Earth: The Power of the Planet - Volcano

Documentary series. Dr Iain Stewart reveals the role natural forces have played in the creation of the planet Earth, beginning with volcanoes. Although they are destructive, volcanoes were crucial to the development of life on our planet. Iain's journey takes him to Ethiopia to discover lava lakes, to Iceland to scuba dive between continents, and to New Zealand to sample hot springs. But it's not just a holiday for Dr Stewart: he has a serious point to make. In perhaps the most extraordinary twist of all, volcanoes and life have formed a partnership. Life removes carbon dioxide from the atmosphere, and when it dies and falls to the sea floor it becomes rock which eventually gets buried. After millions of years it is erupted in volcanoes, returning the carbon dioxide to the atmosphere. This long, slow cycle keeps the planet the right temperature for life. The Earth's inner heat shapes our world. It raises up great mountains, it levels cities, it creates new land and destroys it too. It powers the evolution of life on Earth and helps maintain the temperature of the planet. Without it the Earth would have become a dead planet millions of years ago.