The Latest on the high-level U.N. General Assembly meetings (all times local):

9:00 a.m.

U.N. officials say at least 20 countries are expected to formally join the Paris Agreement on climate change this week, greatly improving the pact's chances of coming into force just a year after it was negotiated.

That's considered a blistering pace in the world of international diplomacy, reflecting a sense of urgency in the fight against global warming and a desire to seal the deal before the Obama administration leaves office.

Brazil, Mexico, Argentina and Morocco are expected to hand over documents at the U.N. in New York on Wednesday to formally complete the ratification process. At least half a dozen small island nations including Papua New Guinea, Tonga and Kiribati will also follow suit.

___

8:45

Standing before the United Nations for the last time as president, Barack Obama will reassure foreign leaders that the world is better equipped to tackle its challenges than at almost any point in history despite a cascade of harrowing crises that seem devoid of viable solutions.

Obama's address marks his swan song on the international stage. He stepped into his role eight years ago with sky-high expectations and has struggled to deliver when it comes to solving global problems partially beyond America's control.

Ben Rhodes, Obama's deputy national security adviser, said the president was cognizant of the fact that bright spots such as economic growth and climate change cooperation are offset by the "great deal of unease" in the world, including Syria's civil war and concerns about Russia's aggression toward Ukraine.