Climate activists have written a letter to UN climate leaders demanding that big oil lobbyists be banned from the annual COP climate meetings. This year's U.N. climate summit is struggling to focus minds on the health of the planet, with turbulent geopolitics, a confrontational host and the reelection of U.S. climate skeptic Donald Trump stealing the limelight. We talk with correspondent in Chermaine Lee, who is at the conference in Azerbaijan.