Earth Report investigates the impact that development has had on the environment and explores what is being done to protect our planet. The Northwest Passage opened for the first time in recorded history, much of the United States honeybee population mysteriously died and China bypassed the United States in total carbon emissions. Despite all of Earths ailments, there are glimmers of hope countries, businesses and individuals making great advances in eco-friendly policies and practices. In Earth Report, National Geographic takes the pulse of our planet and explores what kind of shape Planet Earth is in.

Introduction: Zecharia Sitchin’s The 12th Planet purports to contain “indisputable documentary proof” that all of humanity was created by a group of aliens who visited this planet between roughly 450,000 BC and 13,000 BC. The aliens created humanity by combining their DNA with that of the proto-humans the found on Earth in a scheme to create somewhat intelligent workers for the mining enterprises they were founding on Earth. This work is intended to be an analysis of Sitchin’s book in light of mainstream archeological thought about ancient Sumeria and mainstream science in other fields such as aerospace engineering, astronomy, evolution, Bible research, and so on.

Every plant, microorganism, and animal on Earth exists within an ecosystem: a complex network of interdependent relationships in which each individual strand is important and contributes to the success of the whole. Ecosystems, in turn, interact with one another to form the biosphere: the zone of life on our planet.

A six-part series in which scientists, explorers and others examine unique natural locations around the world and the forces of nature that created them.

The Taiga forest, on the edge of the Arctic, is a silent world of stunted conifers. The trees may be small but filming from the air reveals its true scale. A third of all trees on Earth grow here and during the short summer they produce enough oxygen to change the atmosphere.In California General Sherman, a giant sequoia, is the largest living thing on the planet, ten times the size of a blue whale. The oldest organisms alive are bristlecone pines. At more than 4,000 years old they pre-date the pyramids. But the baobab forests of Madagascar are perhaps the strangest of all.

A humpback whale mother and calf embark on an epic journey from tropical coral paradises to storm ravaged polar seas.Newly discovered coral reefs in Indonesia reveal head-butting pygmy seahorses, flashing 'electric' clams and bands of sea kraits, 30-strong, which hunt in packs. Elsewhere plagues of sea urchins fell forests of giant kelp. Huge bull fur seals attack king penguins, who despite their weight disadvantage, put up a spirited defence.

Jungles cover roughly three per cent of our planet yet contain 50 per cent of the world's species. High-definition cameras enable unprecedented views of animals living on the dark jungle floor.In the Ngogo forest the largest chimpanzee group in the world defends its territory from neighbouring groups. Other jungle specialists include parasitic fungi which infiltrate an insect host, feed on it, and then burst out of its body.

After filming for three years, Planet Earth finally captures the shy Mongolian gazelle. Only a handful of people have witnessed its annual migration. Don't miss the bizarre-looking Tibetan fox, captured on film for the first time.Over six weeks the team follow a pride of 30 lions as they attempt to hunt elephants. Using the latest night vision equipment, the crew film the chaotic battles that ensue at close quarters.

The Arctic and Antarctic experience the most extreme seasons on Earth. Time-lapse cameras watch a colony of emperor penguins, transforming them into a single organism. The film reveals new science about the dynamics of emperor penguin behaviour.In the north, unique aerial images show a polar bear swimming more than 100km. Diving for up to two minutes at a time. The exhausted polar bear later attacks a herd of walrus in a true clash of the Titans.

Around 30% of the land's surface is desert, the most varied of our ecosystems despite the lack of rain. Saharan sandstorms reach nearly a mile high and desert rivers run for a single day.In the Gobi Desert, rare Bactrian camels get moisture from the snow. In the Atacama, guanacos survive by licking dew off cactus spines. The brief blooming of Death Valley triggers a plague of locusts 65km wide and 160km long. A unique aerial voyage over the Namibian desert reveals elephants on a long trek for food and desert lions searching for wandering oryx.

The Cave of Swallows in Mexico is a 400m vertical shaft, deep enough to engulf the Empire State Building. The Lechuguilla cave system in the USA is 193km long with astonishing crystal formations.Caves are remarkable habitats with equally bizarre wildlife. Cave angel fish cling to the walls behind waterfalls with microscopic hooks on their fins. Cave swiftlets navigate by echo-location and build nests out of saliva. The Texas cave salamander has neither eyes nor pigment. Planet Earth gets unique access to a hidden world of stalactites, stalagmites, snotites and troglodytes.

Fresh water defines the distribution of life on land. Follow the descent of rivers from their mountain sources to the sea. Watch spectacular waterfalls, fly inside the Grand Canyon and explore the wildlife in the world's deepest lake.Planet Earth captures unique and dramatic moments of animal behaviour: a showdown between smooth-coated otters and mugger crocodiles; deep-diving long tailed macaques; massive flocks of snow geese on the wing and a piranha frenzy in the perilous waters of the world's largest wetland.

Tour the mightiest mountain ranges, starting with the birth of a mountain at one of the lowest places on Earth and ending at the summit of Everest.One of Earth's rarest phenomena is a lava lake that has been erupting for over 100 years.The same forces built the Simian Mountains where troops of gelada baboons live, nearly a thousand strong. In the Rockies, grizzlies build winter dens inside avalanche-prone slopes. The programme also brings us astounding images of a snow leopard hunting on the Pakistan peaks, a world first.

The lives of animals and plants are dominated by the sun and fresh water which trigger seasonal journeys. The latest technology and aerial photography enable the Planet Earth team to track some of the greatest mass migrations.In the Arctic spring, a mother polar bear and cubs emerge from their winter den. They have just two weeks to cross the frozen sea before it melts and they become stranded. Share the most intimate and complete picture of polar bear life ever filmed. Further south, time-lapse cameras capture the annual transformation created by the Okavango floods.

The sixth programme looks at the regions of the Arctic and Antarctica. The latter contains 90% of the world's ice, and stays largely deserted until the spring, when visitors arrive to harvest its waters. Snow petrels take their place on nunataks and begin to court, but are preyed on by South Polar skuas. During summer, a pod of humpback whales hunt krill by creating a spiralling net of bubbles. The onset of winter sees the journey of emperor penguins to their breeding grounds, 160 kilometres (99 mi) inland. Their eggs transferred to the males for safekeeping, the females return to the ocean while their partners huddle into large groups to endure the extreme cold.

The penultimate episode surveys the coniferous and deciduous seasonal woodland habitats — the most extensive forests on Earth. Conifers begin sparsely in the Arctic but soon dominate the land, and the taiga circles the globe, containing a third of all the Earth's trees. Few creatures can survive the Arctic climate all year round, but the moose and wolverine are exceptions. 1,600 kilometres (990 mi) to the south, on the Pacific coast of North America, conifers have reached their full potential.

This programme is devoted to the shallow seas that fringe the world's continents. Although they constitute 8% of the oceans, they contain most marine life. As humpback whales return to breeding grounds in the tropics, a mother and its calf are followed. While the latter takes in up to 500 litres of milk a day, its parent will starve until it travels back to the poles to feed — and it must do this while it still has sufficient energy left for the journey. The coral reefs of Indonesia are home to the biggest variety of ocean dwellers.