“To make a hamburger – just one burger – takes what to make?” Mathieu Flamini, elite footballer turned biochemical entrepreneur, asks the question. The answer, it turns out, is 2,000 litres of water. “Insane,” he says. The passion, the elan previously shown in midfield for Marseille, Arsenal over two spells and Milan is in full flow as the Frenchman presents his designs for life. Flamini, who eats once a day, sips hot water in a Soho vegan cafe as he espouses the benefits of an environmentally friendly lifestyle. “Climate and health are related,” he says. Turning 40 next month, he last played top-level football for Getafe in 2019 but still talks and looks like an athlete. He is also a partner in GFBiochemicals, a leader in sustainable alternatives to oil-based products, with levulinic acid, a potential precursor to biofuels replacing fossil fuels ingredients in everyday products. Swapping renewables for fossil fuels is big business and Flamini was on the ground floor, starting up the business in 2008 soon after joining Milan. The company now works with multinationals seeking to decarbonise. A long road lies ahead towards worldwide safe levels of carbon. “Climate change is being ignored,” he says. “If we talk about countries like India and China, people can’t exercise outdoors any more. Do we want to get there? “Plastic? It is everywhere in the sea. Even if I don’t care about the environment, babies are being born with microplastic in their organs. We cannot ignore it.” He believes football can play its part in averting the environmental catastrophes that threaten the planet. Football? The sport of private jets, fast cars, air-miles-busting transcontinental tournaments and petrodollar-funded club ownership? The sport where Gianni Infantino, the Fifa president, has partnered with Saudi Arabia and where Aramco, the world’s largest oil company, is set to sponsor the governing body for $100m a year? Yes, football. Flamini is a frontman for Green Football Weekend, an initiative held this weekend – Sky Sports swapping their yellow for green, the BBC and TNT involved, too – that addresses the grassroots, involving schools in delivering the message that eating vegetarian food is helpful to the environment. Fans can download a cookbook featuring a Raheem Sterling cauliflower, potato and spinach curry recipe the Observer is told is particularly tasty. That eating vegetarian more often – though not necessarily exclusively – can counter the high level of carbon byproduct from mass-produced meat is a leading message. Small changes eventually equating to giant steps is the strategy. “We need to empower people,” says Flamini. “Climate change is a big and scary topic. If you are told you must save the world, you feel useless as an individual. You must break it down, tell them how they get impacted by pollution and plastics, with everyday things like shampoo and shower gel coming from fossil fuels. If you multiply people making a change by billions then you can make a big impact.” One of the campaign’s aims is to depolarise the issues of climate change that, to take the UK as an example, have become bogged down in battlegrounds such as London’s ultra-low emission zone, low-traffic neighbourhoods and Labour’s on-off pledge of £28bn on green investment. Throwing the issue back to football takes the edge off the spikiness and the UK game has not been immune to climate change, considering flooding has severely affected schedules in the lower divisions this winter. “Our game is being affected but we are not blaming anyone here,” says Flamini. “We are bringing the table out and trying to make sense. Football – and sport – is one of the last things we have that can unite people, can address everyone, from rich to poor, people from every part of the world. Football needs to stand up for climate change. What can they do? Start finding solutions. Offsetting carbon is one of those solutions. But it’s the minimum.” With men’s World Cups in North America in 2026, across three continents in 2030 and in Saudi Arabia in 2034, Flamini, on the environmental committee for the Paris 2024 Olympics, has more than a few ideas for the organisers. “Sourcing food locally, vegetarian options for the athletes and the fans, avoiding plastics, using products made more sustainably than from fossil fuels, trying to reduce transport. It’s about integrating all those solutions into planning. It’s a journey.” His own path includes giving up pescetarianism when the Arsenal doctor Gary O’Driscoll showed him high levels of mercury in his monthly blood tests; a Marseille childhood and a passion for diving had already told him the Mediterranean was full of pollutants. He freely admits he drove a sports car in the fleet of Ferraris that pulled into the Milanello training ground. “Take a young kid who has grown up in a difficult area, and didn’t always have food on the table, and imagine that the poor kid becomes a very rich athlete. That kid had a dream to play in front of hundreds of thousands of people and that became reality. He also had a picture of a sports car on his wall, it is very difficult to tell this kid he can’t achieve that dream, too. “The footballer will probably have a sports car but he can do other things, like become a vegan, or offset his carbon, or create awareness through his platform. Maybe later he’ll get an electric car.” For Flamini, the Eurostar now takes the strain of a hectic business life shared between London and Paris for a previous private jet frequent flier. A commitment to the environment can make everyone hypocrites. “What if you have family in New York?” he says. “You cannot tell people to take the boat but when people have the choice, we want them to take the green option.” If his approach to changing opinions in football and the wider business world is largely conciliatory and commercially minded he retains an admiration for the direct-action activism of Greta Thunberg and her ilk. “It’s inspiring,” he says. “At 12 or 13 I was kicking a football around. It’s a message of hope and if you push the message to corporations – to football – those kids are the consumers of tomorrow. Guys, it’s time to change.”