1.5C.

It’s THE number we talk about when we talk about climate change.

But what does 1.5C actually mean now – and as the world saw record-breaking heat last year, does it even matter anymore?

Climate scientist Mark Maslin and environmental psychologist Lorraine Whitmarsh discuss.

Also this week, new clues about how life may have begun from a dusty space rock called Bennu, and New Scientist’s Graham Lawton brings us the science of the week, including AI’s ‘Sputnik moment’, the mice born with two fathers, and how often do unexpected discoveries happen?

Presenter: Victoria Gill Producers: Sophie Ormiston, Ella Hubber & Gerry Holt Editor: Martin Smith Production Co-ordinator: Jana Bennett-Holesworth 

If you want to test your climate change knowledge, head to bbc.co.uk search for BBC Inside Science and follow the links to The Open University to take the quiz.