Welcome to the briefing room with me, David Aronovich.

Step inside and find out what you need to know about the issues that matter from people who really know what they're talking about.

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This week, we're talking about climate change, and I'll be speaking to Lord Nicholas Stern, who back in 2006, was author of the very influential Stern review on climate change.

And if you enjoy this podcast, you might enjoy other editions of the briefing room,

which are all available on BBC Sounds.

Right now, we're facing a man-made disaster of global scale.

Our greatest threat in thousands of years, climate change.

Arguably, it's the most important story of them all.

In October, the IPCC, that's the UN body that reports on climate change,

issued a report that concluded that if humanity wants to avoid catastrophic environmental damage,

then we need to reduce carbon emissions by almost half in the next 12 years. 12. And that would

mean, and I quote, rapid, far-reaching and unprecedented changes in all

aspects of society. What things would we have to do and what are the chances of us doing them?

It's a huge subject, but you can make a start here with me in the briefing room.

First, a word about our assumptions. This program is predicated on the acceptance

that the international scientific consensus on climate change

and its causes is more likely than not to be correct.

Just so you know. First, we're going to get a

brief history of climate change from Professor Mark Maslin. He's a climatologist at University

...