What Will Happen at Today's UN Climate Summit? 125 world leaders convene in NYC to rally for new climate initiatives By Jenn Gidman, Newser Staff Posted Sep 23, 2014 7:40 AM CDT 16 comments Comments Smoke emits from chimneys of numerous brick kilns on the outskirts of New Delhi, India, on Sept. 23, 2014. (AP Photo/Altaf Qadri) (Newser) – Today's UN climate summit in New York City will draw together 125 nations in a massive, one-day precursor to Paris talks next year aimed at an overarching agreement, and UN Secretary-General Ban Ki-moon is calling on world leaders to show up with "pledges of action," the BBC reports. The summit was preceded by a thousands-strong climate change march in Manhattan on Sunday, including such high-profile advocates as Mark Ruffalo and Evangeline Lilly; Leonardo DiCaprio is scheduled to give one of this morning's speeches, the Washington Post reports. So what could mar this momentous day? Observers are still wary after Copenhagen's failed summit five years ago, and there are signs of trouble once more. For one, some pretty important players will be no-shows: Chinese President Xi Jinping and Indian Prime Minister Narendra Modi won't be there. The Post notes that together, their countries make up a third of the world's population and rank first and third, respectively, among the biggest carbon-dioxide emissions producers—the US ranks second. Plus, Modi has in the past indicated a willingness to bow down and "live with nature rather than battle it." There've also been relatively sparse donations to the Green Climate Fund, a stash designed to help poorer countries fight pollution, the New Republic reports. Still, Ban is hopeful. "Climate change is a defining issue of our time, and there is no time to lose," he tells the Post. "There is no Plan B because we do not have Planet B."