Tourists walk on the Perito Moreno Glacier at Los Glaciares National Park, near El Calafate, Argentina, Tuesday, Nov. 2, 2021. World leaders are gathered in Scotland at a United Nations climate summit, known as COP26, to push nations to ratchet up their efforts to curb climate change. Experts say the amount of energy unleashed by planetary warming could melt much of the planet's ice, raise global sea levels and increase extreme weather events. (AP Photo/Natacha Pisarenko)