Harrison Ford continues his investigation into the global effects of the palm oil industry, exploring the corruption that has deforested the Indonesian landscape and created the world's largest emitter of greenhouse gases. Meanwhile, Former Governor Arnold Schwarzenegger joins an elite team of wild-land firefighters known as "Hot Shots" as they battle a new breed of forest fires made more deadly by climate change, and discovers another killer wiping out trees at an even faster rate than the fires.

MSNBC's Chris Hayes shadows Staten Island's Republican Congressman - and climate change skeptic - Michael Grimm in the wake of Superstorm Sandy, questioning what he might have learned about climate change in the process. Conservationist M. Sanjayan travels to the far ends of the earth - including Christmas Island - to interview some of the world's top climate scientists as they collect key data unlocking the future of our planet's changing climate.

Lesley Stahl of '60 Minutes' travels to Greenland to investigate the effects of global warming in the Arctic. Down south, Ian Somerhalder travels to North Carolina to listen in on both sides of the evangelical community's debate over climate change and finds himself caught in the middle of not only a religious debate, but a familial one: the father is a megachurch preacher who doesn't believe in climate change; the daughter is an activist trying to shut down the local coal-fired power plant.

Olivia Munn profiles climate-conscious Governor Jay Inslee of Washington State, discussing the issues he's faced since being elected. Meanwhile, 'New York Times' columnist Mark Bittman probes New Jersey Governor Chris Christie on the topic of man-made climate change during the rebuilding of his state's coastline in the aftermath of Superstorm Sandy. Christie once acknowledged the scientific consensus on climate change, but steadfastly refused to discuss it during the rush to rebuild.

America Ferrera profiles prominent skeptic James Taylor of the Heartland Institute as he crusades against clean energy, and investigates the battle over the future of renewable energy in the US. 'New York Times' columnist Mark Bittman returns to conduct a yearlong investigation into natural gas, which has been touted as "America's energy source" and a way towards a cleaner, greener future. But is it true?

Jessica Alba meets three members of Climate Corps - an innovative MBA-focused program - as they try to convince America's corporations that sustainability can actually boost their bottom lines. Pulitzer Prize-winner Thomas L. Friedman finds himself in Egypt to explore how what happens in the wheat fields of Kansas plays out on the volatile streets of Cairo. And MSNBC's Chris Hayes reveals an intimate story about life after Superstorm Sandy, with the most economically vulnerable trying to survive the impacts of climate change.

Matt Damon investigates the impact of extreme heat on human health and mortality, with a focus on research that has uncovered how rising temperatures are creating a worldwide public health emergency. Michael C. Hall visits Bangladesh to explore the prediction that by 2050, a global migration of upwards of 150 million people will produce the single most daunting burden to our future. And Thomas L. Friedman travels to Yemen to conclude his look into how climate stress can push volatile political situations over the edge.

Michael C. Hall concludes his journey to the low-lying country of Bangladesh, where rising seas are expected to ultimately submerge 17% of the nation. Conservationist M. Sanjayan returns to further question some of the world's top climate scientists as they collect key data unlocking the past and future of our planet's changing climate. His destination: Tupungatito, the northernmost historically active stratovolcano in the southern Andes. Series finale.