Leonardo Dicaprio joined President Barack Obama and atmospheric scientist Katharine Hayhoe in a conversation about global warming during a new event called South by South Lawn (SXSL) at the White House. He was also there to promote his new climate change documentary 'Before the Flood'.

Leonardo DiCaprioLeonardo DiCaprio talks global issues with Barack Obama

'The Revenant' actor moderated the conference last night (October 3rd 2016) in Washington, D.C., where they talked about the work that was already being done within the US and around the world to tackle the issue, and what we can expect from the world if certain other changes are not made soon under the new presidential leadership.

'We must empower leaders who not only believe in climate change but are willing to do something about it', DiCaprio said in his opening speech, apparently taking aim at Republican Presidential candidate Donald Trump, who has made his skepticism about climate change very clear in the past. 'The scientific consensus is in, and the argument is now over. If you do not believe in climate change, you do not believe in facts, or in science, or empirical truths; and therefore, in my humble opinion, should not be allowed to hold public office.'

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Obama responded by recapping the work the US government has done so far to combat climate change including improving fuel-efficiency in cars, investing in clean energy, increasing wind and solar power, and launching the Paris Agreement to ensure that other nations around the world take the appropriate steps to reduce their carbon footprint. However, he also assured the audience that a lot more work needed to be done.

Watch the full discussion below:

'Climate change is happening even faster than the predictions would've told us five years ago or ten years ago. What we're seeing is changes in climate patterns that are on the more pessimistic end of what was possible', he said. 'We're really in a race against time.'

The discussion took place ahead of the US premiere of DiCaprio's 'Before the Flood' documentary, which he produced and starred in and which has been directed by Academy Award winner Fisher Stevens (producer of 'The Cove' and 'Racing Extinction'). The film sees the actor travel the world and meet with a number of different important people including Pope Francis and John Kerry to explore how deep the issue of climate change really goes.

'Before the Flood' hits theaters on October 21st and will air on the National Geographic Channel from October 30th.