Some 5,000 protests have taken place around the world, culminating in a New York City march led by Greta Thunberg. From Australia to Thailand to Germany, young people challenged politicians to act. Read the latest here.
All updates in the UTC/GMT time zone
03:00 Hundreds of people, many of them schoolchildren, rallied in downtown Los Angeles. Mayor Eric Garcetti praised children for taking to the streets to voice their concerns about climate change. "Do we want to look back at this day and tell our students they should stay in school? Hell no! Take to the streets and claim your future!"
Protests were also held in the San Francisco Bay Area.
02:00 Hundreds of Amazon workers in Seattle walked off the job demanding the internet retailer implement more climate friendly policies. Amazon ships more than 10 billion items a year. On Thursday, the company pledged to cut fossil fuel use and announced it had ordered 100,000 electric vans to deliver packages beginning in 2021.
00:20 Teen climate activist Greta Thunberg told large crowds in New York that they formed part of "a wave of change."
"If you belong to that small group of people who feel threatened by us then we have some very bad news for you, because this is only the beginning," the 16-year-old said in Manhattan's Battery Park. "Change is coming whether they like it or not."
23:35 Thousands took to the streets in Brazil, many taking aim at President Jair Bolsonaro, who they say is allowing fires to destroy the Amazon rainforest, worsening the environmental crisis. Protesters called for Environment Minister Ricardo Salles to be ousted.
In response to the protests, Salles acknowledged the existence of man-made climate change and said demonstrators were right to be concerned about the future.
"I have children and I am concerned about their future too," he said in an interview.
19:49 The protests even spread as far as Antarctica, from where ecologist Kim Bernard tweeted her support for the striking students:
18:38 High schoolers in Miami Beach, Florida, say they are marching to draw attention to rising sea levels driven by increasing temperatures — a real concern for residents of the coastal island city.
"I'm scared that I am going to lose my house," said 16-year-old protester Aleksandar Demetriades.
18:07 Protesters in Mexico, Brazil, Argentina, Peru, Colombia, El Salvador and Chile are joining the climate strike.
Students at the University of El Salvador declared a "climate emergency" and demanded justice as they marched through the Central American country's capital, San Salvador.
El Salvador is part of the area referred to as the Central America Dry Corridor, one of the world's most vulnerable areas to climate change. Experts warn that water scarcity, severe drought and food security could become major problems there in the next few years.
16:32 Climate rallies are kicking off in Washington D.C. and New York, where tens of thousands of protesters led by Greta Thunberg are marching from Foley Square in Lower Manhattan to Battery Park. Authorities in New York say some 1.1 million students have been given parental permission to skip school for the event.
The city's mayor, Bill de Blasio, expressed his support on Twitter, saying "the time to act is NOW, before it's too late."
Similar marches are planned in cities across the US.
16:16 British opposition leader Jeremy Corbyn has criticized Donald Trump in an address to protesters near parliament in London. The US president has questioned the science of climate change and in 2017 decided to withdraw his country from the Paris Agreement.
"Let's have no more of this hand-holding for Donald Trump," Corbyn said. "Let's quite simply say that we want every country on board on this (Paris Agreement), every country fully signed up and going a lot further than that."
Around 100,000 people were taking part in the London demonstration.
15:24 Large crowds of young people have taken to the streets in major centers across Europe, including Brussels, Paris, Helsinki and Stockholm — the city where Greta Thunberg began her school strike a year ago.
"This is about my future, not only my future, but the future of my entire generation and all the generations to come after ours," said Tristan Vancleef, 16, in the Belgian capital. Some of the protesters held signs reading "I won't go to school until you make it cool" and "The warm earth destroys our cold beer."
15:03 Thousands of students are gathering outside the British Parliament in London to pressure lawmakers to ramp up climate action.
One of them, 16-year-old Jessica Ahmed, said that "if politicians were taking the appropriate action we need and had been taking this action a long time ago ... then I would not have to be skipping school. I would be doing the maths exam I have studied for."
Rallies are also taking place in dozens of other UK cities, including Birmingham, Glasgow, Belfast, Oxford, Cardiff, Cambridge, York, Nottingham, Leeds and Liverpool.
14:47 Swedish climate activist Greta Thunberg says she's "very hopeful" after witnessing the huge turnout around the world. Speaking via a livestream in New York, she said it was "a historic day."
"We will put so much pressure on (politicians) that they just can't fail," she said. "We, people of all ages, have shown what we stand for, now it's up to them to show that they have listened to us. Now they have to prove it."
14:33 Here's one for the German speakers among you — a school sick note courtesy of satirist and German politician Martin Sonneborn explaining, with tongue firmly in cheek, that a student's Friday absence has nothing whatsoever to do with the climate marches or concerns about the fate of the planet.
13:51 As hundreds of thousands demand climate action, the German government has agreed on a €54 billion ($60 billion) package of measures aimed to slash greenhouse gas emissions by 55% by 2030 compared to 1990 levels. The deal follows weeks of negotiations, and includes a price on carbon and a ban on installing oil-fired heating in buildings from 2025.
In announcing the plan, Chancellor Angela Merkel said young people were "rightly demanding that we do something to help them have a good chance of survival."
The German leader added that she was particularly impressed by climate activist Greta Thunberg and her plea to "unite behind the science."
"We're not being ideological, rather, we're doing something for which there is such massive evidence that we have to act against it," Merkel said.
13:32 Protest organizers in Germany estimated a turnout of more than 1.4 million people nationwide, with more than 200,000 in Berlin, although authorities counted about half that number. Police say at least 70,000 are taking part in peaceful protests in the northern port city of Hamburg, while about the same number have taken to the streets in the western city of Cologne. Crowds of more than 20,000 also gathered in Munich, Hannover, Münster and Freiburg.
