Lilly Platt is too young to vote in the upcoming European Parliament election. The 11-year-old won't be eligible to do so until 2026, when she turns 18.
Yet her grandfather, 79-year-old Jim Platt, has found a way for her voice to be heard.
When he goes to the polls, Mr Platt will vote for the candidates Lilly has chosen.
The pair, who are originally from the UK but live in the Netherlands, are urging voters in all 28 EU states to do the same when they cast their ballots from 23-26 May.
It is Lilly and other young people, Mr Platt told the BBC, who will suffer the worst effects of climate change.
"The campaign against inaction on climate change is almost entirely in the hands of the younger generation," Mr Platt said.
"If the young can't have their voices heard by standing on the street and waving placards, there are other ways that it can be done - by this proxy vote process."
What started off as a symbolic gesture to "make politicians listen" has rapidly transformed into a global movement on social media.
✏#ICanVote at the #EUelections2019 ✏— Lillys Plastic Pickup (@lillyspickup) May 10, 2019
Thanks to the #ClimateStrike #FridaysForFuture my grandpa will vote for me ❤
We want #ClimateAction Talk to your (grand) parents & ask for their vote too. Let's make politicians listen. #ClimateCoup @Europarl_EN #👨🦳✏👧🏻🌍🙏 @GretaThunberg pic.twitter.com/iHbqzaXs5n
A hashtag that stemmed from their campaign, #givethekidsyourvote, is gaining traction on Twitter, inspiring parents and grandparents across the world to follow their example.
Swedish schoolgirl Greta Thunberg, the 16-year-old face of the youth climate movement, has backed the idea. When calling for climate action, UN Secretary-General António Guterres and Pope Francis have also evoked their responsibility to younger family members.
Mr Platt is hoping EU citizens take heed of their appeals and "look into the future" when choosing their MEPs.
As a retired geologist in the mining sector, he has seen the environmental impacts of the extractive industries first hand.
Because older voters like him do not have "a stake in the future", he believes they should defer to young people.
The top 5 most important issues for the #EUelections2019 :— Greta Thunberg (@GretaThunberg) May 11, 2019
1. Climate and ecological breakdown
2. Climate and ecological breakdown
3. Climate and ecological breakdown
4. Climate and ecological breakdown
5. Climate and ecological breakdown
6. Climate and ecological breakdown
As Secretary-General, I have many battles.— António Guterres (@antonioguterres) May 16, 2019
As a grandfather, the battle against climate change is the battle of my life.
It’s a battle we’re not winning.
We need stronger political will and urgent #ClimateAction to save our planet and our future. pic.twitter.com/gURUd2QwDc
By going on a school strike every Friday, his granddaughter has been fighting for her future. Inspired by Greta's Fridays for Future movement, Lilly has been taking action for months and has her own litter-picking campaign, Lilly's Plastic Pick Up.
Her "proxy vote" at the EU election, she said, is another opportunity to show politicians that human-induced climate change "is real".
Lilly told the BBC: "I think that all children should have a say in the European election."
Andreas Magnusson, a 15-year-old climate activist from Sweden, agrees. His father similarly said he should "decide who he will vote for".
The MEPs elected to the EU parliament will take office for "the most important five years in human history", Andreas told the BBC.
By 2030, a UN report warned last year, global carbon emissions must be cut by 50% to avert dangerous and potentially irreversible climate change.
"The climate crisis won't wait for us anymore," Andreas said. "That's why children must have a say in this EU election."
FridaysForFuture has completely taken over my life. The only thing I can think about right now is climate change, climate change and climate change.— Andreas Magnusson (@AMagnussonn_) March 18, 2019
It's time for the politicians to act!
I will not wait until you act. I will make you act!!#FridayForFuture #climatestrike pic.twitter.com/5A3JR2MQJo
By the end of the next decade, many of today's children still won't be eligible to vote. Only one of Michael Flammer's three children, for example, will be over 18.
Mr Flammer told the BBC that none of his children - aged one, three and nine - are old enough to be cognisant of climate change or its consequences. Instead, Mr Flammer, from Cologne, Germany, will cast his vote with them in mind.
"Finding out about the consequences that my kids will experience is more than terrifying," Mr Flammer, a procurement director for a publisher, said.
"They cannot tell me how to vote, so I vote what's best for them in terms of fighting climate change."
Mr Flammer and Mr Platt appear to be exceptions to studies which suggest older people care less about climate change than the young. Their concern for the fate of young people is not confined to Europe either.
The movement to give children the vote has resonated with parents and grandparents in Australia, too. Campaign group Australian Parents for Climate Action is urging people to #givethekidsyourvote ahead of the country's federal elections on 18 May.
"I think this is one of the most powerful things we as adults can do," co-founder of the campaign, Heidi Edmonds, told the BBC.
"We can listen to the kids on how they want to vote. Or, if our kids are too young, we can vote as best as we can for them."
This election Australian Parents for Climate Action are calling on adults to #givethekidsyourvote, listen to the kids on climate, and make this the #climateelection #AusVotesMay18— Australian Parents for Climate Action (@ap4ca) May 15, 2019
Here we share some of our stories.https://t.co/rfZVwJgTnZ
Back in the Netherlands, Mr Platt said his granddaughter has already decided how his vote will be cast.
But, he says, whatever the outcome of the election, Mr Platt says it is "part of our legacy".
"You can vote for yourself, of course, but it's really the future of the young that's at stake," he said. "We want to leave a better world for them."