Former American vice president Al Gore, noted for his strong stance on climate change, has written a book arguing that the public is willing to make changes in their behaviours to reduce the impact of climate change.
Mr Gore spoke to Today presenter James Naughtie about his optimism that the growing movement against climate change would spur the world's leaders to act.
He explained that while individuals changing light bulbs and fitting insulation played a part, "more important is changing the laws and policies".
But with sustained pressure, he says, there is cause to be hopeful that progress can be made in fighting carbon emissions.
This is an extended version of the broadcast interview.