Naturally, the world reacted with anger when Donald Trump announced the nation's withdrawal from the Paris Climate Agreement, but fewer people are more frustrated than Leonardo Dicaprio who has been an advocate for the fight against global warming for most of his career.

Leonardo DiCaprio at 'Before The Flood' premiereLeonardo DiCaprio at 'Before The Flood' premiere

'The Revenant' star took to social media to express his disappointment over the President's controversial decision last week, but with it came a message of hope and encouragement. After all, the news comes only months after his work on Fisher Stevens' 'Before the Flood' documentary.

'Today, the future livability of our planet was threatened by President Trump's careless decision to withdraw the United States from the Paris Agreement', he told his 17 million followers on Facebook. 'Our future on this planet is now more at risk than ever before. For Americans and those in the world community looking for strong leadership on climate issues, this action is deeply discouraging.'

He finished by encouraging fans to take action against this decision, and to use various platforms to stand up and fight for the survival of the planet. 'Now, more than ever, we must be determined to solve climate change, and to challenge those leaders who do not believe in scientific facts or empirical truths', he continued. 'It is time for all of us to stand up, organize, fight back, and channel our energy into grassroots political action.'

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Earlier this year, the Academy Award winning movie star attended the People's Climate March which was held in protest of some of Trump's policies and intentions for the US. But Leonardo is not the only one to have spoken out against the shocking development. World leaders have reacted in shock over the new decision; after all, every country in the world has signed the Paris Agreement apart from Nicaragua (the leader of which believes the pact should be taken further) and Syria (whose conflicts are far too crippling for them to be worrying about such a thing at the moment).