Having explained the science behind global warming, and addressed the arguments of the climate change sceptics earlier in the series, Dr Iain Stewart concludes the series by looking at the biggest challenge now facing climate scientists - Just how can they predict exactly what changes global warming will bring?
It's a journey that takes him from early attempts to model the climate system with dishpans, to supercomputers, and to the frontline of climate research today: Greenland. Most worryingly he discovers that scientists are becoming increasingly concerned that their models are actually underestimating the speed of changes already underway.

Our blue planet is facing one its biggest threats in human history. Trillions of pieces of plastic are choking the very lifeblood of our earth, and every marine animal, from the smallest plankton to the largest mammals, is being affected. But can we turn back this growing plastic tide before it is too late? Wildlife biologist Liz Bonnin visits scientists working at the cutting edge of plastics research. She works with some of the world's leading marine biologists and campaigners to discover the true dangers of plastic in our oceans and what it means for the future of all life on our planet, including us.
Liz travels to a remote island off the coast of Australia that is the nesting site for a population of seabirds called flesh-footed shearwaters. Newly hatched chicks are unable to regurgitate effectively, so they are filling up on deadly plastic. She visits the Coral Triangle that stretches from Papua New Guinea to the Solomon Islands to find out more from top coral scientists trying to work out why plastic is so lethal to the reefs, fragile ecosystems that contain 25 per cent of all marine life.

Dr Janina Ramirez shows how medieval manuscripts gave power to the king and united the kingdom in an age of plague, warfare and rebellion, discovers that Edward III used the manuscripts he read as a boy to prepare him for his great victory at the battle of Crecy and reveals how a vigorous new national identity bloomed during the 100 Years War with France. In the British Library's Royal Manuscripts collection Dr Ramirez finds out that magnificent manuscripts like the Bedford Hours, taken as war booty from the French royal family, were adapted for the education of English princes. She also explores how knowledge spread through a new form of book - the encyclopaedia.

Dr Iain Stewart investigates the counter-attack that was launched by the global warming sceptics in the 1990s. At the start of the 1990s it seemed the world was united. At the Rio Earth summit the world signed up to a programme of action to start tackling climate change. Even George Bush was there. But the consensus didn't last.
Iain examines the scientific arguments that developed as the global warming sceptics took on the climate change consensus. The sceptics attacked almost everything that scientists held to be true. They argued that the planet wasn't warming up, that even if it was it was nothing unusual, and certainly whatever was happening to the climate was nothing to do with human emissions of greenhouse gases. Iain interviews some of the key global warming sceptics, and discovers how their positions have changed over time.

A feature documentary about the world-famous magician, escape artist, and world-renowned enemy of deception, James 'The Amazing' Randi. The film brings to life Randi's intricate investigations that publicly exposed psychics, faith healers, and con-artists with quasi-religious fervour. A master deceiver who came out of the closet at the age of 81, Randi created fictional characters, fake psychics, and even turned his partner of 25 years, the artist Jose Alvarez, into a sham guru named Carlos. But when a shocking revelation in Randi's personal life is discovered, it isn't clear whether Randi is still the deceiver - or the deceived.

About 340 million years ago a brand new family of animals was evolving in the primeval swamps. They were to go one step further than the amphibians who had emerged onto dry and before them. For they would eventually completely cut their ties with water. They were the ancestors of todays lizards. They evolved scaly impermeable skins and moved up into the forests. They diversified into a multitude of different shapes and sizes. They developed signalling systems to communicate with one another. And they squabbled as animals do. For food they hunted insects that were already well established on the land in great numbers. And here without returning to water they produced their families. They powered their bodies not only with food but with the heat that they drew directly from the sun.
As they diversified so they spread into the harshest of the lands habitats. The baking waterless deserts which eventually they would come to dominate. Discover jacky lizards that wave, wrestling beaded lizards and the the world's smallest chameleon, which is no bigger than his thumbnail, and the biggest lizard in Australia.