Oceans are the largest ecosystem on earth, covering two thirds of our world’s surface and providing half the oxygen in our atmosphere. They are home to as much as 80 per cent of all life on earth, and nearly three billion people rely on them for their primary source of food.
But our planet’s oceans would be little more than stagnant wastelands, and life on planet earth would cease to exist, were it not for one simple factor: a global network of powerful ocean currents. Every drop of seawater on earth rides these currents, taking 1,000 years to complete a single circuit. Without the constant mixing of currents, tides and waves, our oceans would stop supporting life - and a healthy ocean is vital to a healthy planet.

A new force threatens our perfect planet. In the past, five mass extinction events were caused by cataclysmic volcanic eruptions. It was not the lava or ash that wiped out life, but an invisible gas released by volcanoes: carbon dioxide. Almost every part of modern life depends on energy created by burning fossil fuels, and this produces CO2 in huge amounts. Humans are changing our planet so rapidly, it’s affecting earth’s life support systems: our weather, our oceans and the living world. The greatest change to be made is in how we create energy, and the planet is brimming with natural power that can help us do just that. It’s these forces of nature - the wind, the sun, waves and geothermal energy - that hold the key to our future.
Through compelling animal-led stories and expert interviews, we discover how CO2 is destabilising our planet. We meet rescued orphaned elephants in Kenya, victims of ever worsening droughts, and join ocean patrols off the coast of Gabon fighting to save endangered sharks. In the Amazon, we witness wildlife teams saving animals in the shrinking forests, and in San Diego we enter a cryogenic zoo preserving the DNA of endangered species before they become extinct.

Uranus and Neptune, two of the largest, farthest and strangest planets in our solar system. These two planets break all the rules. Of all the big planets, Uranus and Neptune remain the biggest enigmas. Today, astronomers are finally unlocking why these supersized snowballs are so weird. Can an ancient mega-collision reveal what knocked Uranus onto its side? Can a missing twin world unlock why one of Neptune's moons orbits the wrong way? And what is the energy that drives the fastest winds in the solar system?

To survive Mars, our species will need to evolve how we eat, drink, and build our homes. Will we need our genes to evolve as well? Sometime in the future humans will leave Earth to colonize Mars, and in doing so will begin to adapt to life on another planet in surprising ways. Evolutionary biologist Dr. Scott Solomon foresees a series of changes to our species from the size of our hearts and heads to the pigments in our skin.

Science may soon make the dream of traveling to Mars a reality, but how will we live once we get there? How will we manage our basic human needs of food, water, and shelter on a planet known for its barren surface conditions, high radiation levels, and toxic dirt?

The Namib Desert is one of the oldest deserts and also one of the most diverse. With 50ºC (120ºF) temperatures and half a millimetre of rainfall annually, we see how this is possible. Half the size of Oklahoma, from its Skeleton Coast through the sea of sand to the haze of distant mountains this apparently forbidding desert hides secret water sources.