This week on the show that brings you the science behind the news, we’re looking at news that China’s population has fallen for the second year running. Worrying news for China’s economy, but would a declining population be a good thing for the planet?

The Unexpected Elements team on three continents meet the musical frogs who are having to climb a mountain to keep their populations stable, and dig deep to explore the earth’s declining microbiome and the hope scientists have for the future.

As the Africa Cup of Nations continues, we’ll be wondering how you might date a footballer. Not in a romantic sense… we hear about some suspiciously mature youth players and how science can help when the age on a passport isn’t reliable.

Marnie will be wondering why Japanese men are shouting their love from a hilltop, and unpicking the recipe for a truly satisfying hug.

All that plus a postbag bursting with multilingual puns, and the reason Portuguese speakers have trouble with English doors.

Presented by Marnie ChestertonProduced by Ben Motley, with Alex Mansfield, Dan Welsh, Katy Tomsett and Jack Lee