Climate Change By Numbers

Confirmed for BBC Four on 2 March at 9pm to 10.15pm

Monday 2 March



At the heart of the climate-change debate is a paradox: we've never had more information about our changing climate, but surveys show that the public are, if anything, getting less sure they understand what’s going on.

This 75-minute special for BBC Four aims to remedy that, with a new perspective on the whole subject. Presented by three mathematicians – Dr Hannah Fry, Prof Norman Fenton and Prof David Spiegelhalter – it hones in on just three key numbers that clarify all the important questions around climate change. The stories behind these numbers involve an extraordinary cast of characters, almost all of who had nothing to do with climate change, but whose work is nevertheless critical to our understanding of the climate.

The three numbers are:

  • 0.85 degrees (the amount of warming the planet has undergone since 1880)
  • 95% (the degree of certainty climate scientists have that at least half the recent warming is man-made), 
  • 1 trillion tonnes (the total amount of carbon we can afford to burn – ever – in order to stay below ‘dangerous levels’ of climate change)

Understanding how scientists came up with these three numbers gives a unique perspective on what we know about the past, present and future of our changing climate. But it also takes us on a journey through how science is conducted, to the very limits of what science can tell us.