Our frozen planet is changing. In this final episode, we meet the scientists and people dedicating their lives to understanding what these changes mean, not just for the animals and people who live there, but for the world as a whole.
Our journey begins in the Arctic, where every summer huge quantities of ice calve from the edges of Greenland’s melting glaciers. On top of the ice cap itself, glaciologist Alun Hubbard descends into a moulin to try to understand the mechanisms that are driving this historic loss of ice.
Elsewhere in the Arctic, it’s not just land ice that is disappearing. In the Gulf of St Lawrence, Canada, biologists are trying to find out how the loss of sea ice will impact the lives of baby harps. In Arctic Russia, with the loss of summer sea ice, more and more polar bears are arriving on the island of Wrangel. Here, a local ranger and scientists are braving the hungry bears to assess their future survival.
Loss of sea ice impacts not just wildlife but people too. In the remote community of Qaanaaq, Greenland, local Inuit hunters are finding the ice too dangerous to travel and hunt on, risking their traditional way of life. And these changes happening in the Arctic have the potential to affect people far beyond. On Alaska’s open tundra, bubbling lakes hint at the gases being released from the previously frozen soil, including the potent greenhouse gas methane.
There is one place where the full scale of a melting Arctic can be best witnessed - from space. Based in the International Space Station, astronaut Jessica Meir looks down at forest fires across Europe and reflects how our changing weather patterns are interconnected.
Rapid ice loss is also happening across the high mountains of the planet’s continents. Glaciologist Hamish Pritchard uses a sophisticated helicopter-strung radar system to try to quantify how much ice is left in the previously uncharted glaciers of the Himalayas. It’s important as, downstream, some 1.2 billion people rely on glacial meltwater as their primary source of fresh water.
Finally, in Antarctica, we meet Bill Fraser, who has dedicated 45 years of his life to studying the Adelie penguin. Over this period, he has witnessed changes in weather conditions and the extinction of entire colonies. These ‘canaries in the coal mine’ are a sign that all is not well, even in the remotest place on earth. And changes here have the potential to affect all of us, so an international group of scientists is on an urgent mission to assess the stability of a huge body of ice known as the Thwaites ice shelf. If this plug of ice melts and slips into the ocean, it will raise global sea levels, impacting coastal communities across the planet.
The unprecedented changes our scientists are witnessing may be profound, but there is hope that, through a combination of technology and willpower, there is still time to save what remains of our frozen planet.

A team of intrepid palaeontologists recently discovered a lost world of dinosaurs in the unlikeliest of places — deep in the dark, snowy wilds of northern Alaska. Surprisingly, new findings indicates that dinosaurs thrived year-round and raised their young in frigid and dark conditions in the far north of the Arctic Circle.
Rappelling down giant ice cliffs bordering the Colville River, the team wields chainsaws to extract fossils frozen into the permafrost. Newly found dinosaur tracks indicates that a wide variety of species once flourished there, including herds of duck-bills, horned herbivores, pterosaurs, a new type of velociraptor, and northern relatives of T-rex.

In Southeast Alaska, there's an ice-bound Eden that harbors possibly the richest temperate rainforests of all. Where the coastal mountains meet the Pacific, lays the Alexander Archipelago, a remote island chain running for almost 300 miles along the Alaskan Panhandle. This frozen frontier is one of the last great wildernesses of North America. And a stronghold for the country's highest diversity of megafauna, feasting on the abundance of fleeting summers to make it through relentless winters.

He's the deadliest weapon on the battlefield, but behind enemy lines, what happens when the tables are turned and the hunter becomes the hunted? From the treacherous jungles of Vietnam and the bloody war zones of Iraq, to danger high in the skies of the Alaskan wilderness, this two-hour special puts you behind the scope with the men who pulled the trigger on some of the deadliest missions in military and law enforcement history.
Gripping firsthand accounts, 3-D graphics and jaw-dropping shooting demonstrations take you inside the shadowy world of top snipers and the missions that made them living legends. Outmanned and out-gunned - will the next shot be his last?

Timothy Treadwell's death was as sensational as his life: Having presumed he could live safely among the grizzly bears of the Alaskan wilderness, the outdoorsman and author (Among Grizzlies)--along with his partner, Amie Huguenard--was eventually killed and devoured by one of the very animals to whom he had devoted years of study.
In telling this story, Werner Herzog relies considerably on Treadwell's own video footage, shot during his time in the wild. The famed German director takes Treadwell's story into unexpected emotional frontiers and startling landscapes of the mind. Treadwell is an intriguing, infuriating, perhaps even tragic figure. But Herzog himself is equally compelling, and this brilliant film is just one reason why.

Every summer in the seas off Alaska humpback whales, sea lions and killer whales depend on an explosion of plant life, the plankton bloom. It transforms these seas into the richest on Earth. But will these animals survive to enjoy the great feast? The summer sun sparks the growth of phytoplankton, microscopic floating plants which can bloom in such vast numbers that they eclipse even the Amazon rainforest in sheer abundance of plant life. Remarkably, it is these minute plants that are the basis of all life here. But both whales and sea lions have obstacles to overcome before they can enjoy the feast. Humpback whales migrate 3,000 miles from Hawaii, and during their 3 month voyage lose a third of their body weight. In a heart-rending scene a mother sea lion loses her pup in a violent summer storm, while another dramatic sequence shows a group of killer whales working together to kill a huge male sea lion.
In late summer the plankton bloom is at its height. Vast shoals of herring gather to feed on it, diving birds round the fish up into a bait ball and then a humpback whale roars in to scoop up the entire ball of herring in one huge mouthful. When a dozen whales work together they employ the ultimate method of co-operative fishing - bubble net feeding. One whale blows a ring of bubbles to engulf the fish and then they charge in as one. Filmed from the surface, underwater and, for the first time, from the air, we reveal how these giant hunters can catch a tonne of fish every day.