David Letterman travels to India where the government has committed to one of the most ambitious renewable energy plans on Earth.

Miami could be underwater by the end of the century if nothing is done to curb emissions. Jack Black investigates whether the city can survive the rising seas, while Ian Somerhalder takes an ocean voyage in search of clues from the past to understand hurricanes of the future. Diving into "blue holes," he shows how we're heating the oceans up. And this could mean giant storms for places like Miami.

New York Times columnist Tom Friedman investigates the increasing population of climate refugees and actor Don Cheadle is on the ground in California, where the worst drought in 1,200 years is having devastating effects.

Executive producer Arnold Schwarzenegger sets out to explore the military's relationship with a changing climate and supermodel and activist Gisele Bündchen travels to her home country of Brazil to explore the devastating decline of the country's forests, much of which is caused by cattle ranching.

Joshua Jackson travels to the Philippines and Australia's Great Barrier Reef to investigate the impacts of climate change on our world's oceans and the millions of people who rely on their ecosystems for their livelihood.

Actress and activist Nikki Reed explores what some believe to be the ultimate solution for climate change: putting a price on carbon. Former "Daily Show" correspondent Aasif Mandvi sets off on a quest to understand just how much of a threat climate change poses to endangered species. He travels to Kenya's wildlife preserves to meet the people on the front lines of conservation efforts.

Ty Burrell explores electric and automated vehicles; Bradley Whitford tackles climate change and politics.

Burning coal remains a major source of energy, emitting toxic pollutants and climate-altering carbon dioxide. In Illinois, America Ferrera meets with activists who want to shut down a local coal plant, and with a mayor who want to keep it open. She learns about an option that can provide clean energy and green jobs. Sigourney Weaver investigates China's impact on on today's global environment, and the progress it is making to reduce emissions even as its economy grows.