WHO: 31-year-old Arsenal midfielder trying to halt climate change.

WHY: Modern footballers might be hideously overpaid, but at least Mathieu Flamini is investing his millions to try and save the world. In 2008 he became co-founder of geo-energy company GF Biochemicals along with his friend and business partner, Pasquale Granata. Over the last seven years, they’ve invested millions into the hopes of producing levulinic acid – a synthetic oil substitute made from wood and corn waste – on a commercial scale. Their company was the first to discover a way to mass-produce the acid, meaning it can now be used to replace oil in the manufacture of pharmaceuticals, plastics, cosmetics and more.

Until this winter, though, Flamini kept his involvement in the company a secret from everyone, including his friends and family. Not even his teammates or Arsenal boss Arsene Wenger knew about his enterprising sideline.

While the cynical might view the footballer’s involvement as a money-making opportunity, Flamini says he’s always had an interest in environmental issues, having grown up “close to nature” on the Mediterranean island of Corsica. “I’m trying to give my contribution to climate change,” Flamini modestly states of his personal goals.

WHAT HE SAYS: “So many people tried and failed before so why did we succeed? It’s about believing.”

WHAT PEOPLE SAY ABOUT HIM: “Mathieu is a fighter and a winner.” – Arsene Wenger

HOW HE MADE THE WORLD A BETTER PLACE: If Flamini’s technology takes off, it could help reduce our reliance on depleting fossil resources.

Read about why we picked the rest of our People of the Year 2015:

Taylor Swift – For establishing herself as the most powerful pop star on the planet
Kendrick Lamar – For making rap righteous again
The Libertines – For the year’s most beautiful (and unlikely) comeback
Mhairi Black – For changing the face of British politics
Skepta – For taking grime global
Miley Cyrus – For refusing to conform, and celebrating diversity
Nicki Minaj – For speaking out on race, gender and sexuality
Adele – For breaking every record in music history
Jennifer Lawrence – For being the year’s best role model
JJ Abrams – For re-awakening The Force
Noel Gallagher – For cutting through the crap and making us laugh