Iain Stewart travels into the stratosphere on one of the world's fastest aircrafts to examine the atmosphere's dynamic power. Also: a look at methane beneath Siberia's ice-covered ground examines how it could lead to a climate disaster.
A look at how ice carves landscapes, unleashes catastrophes and triggers global climate changes that play a role in human evolution. Spots visited include the French Alps, Yosemite National Park, Antarctica's Lake Vostok and Manhattan.
In the series opener, host Iain Stewart explores the incredible power of volcanoes in some of the planet's most dramatic locations, including Ethiopia's Erta Ale volcano and the volcanic hot springs in Rotorua, New Zealand.