If you announcement footballers wearing greenish armbands during Premier League, EFL and Women's Super League games connected Saturday and Sunday, it's each portion of the Green Football Weekend - with immoderate clubs, players and fans progressive successful tackling clime alteration by reducing their biology impacts.
BBC Sport looks astatine what's going on.
Which players are involved?
Brentford defender Ben Mee has been a starring dependable successful the Premier League connected these issues for immoderate time, telling BBC Sport: "I became funny successful reducing my c footprint chiefly from having children, and reasoning astir what the aboriginal could look similar for them."
Heart of Midlothian and New Zealand guardant Katie Rood has been encouraging her team-mates to halt utilizing integrative h2o bottles and see vegan options, and said: "We've got 1 world, 1 planet, and I deliberation often we are detached from the impacts and imaginable harm to the satellite erstwhile we marque decisions successful our day-to-day lives.
In a quirk of the fixture list, possibly the 2 astir progressive players conscionable connected Saturday erstwhile Funso Ojo's Port Vale play Wycombe Wanderers, with their midfielder David Wheeler announced this week arsenic the PFA's sustainability ambassador.
Ojo has clocked up much than 260 activities that Green Football Weekend organisers accidental could magnitude to much than 500kg CO2e saved - astir the aforesaid arsenic a instrumentality formation from London to Cairo.
"I've not ever been specified a greenish activist," helium said. "I utilized to thrust a Porsche, but I changed. I told the nine I privation to get into an electrical scheme, astir a plant-based diet, the integrative bottes we were using.
"Since I switched to my greenish journey, I person been passionate astir it. I americium successful a presumption wherever possibly determination are hundreds of radical looking astatine us, possibly it's 5 people, but it's tiny changes."
What person fans been doing?
Some fans person besides been driving alteration astatine their clubs.
Burnley instrumentality Cat Jebson acceptable up a radical called the Sustainable Clarets.
"It fundamentally started with a mates of emails astir vegan options and what we could bash and I was truly pleasantly amazed by however accelerated and however thorough the nine were successful their response," said Jebson.
Burnley person welcomed the engagement of the group, seeing it arsenic a "critical friend", and Jebson says: "What we tin bash is enactment it adjacent much successful the Burnley context. Why it's truly important for the town.
"Disproportionately, clime alteration affects poorer radical more. So it is simply a occupation that we request to code close astatine the precise apical of the Football Association, adjacent the government."
Elsewhere, it was a instrumentality who led Southampton's archetypal squad to get escaped of integrative bottles from the dugout connected matchday, portion Everton person created a fans' forum and Everton for Change group, which is led by protagonist Chris Halsall.
Environment manager Halsall present gets to harvester his nonrecreational skills with his passionateness for his club, saying: "The caller stadium volition supply the nine with a monolithic step-up successful biology performance. I've been capable to enactment up to day with each the biology considerations wrong the plan and physique process. Ultimately our situation to the nine is to go net-zero."
How astir the clubs?
Travel is an important area, with overmuch of the spotlight connected the information the bulk of apical teams inactive regularly instrumentality home flights, implicit precise abbreviated distances.
This weekend, Liverpool volition beryllium travelling to their lucifer astatine Wolverhampton Wanderers successful a manager that volition beryllium powered by "sustainable fuels", with an emanation redeeming of 90% connected a mean diesel coach. Tottenham Hotspur's squad coaches volition beryllium powered by bio-fuel, which is the lawsuit for each of their location games.
Fan question is the largest portion of sport's footprint, and Norwich City are encouraging supporters to usage E-bikes to get to the crushed for their lucifer against Burnley, portion Carlisle United are organising a locomotion to the crushed for the crippled against Harrogate Town.
What are the challenges?
While clubs, players and fans bash their bit, determination are ongoing questions for those astatine the apical of the crippled some domestically and internationally astir whether shot is making capable advancement successful its efforts to decently code its emissions and narration with the environment.
The crippled is growing. Uefa is expanding European competitions, Fifa is doing likewise for some the men's and women's World Cups, and Premier League clubs inactive alert immense distances connected pre-season tours, and galore instrumentality planes to home games.
Freddie Daley is simply a researcher astatine the University of Sussex, and specialises successful shot and the environment.
"Flying volition proceed to beryllium a crux for football's sustainability push," said Daley.
"The inclination towards playing much games successful a season, and holding bigger planetary tournaments, requires immense amounts of aerial question for some players and fans.
"This isn't conscionable the remit of clubs. Leagues tin play a starring relation successful adjusting the fixture docket truthful clubs tin marque usage of lower-carbon modes of transport and bash not person to trust connected short-haul flights.
"There's besides the optics. The science of sustainable behaviour alteration emphasises the value of enactment and integrity successful getting radical to follow lower-carbon lifestyles.
"If fans spot teams jumping connected planes alternatively of a two-hour bid journey, it tin harm the connection that we each request to instrumentality enactment to code the clime crisis.
"Worse still, if a shot nine is making nationalist statements astir the request to code clime alteration and asking its fans to displacement their behaviours, but past uses short-haul flights, it verges connected hypocrisy."
Campaigners are besides utilizing Green Football Weekend to question the sport's narration with wealth from fossil substance companies, whether that beryllium via nine ownership, the staging of events oregon sponsorship.
Frank Huisingh, from Fossil Free Football, wants to spot restrictions connected advertising and sponsorship.
"Young shot players, similar their fans who travel their each move, unrecorded successful the epoch of a rapidly escalating clime crisis," helium said. "It is unfair to inquire young players to beryllium a moving billboard for large clime polluters threatening their future."
It is expected the galore tiny actions by fans, clubs and players crossed Green Football Weekend volition harvester to marque a important chopped successful emissions, and the anticipation from organisers is determination volition beryllium a bequest which sees that continue.
Green Football Weekend's Sarah Jacobs said: "This isn't a one-off. It's astir driving ongoing speech and enactment connected climate, galvanised by an yearly infinitesimal that brings unneurotic the full footballing assemblage - a infinitesimal we privation to spot turn successful ambition and scale."
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