Thousands of young people marched through cities in Asia Friday, kicking off a global day of student protests that aims to spark world leaders into action on climate change.
Classrooms in capitals from Lagos to London are expected to be empty, as the ambitious organisers of the global student strike aim to stage 1,000 demos in more than 100 countries.
Malta is also expected to be taking part.
Students flooded into the streets in Wellington, Sydney, Bangkok and Hong Kong carrying placards that read "There is no planet B", "You're destroying our future" and "If you don't act like adults, we will."
Abigail O'Regan, 20, who was marching in Wellington, told AFP: "This is young people taking the reins and realising that they do have people power, that's really awesome."
In Sydney, 18-year-old Edward Gay called for "100-percent renewable energy", arguing "that is the only way we are going to be saving lives in this country and all over the world."
Fellow protester Charles Rickwood, 18, warned that if nothing is done, Australia's famous Great Barrier Reef could be destroyed.
"Especially if current trends in the environment continue, we'll see the one, two degrees increase in our ocean then it will simply become unsustainable and we could lose the entire Great Barrier Reef," he told AFP.
Parents of students in Christchurch in New Zealand were warned not to collect them from the city centre during the lockdown after two crowded mosques were targeted in a mass shooting.
'Green political activists'
The worldwide protests were inspired by Swedish teen activist Greta Thunberg, who camped out in front of parliament in Stockholm last year to demand action from world leaders on global warming.
"We are only seeing the beginning," tweeted Thunberg, who has been nominated for the Nobel Peace Prize for her activism.
"I think that change is on the horizon and the people will stand up for their future."
However, they attracted mixed reactions from politicians.
In Australia, Education Minister Dan Tehan questioned whether the protests truly represented a grassroots movement.
"Students leaving school during school hours to protest is not something that we should encourage," he told public radio.
"Especially when they are being encouraged to do so by green political activists."
His comments came as a report showed Australia's annual carbon emissions had reached record levels, raising questions about whether it will meet targets agreed under the 2015 Paris climate agreement.
But the budding activists received encouragement from New Zealand Prime Minister Jacinda Ardern, who said it was important for the young generation to send a message.
"We hear you and we're getting on with setting a path for carbon neutrality," the 38-year-old leader said in a statement.
"Please keep bringing as many people as you can with you because we simply won't achieve our goals alone."
Wellington university student Josie Mason, 20, said she was "excited by the fact that youth are being heard and are making a stand right now."
"They call our generation the 'slacktivists' because it's really easy to say you're going to an event on a Facebook page or like something but not really do anything," she said.
Despite 30 years of warnings about dire impacts, carbon dioxide emissions hit record levels in 2017 and again last year.
Loading the atmosphere with greenhouse gases at current rates, scientists agree, will eventually lead to an uninhabitable planet.
"On climate change, we have to acknowledge that we have failed," Thunberg told the global elite in Davos in January.
The Paris treaty calls for capping global warming at "well below" two degrees Celsius.
The planet is currently on track to heat up by double that figure.
The UN's climate science panel warned in October that only a wholesale transformation of the global economy and consumer habits could forestall a catastrophe.
In Hong Kong, activists dressed up as polar bears and sharks to highlight the damage done to the environment by climate change.
"The main thing we want people to realise is that we are not only asking the Hong Kong government to do more, it is also people themselves who need to do more," said Zara Campion, 17, co-organiser of the strike.