National Geographic: Behind all the fanfare around this week’s UN Climate Summit, which will bring 120 heads of state to New York on Tuesday, looms one big question: Will the nations of the world agree on a path to avoid the most dangerous consequences of climate change, such as dramatic sea-level rise and extreme droughts and storms?

The answer will not come during the official summit. This week’s event is not a negotiating session for the next international agreement; that will happen in December 2015, when countries that are signatories to the United Nations Framework Convention on Climate Change meet in Paris.

But it’s looking increasingly likely that the next big international agreement on climate change will not be a legally binding treaty like the 1997 Kyoto Protocol, which required developed countries to reduce greenhouse gases by specific amounts (and which was rejected by the United States and, more recently, Canada).

Nor will the next global climate deal likely require the deep reductions in greenhouse gas emissions that scientists say would be necessary to prevent catastrophic impacts from global warming, according to current and former Obama administration officials and other observers of ongoing international climate negotiations.

There are lots of reasons why a treaty is unlikely, beginning with the near certainty that the U.S. Senate would not ratify one. [Continue reading…]