US President Barack Obama speaks at the Global Leadership in the Arctic: Cooperation, Innovation, Engagement and Resilience (GLACIER) Conference in the Denaina Civic and Convention Center on August 31, 2015 in Anchorage, Alaska. US President Barack Obama warned that climate change is no longer a problem of the future, but rather a challenge for now and one that will define the next century. AFP PHOTO/ MANDEL NGAN (Photo credit should read MANDEL NGAN/AFP/Getty Images)
