This past Tuesday morning, Leonardo DiCaprio addressed world leaders assembled for the UN Climate Summit in New York, and urged them to take action against climate change. He recently marched with 400,000 others in the People's Climate March, and has cemented himself as one of the world's most high-profile activists on climate change.

According to the Huffington Post, DiCaprio told leaders to address "the greatest challenge of our existence on this planet." He went on to say, "As an actor, I pretend for a living. I play fictitious characters often solving fictitious problems. I believe humankind has looked at climate change in that same way... My friends, this body - perhaps more than any other gathering human history - now faces that difficult task. You can make history... or be vilified by it."

DiCaprio has suffered backlash since his speech, as many think the Hollywood star's lifestyle reveals a double standard on the issue of climate change. The Daily Mail reports that he spent his World Cup vacation on the fifth largest yacht in the world, owned by a billionaire oil tycoon from the UAE. It has also been argued that his traveling causes him to produce a lot more carbon dioxide emissions than most people.

However, this does not mean DiCaprio has not tried to lead a green lifestyle. He owns an apartment in an eco-friendly apartment building in Battery Park City, and drives a Toyota Prius and a Fisker electric sports car. He's been spotted riding a bike around New York, and in 2007 he produced and narrated "The 11^th Hour," a documentary about climate change and other threats to the planet.

Many activists and politicians have realized this and commended DiCaprio for it, including UN Secretary General Ban-Ki Moon. Moon recently appointed DiCaprio to serve as a United Nations Messenger of Peace, and has called the actor "a new voice for climate advocacy."

And now for some of DiCaprio's wise words: "I am not a scientist, but I don't need to be. Because the world's scientific community has spoken, and they have given us our prognosis, if we do not act together, we will surely perish. Now is our moment for action."