As the Earth's average temperature rises each year, experts warn that we are nearing a fatal tipping point, 2 degrees Celsius above the norm, that will set into motion a cascade of natural disasters that will devastate America and the world. From raging fires to epic superstorms, volcanic blasts and rising seas, will human existence be pushed to the brink?

The Marianas Trench is the deepest place on earth, deeper than Mt. Everest is high. The trench is where the ocean floor disappears into the center of the earth. The pressures at this depth are 17 times greater than what it takes to crush a nuclear submarine. Only two men have ever been down the Trench, fewer than have set foot on the moon. Follow the daring missions into the abyss, and explore the extraordinary geology that has created this deep scar along the ocean floor.

The Atacama desert is considered the driest place on Earth. Since human records of the area began, some places have never received rain. But the records don't stop there--the Atacama is also the oldest desert in the world, and recently it has been dated to an amazing 150 million years old. Other research shows that the surface of this desert is also incredibly ancient, with boulders lying there that have not moved for over 23 million years--more than 50 times longer than it's taken for our human species to evolve. The soil is so dry, it has been used as a test bed for the Mars rovers. And though the desert was once thought to be completely lifeless, strange bacteria discovered there have given scientists new hope that they might find life on the red planet. Atacama is also home to the largest copper mine in the world. Inspect the riddle of the Atacama, and uncover how this extraordinarily dry landscape was created.

In the remote wastes of Siberia buried under snow are the remains of one of the greatest catastrophes that the Earth has endured. 250 million years ago, huge volumes of lava spewed out onto the surface--so much that it would have buried the whole of Texas under one mile of lava. At first the temperature dipped, but then the greenhouse gases that escaped from the depressurized lava caused a massive global warming. It wreaked havoc, and 95% of the species on Earth became extinct. Yet life hung on, and in time this disaster paved the way for the next great phase of life on earth--the age of the dinosaurs.

Over 20 years ago, Mt. St Helens--thought to be dormant--shocked America when it exploded. It is an acidic volcano--the magma beneath is full of volatiles, making it highly explosive. A new plug has formed in its throat and is rising.

Mt Vesuvius is the world's most dangerous volcano, and it threatens three million people. It was responsible for the most famous natural disaster of ancient history.

On August 27th, 1883, a series of blasts on the island of Krakatoa culminated in a colossal explosion that blew the island apart in one of the largest eruptions in recorded history.