By Sarah Mills

LONDON (Reuters) - Former U.S. Vice President Al Gore said on Friday that President Donald Trump's rejection of the Paris climate change agreement was fueling, rather than weakening, momentum among environmental activists.

Gore, whose follow-up to his 2006 Oscar-winning documentary "An Inconvenient Truth" is showing in movie theaters worldwide this month, said governments and companies had stepped up since Trump's decision in June to withdraw from the 2015 global pact.

"The entire world the next day re-doubled their commitments to the Paris agreement and in the U.S, the governors of our largest states and hundreds of mayors, thousands of business leaders all stood up to fill the gap and said 'We are still in the Paris agreement,'" Gore told Reuters Television.

"I do think that the reaction to Donald Trump is actually driving much more momentum in the climate movement," he added.

Gore's new documentary, "An Inconvenient Sequel: Truth to Power," argues that fighting climate change is a moral battle, on a par with the civil rights movement in the United States or the fight for gay rights.

Shot mostly before Trump's election, it also shows the Republican on the 2016 campaign trail promising to abolish environmental regulations and boost the coal and oil industries.

"An Inconvenient Truth" is credited with bringing climate change into mainstream political discourse in the United States a decade ago. It won the best documentary Oscar in 2007 and helped propel Gore to a Nobel Peace Prize, which he shared with the Intergovernmental Panel on Climate Change.

(Editing by Dan Grebler)