Addressing world leaders earlier today, Obama stressed the urgency of coming together on a deal and raised the deflating prospect of a deal.
"While the reality of climate change is not in doubt, I have to be honest, I think our ability to take collective action is in doubt right now and it hangs in the balance," Obama said at a plenary session at the United Nations summit.
"This is not a perfect agreement, and no country would get everything that it wants," the president said. "But here is the bottom line: we can embrace this accord, take a substantial step forward, and continue to refine it and build upon its foundation. We can do that, and everyone who is in this room will be a part of an historic endeavor, one that makes life better for our children and grandchildren."
Obama outlined three key elements that must be in the final agreement. First, all major economies must commit to reducing their emissions. Second, there must be a transparent review to ensure nations are keeping their commitments to reduce emissions, and thirdly, there needs to be financing to help developing nations adapt to these new standards.
What world leaders do agree on are the stakes. With unprecedented urgency, a chorus of leaders have delivered the same warning -- the planet is already damaged by climate change and countries need to step up to confront this challenge.
"We have a moral obligation towards future generations," said Prime Minister of Denmark Lars Lokke Rasmussen.
UK Prime Minister Gordon Brown described the stake in apocalyptic terms Thursday.
"Without common action, extreme temperatures will create a new generation of poor with climate change refugees driven from their homes by drought, climate change evacuees fleeing the threat of drowning, the climate change hungry desperate for lack of food," Brown said. "Hurricanes, floods, typhoons and droughts that were once all regarded as the acts of an invisible god are now revealed to be also the visible acts of man."
ABC News' Karen Travers, Kirit Radia and Viviana Hurtado contributed to this report.