Hundreds of world leaders are descending on the United Nations for a one day meeting on climate change. This is a big deal for the United Nations, for diplomacy, and possibly for the planet. So who is showing up and what countries are snubbing the conference? What will be discussed? And how will this affect ongoing negotiations to construct an internationally binding climate change agreement? Mark speaks with Elliot Diringer of the Center for Climate and Energy Solutions who helps put this historic meeting at the United Nations in the larger context of international climate change diplomacy. This is a very useful conversation for understanding the diplomatic contours of arguably the single most important issue facing humanity today.