Speaking just days after the subject of climate change failed to get a mention in the US presidential debates for the first time in 24 years, Sir David Attenborough told the Guardian: "[It] does worry me that most powerful nation in the world, North America, denies what the rest of us can see very clearly [on climate change]. I don't know what you do about that. It's easier to deny."

Asked what was needed to wake people up, the veteran broadcaster famous for series such as Life and Planet Earth said: "Disaster. It's a terrible thing to say, isn't it? Even disaster doesn't do it. There have been disasters in North America, with hurricanes and floods, yet still people deny and say 'oh, it has nothing to do with climate change.' It visibly has got [something] to do with climate change."

But some US politicians found it easier to deny the science on climate change than take action, he said, because the consequence of recognising the science on man-made climate change "means a huge section from the national budget will be spent in order to deal with it, plenty of politicians will be happy to say 'don't worry about that, we're not going to increase your taxes.'"

Neither Barack Obama or Mitt Romney mentioned climate change in three TV debates, despite a summer of record temperatures and historic drought in the US.

Romney used Obama's commitment to taking action on climate change as a joke in his convention speech. The president later hit back by saying "and yes, my plan will continue to reduce the carbon pollution that is heating our planet because climate change is not a hoax. More droughts and floods and wildfires are not a joke." However, environmentalists have been critical of Obama's silence on the subject and the Green party presidential candidate, Jill Stein, went as far as saying it meant he was, in effect, "another climate denier".

Attenborough said he thought the US's attitude towards climate change and the environment was not just because of politics, but because of the country's history. "[It's] because they're a pioneer country. There has been the wild west, the western frontier… that's still there, you see it in the arms business, the right for everyone to bear arms. It's part of the pioneer stuff that you've [Americans] grown up with."

 

• You can listen to a longer version of this interview at Guardian.co.uk/scienceweekly on Monday 29 October