Series exploring topical scientific issues. Horizon follows the climate researchers investigating the strange patterns of severe weather seen around the world in recent years.

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 what is to come.