent of the country in complete drought; $110 billion in climate-related disaster damage; Hurricane Sandy destroying parts of lower Manhattan and New Jersey.
"And not one single question was asked by any member of the national news media to any of the candidates for president about the climate crisis."
He blamed a "dysfunctional" government and media for allowing themselves to become dominated by corporate interests.
"Politicians have trouble making the right decisions in the public interest when they spend so much time worrying about the opinions of these large corporate donors and special interest donors," he said.
"TV selectively presents information that is paid for by large corporations and special interest groups."
Gore said politics and the media were in thrall to corporations that sought to influence the political discourse to suit their own agendas.
"We have clearly seen the partisanship and levels of vitriol growing. This is directly connected to the influence of big money, anonymous contributors, and corporations pretending to be people.
"US politics has fallen into a state of disrepair. It can be fixed, but we need to recognise our democracy has been hacked."
But he explicitly ruled out a re-entry into politics under a future administration led by Hillary Clinton. "I'm a recovering politician," he said. "The chances of a relapse have been diminishing long enough that I have increasing confidence I won't yield to that temptation again."