Forced off the streets by the pandemic and alarmed by delays to crucial UN climate talks, young activists have had to get creative online to keep up the pressure on world leaders to tackle global warming.
Before the new coronavirus struck, demonstrations across the world attracted millions of young people, galvanised by Greta Thunberg's school strikes and personal experiences of the accelerating impacts of climate change.
But the pandemic put a stop to street protests and saw the United Nations delay crunch Conference of the Parties climate talks until 2021.
It was "devastating", said 17-year-old Malaika Collette from Ontario, Canada.
In response, youth organisations set up their own "Mock COP", a two-week virtual meeting with dozens of delegates from 140 countries, to show what they would do if they were in charge.
Scientists and campaigners say progress at the annual UN meetings -- which began in 1995 before many of this generation of activists were born -- has already been unacceptably slow.
"World leaders must do better," said Collette, who took part in the youth talks.
"It's hard to understand why the entire world isn't fighting like their life depends on it."
Raging wildfires, sea-level rise, more destructive tropical storms and intense heatwaves all bear the fingerprint of global warming -- which has seen temperatures rise one degree Celsius since the mid-19th century.
For many young activists, the threat of climate change is already very close to home.
When deadly Typhoon Vamco came smashing through the Philippines last month, Mitzi Jonelle Tan could not contact her mother at their home in Marikina City.
"I was so afraid because I didn't know if she was still alive, if she was stranded on the roof, if I still had a home to return to," the 24-year-old, one of the Mock COP speakers, told AFP.
'Clock is ticking'
The 2015 Paris climate treaty, signed by virtually all the world's nations, calls for capping global warming at "well below" 2C.
Since then the world has seen its five hottest years on record.
In 2018 the UN's climate science panel (IPCC) said only a wholesale transformation of the global economy and consumer habits could forestall catastrophe.
Around the same time, a then 15-year-old Thunberg began attracting attention for her weekly solo protests outside the Swedish parliament, with photographs shared on Instagram and Twitter.
The movement resonated because many young people have grown up with "very clear markers of climate change," said Dana Fisher, Professor of Sociology at the University of Maryland and contributing author on activism and engagement for the next IPCC assessment report.
Fisher said she was sceptical that global online events like the youth talks would be more effective than local action, but said she understood why campaigners felt the sense of urgency.
"The clock is ticking and they do not see the kind of political change scientists say is necessary to get us out of a climate emergency," she said.
Even world leaders are showing their frustration.
"My hope is based in the youth," said UN chief Antonio Guterres in a September interview with AFP and the Covering Climate Now media initiative.
"Because let's be frank, my generation largely failed to address the challenges that the world faces."
'Lack of ambition'
The UN meetings are dominated by "greed, bigotry and lack of ambition", said Catalina Reyes-Vargas, 24.
But the Mock COP spokesperson from Bogota, Colombia, said it was useful to know how they work.
"We get involved in strikes, in protests and we use a lot of hashtags and so on, but most of us don't understand how the decisions are being made," she said.
The Mock COP wrapped up on December 1 with a declaration echoing the style of the UN gatherings.
But theirs was not diluted by diplomacy.
"Governments around the world are failing to meet their legal and moral obligations to tackle the climate and ecological crisis, despite the increasing urgency and projected scale of the crisis," it said.
Recommendations included criminalising deliberate environmental destruction, banning fossil fuel developments and a "Green Recovery" from the pandemic.
Future on the line
Australian activist Luca Saunders, 15, wants young people to have a seat at the table at next year's UN climate meeting in Glasgow "because obviously it's our future that is on the line".
As a younger child growing up in the Blue Mountains area near Sydney, she thought of fire days as exciting, unexpected school holidays.
Recently though the bushfires have become altogether more threatening.
"Last year, there were large fires circling and closing in on our house... The whole town was only just saved by firefighters," said Saunders, adding that the experience has driven her activism.
But she said the pandemic has caused a loss of momentum.
"There definitely isn't the same energy within the movement as there was when we were organising mass demonstrations," she said.
Campaigning has been affected across the world.
In the US, Fisher surveyed 171 organisers of Earth Day -- held on April 22 -- and found more than half said Covid-19 had affected their political work "a lot".
But the social media movement continues.
Thunberg's Fridays for Future has called for a day of largely-online action on December 11, ahead of a summit to mark five years since the Paris accord.
Tan's activities in the Philippines are normally face-to-face, including going to classrooms to give talks about climate change.
But she said the online Mock COP conference had been useful, helping in "solidifying our global youth movement".
"At this point, we need to do all of it at the same time," she said.