Sir David Attenborough journeys to both Polar Regions to investigate what rising temperatures will mean for the people and wildlife that live there and for the rest of the planet. David starts out at the North Pole, standing on sea ice several metres thick, but which scientists predict could be Open Ocean within the next few decades. The Arctic has been warming at twice the global average, so David heads out with a Norwegian team to see what this means for polar bears. He comes face-to-face with a tranquilised female, and discovers that mothers and cubs are going hungry as the sea ice on which they hunt disappears. In Canada, Inuit hunters have seen with their own eyes what scientists have seen from space; the Arctic Ocean has lost 30% of its summer ice cover over the last 30 years. For some, the melting sea ice will allow access to trillions of dollars worth of oil, gas and minerals. For the rest of us, it means the planet will get warmer, as sea ice is important to reflect back the sun's energy. Next David travels to see what's happening to the ice on land: in Greenland, we follow intrepid ice scientists as they study giant waterfalls of meltwater, which are accelerating iceberg calving events, and ultimately leading to a rise in global sea level. Temperatures have also risen in the Antarctic - David returns to glaciers photographed by the Shackleton expedition and reveals a dramatic retreat over the past century. It's not just the ice that is changing - ice-loving adelie penguins are disappearing, and more temperate gentoo penguins are moving in. Finally, we see the first ever images of the largest recent natural event on our planet - the break up of the Wilkins Ice Shelf, an ice sheet the size of Jamaica, which shattered into hundreds of icebergs in 2009.

Rivers provide the essentials of life: fresh food and water. They often provide natural highways and enable us to live in just about every environment on Earth. But rivers can also flood, freeze or disappear altogether!Cities - Surviving the Urban Jungle Human Planet joins Sam Niang, a Laotian fisherman, as he walks a high wire strung above the raging Mekong River rapids on an extraordinary commute to work. There's also a look at the remarkable partnership between Samburu tribesmen and wild elephants in their search for water in the dried-out river beds of Northern Kenya. Plus, a father who must take his two children on a six-day trek down a frozen river - the most dangerous school run on Earth, and the ice dam busters of Ottowa with their dynamite solution to a city centre hold-up.

A visually stunning journey to the end of the world with the hardy and devoted people who live there year-round. The research stations scattered throughout the continent host a close-knit international population of scientists, technicians and craftsmen. Isolated from the rest of the world, enduring months of unending darkness followed by periods when the sun never sets, Antarctic residents experience firsthand the beauty and brutality of the most severe environment on Earth. Capturing epic battles against hellacious storms, quiet reveries of nature's grandeur, and everyday moments of work and laughter, this unique documentary shows a steadfast community thriving in a land few humans have experienced. Using specially modified cameras and spectacular time-lapse photography, filmmaker Anthony Powell captures the splendor of the region like no film before. ANTARCTICA: A YEAR ON ICE gives testament to the planet's natural wonders, humanity's thirst for adventure, and the emotional extremes that accompany a year within the last pristine wilderness on the planet.

'Deliver Us from Drought' - Over the past years, Texas has experienced the worst drought in its recorded history. 97% of the scientific community agrees that human activity has contributed to extreme weather patterns around the world. But many Texans--legislators, community leaders and citizens--don't attribute their drought to humans, and have taken few if any initiatives to limit the state's CO2 emissions, currently the highest in the country. "The Resource Curse" - As humanity's appetite for energy grows exponentially, the extraction industry scrambles to the most remote regions on Earth. In the undeveloped Melanesian country of Papua New Guinea, America's Exxon Mobil has staked its claim to a $19 billion liquid natural-gas project. While some see Exxon's mammoth presence as the catalyst that will usher the underdeveloped country into the 21st Century, others predict the initiative could plunge its people into civil war.

'Just Do It: A Tale of Modern-day Outlaws' lifts the lid on climate activism and the daring troublemakers who have crossed the line to become modern-day outlaws. Documented over a year, Emily James' film follows these activists as they blockade factories, attack coal power stations and glue themselves to the trading floors of international banks despite the very real threat of arrest.

Fourth episode examines how plants either share environments harmoniously or compete for dominance within them. Attenborough highlights the 1987 hurricane and the devastation it caused. However, for some species, it was that opportunity for which they had lain dormant for many years. The space left by uprooted trees is soon filled by others who move relatively swiftly towards the light. The oak is one of the strongest and longest-lived, and other, lesser plants nearby must wait until the spring to flourish before the light above is extinguished by leaves. Tropical forests are green throughout the year, so brute force is needed for a successful climb to the top of the canopy: the rattan is an example that has the longest stem of any plant. As its name suggests, the strangler fig 'throttles' its host by growing around it and cutting off essential water and light. Some can take advantage of a fallen tree by setting down roots on the now horizontal trunk and getting nutriment from the surrounding moss and the fungi on the dead bark. The mountain ash (eucalyptus regnans) grows so tall, that regeneration becomes a considerable problem. It is easily flammable, so its solution is to shed its seeds during a forest fire and sacrifice itself. It therefore relies on the periodic near-destruction of its surroundings in order to survive. Attenborough observes that catastrophes such as fire and drought, while initially detrimental to wildlife, eventually allow for deserted habitats to be reborn.