Something weird seems to be happening to our weather - it appears to be getting more extreme. In the past few years we have shivered through two record-breaking cold winters and parts of the country have experienced intense droughts and torrential floods. It is a pattern that appears to be playing out across the globe. Hurricane chasers are recording bigger storms and in Texas, record-breaking rain has been followed by record-breaking drought. Horizon follows the scientists who are trying to understand what's been happening to our weather and investigates if these extremes are a taste of whats to come.

A&E doctor Kevin Fong finds out how doctors can avoid making mistakes in the high-pressure, high-stakes world of the operating theatre.

He sets out to learn how other professionals make life and death decisions under pressure, from airline pilots facing emergencies, to the Fire Service dealing with lethal blazes, to the world of Formula One pit crews. Kevin discovers how all these fields are helping to make surgery safer.

What's worse for us: sugar or fat?

To answer the hottest question in nutrition, twin doctors Chris and Xand Van Tulleken go on month long high-fat and high-sugar diets. The effects on their bodies are shocking and surprising.

But they also discover that in the debate about fat and sugar, the real enemy might have been hiding in plain sight.

The oceans define the earth. They are crucial to life and we used to think that they were unique to our blue planet. But we were wrong.

It has recently been discovered that there are oceans all over our solar system and they are very similar to our own. And now scientists are going on an epic journey in search of new life in places that never seemed possible. Nasa is even planning to dive to the depths of a strange, distant ocean in a remarkable submarine.

Horizon discovers that the hunt for oceans in space is marking the dawn of a new era in the search for alien life.