13:12 Hundreds of Ugandan schoolchildren have joined a march on the outskirts of the Kampala, urging adults to act to curb global warming. According to the United Nations, the African continent will be severely affected by rising temperatures that will likely lead to periods of prolonged droughts and flooding.
"How many people have to die for you to act?" 12-year-old activist Cissy Mukasa asked on her banner. "This time government must act."
12:49 A small protest is underway under tight security in the Afghan capital, Kabul. About 100 young people marched through the center of the city escorted by soldiers and an armoured personnel carrier.
One of the event's organizers, Fardeen Barakzai, said: "we want to do our part. We as the youth of our country know the problem of climate change. We know war can kill a group of people ... the problem in Afghanistan is our leaders are fighting for power but the real power is in nature."
11:42 In Berlin, Sea Watch Captain Carola Rackete tells the crowd: "we adults are responsible for the fact that the earth is dying ... we should not be under the illusion that our individual actions can do anything to turn the situation around." She called on everyone to join an Extinction Rebellion protest scheduled for October 7, promising that "this will not end here."
One Berlin protester, 71-year-old Doris, told DW: "The topic of climate changes bothers me, because nothing is happening. I think, in my generation, most people know what is going to happen...but they say no, climate change doesn't directly threaten me."
13-year-old Ella said, "I hope the politicians understand how serious this is."
11:01 Tens of thousands of South Africans took to the streets of Johannesburg, calling for a ban on new coal power stations and new fossil fuel mining licenses and a commitment to using only renewable energy by 2030. Outside the Gauteng provincial legislature, protestors delivered a memorandum declaring that "climate change is the greatest threat we are faced with."
10:16 People began gathering in London near the Thames as part of the UK's more than 200 pro-climate events scheduled for Friday. Labour party leader Jeremy Corbyn is due to address strikers outside parliament later in the day.
"This is going to be the biggest climate mobilization that the UK, and the world, has ever seen," Youth Strike 4 Climate tweeted late morning.
10:04 As Berlin protesters began to gather at the Brandenburg gate, other smaller cities held climate strikes as well, including Essen and Bremen. Several thousand people in the Black Forest city of Freiburg marched through the town center, which is closed to vehicle traffic for environmental reasons.
"This is an impressive and strong signal from our citizens," said Freiburg Mayor Martin Horn.
Football team SC Freiburg also took part:
09:28 Achim Steiner, head of the United Nations Development Program, said Germany must take a more active role in fighting climate breakdown. Chancellor Angela Merkel was once known as the "climate chancellor" but in recent years, she appears to have set those priorities aside.
"Hopefully she will present at the climate summit a German level of ambition that reflects the country's capacity, but also its responsibility," he said in New York.
"Right now, Germany has been struggling to meet the short-term targets that it's set itself in its own climate strategy. And clearly that is something that neither the government nor industry nor the public in Germany wants to continue," Steiner added.
09:10 Other European nations, including the Czech Republic and Poland, joined Germany to take part in the pro-climate action. Thousands of young people gathered in Warsaw, Bratislava and Prague. In Poland, organizers described the turnout as "massive."
In Finland demonstrators in costume stopped outside the parliament building in Helsinki. One man dressed as Santa Claus held a sign declaring "my house is on fire."
08:10 Kenya began its strike with a march in the capital, Nairobi. Protesters in Kenya were specifically demanding an end to government plans to build new coal power plants.
07:58 India, the Philippines and Hong Kong joined other Asian nations as protests gathered steam throughout Friday. In India, people gathered in Mumbai and outside the Ministry of Housing and Urban Affairs in New Delhi, chanting "I want to breathe clean!" In Hong Kong, some demonstrators took a break from pro-democracy protests against Beijing to support the climate strike.
07:43 Protests were already underway early on Friday in Germany, where demonstrators blocked early morning traffic in Frankfurt in the city's central Baseler Platz square.
In Berlin, hundreds of protesters got on their bicycles and drove around the center of the city as Chancellor Angela Merkel's cabinet ministers met to discuss possible plans to address the climate crisis.
07:04 Organizers estimated that a total of 300,000 people took part in Australian marches, which included the cities Brisbane, Sydney, Melbourne, and the capital, Canberra.
06:30 Indonesia, Japan, Thailand, Bangladesh, and the Solomon Islands were also amongst the first nations to hold protests that day. In Bangkok, thousands gathered outside the Ministry of Natural Resources and the Environment to protest, while on the Indonesian island of Borneo, locals protested the devastating effects of deforestation and forest fires.
"Thailand must set a target for 100% renewable energy share and decarbonize by 2040, by divesting from fossil fuels and phasing out coal by 2025 to limit carbon emissions and further climate change impacts," read an open letter from protesters to the environment minister.
Some 200 Thai demonstrators rushed the ministry building and dropped to the ground to symbolize the deaths that are and will be brought about by climate change.
03:00 Thousands of people across Australia kicked off global climate protests on Friday, marking the start of what is expected to be a major day of action.
Protesters were demanding world leaders gathering for a UN Climate Action Summit act to stop an environmental catastrophe, and more locally, for government and business to commit to a target of net-zero carbon emissions by 2030.
Climate change has become a particularly divisive issue in coal-rich Australia, where the conservative government has consistently failed to act in any meaningful way to combat climate change.
Australian Finance Minister Mathias Cormann warned students against partaking in the action, saying: "When school is sitting, students should go to school."
Danielle Porepilliasana, a high school student in Sydney's inner west, said climate change was the biggest threat to her generation.
"World leaders from everywhere are telling us that students need to be at school doing work," said Porepilliasana. "I'd like to see them at their parliaments doing their jobs for once."
nm,es/sms (AFP, AP, Reuters, dpa)