Earth: The Power Of The Planet Ep5 (bbc)

Description: "Earth: The Power of the Planet" highlights the major events which have shaped the Earth’s history and allowed life to flourish. Presented by Dr Iain Stewart, each episode will reveal a different force critical to the development of Earth including volcanoes, the ocean, the atmosphere and ice. The series follows Dr Stewart’s personal journey to some of the most remote places on the planet, from abseiling down into a lava lake in Ethiopia to cave diving in the underwater caverns left by the impact of the meteorite that wiped out the dinosaurs. He will discover how volcanoes saved the planet, how a rainstorm lasted for thousands of years, and how the Mediterranean Sea once dried up. Each individual film highlights the delicate balance of life on Earth, and how its incredible history has been the story of disaster and recovery. Volcano Volcanoes are one of nature's most awesome and destructive forces, but they are also the life force and architect of our planet. They can raise up great mountains and create new land, or they can level cities and destroy entire civilizations. They provide a glimpse of the power of Earth's internal heat source, without which it would have become a dead planet millions of years ago. In this episode, Iain takes us on a journey to some of the most dramatic places on Earth, starting in Ethiopia. Atmosphere The atmosphere is Earth's protective layer, cloaking us in a warm, oxygen-rich embrace and shielding us from the cold hostility of space. It acts as a natural greenhouse, keeping the Earth 51 degrees Fahrenheit warmer than it would otherwise be. Yet the atmosphere is also full of contradictions. It's immensely powerful but at the same time highly sensitive. It's destructive, yet it shelters us. It was created in part by the planet's first organisms, and it continues to be essential for life.