A sea of thousands - 60,000, according to local authorities, and 250,000 according to organizers - turned out on Friday in New York for a massive "Global Climate Strike" march demanding urgent measures be taken to reverse climate change.
Most of the marchers seemed to be young people and among them was 16-year-old Swedish environmental activist Greta Thunberg, the leader of the world youth climate movement, who opted to remain largely out of the limelight and leave leadership of the march to leaders from the Americas such as Alexandria Villaseñor and Xiye Bastida.
"Around the world today about four million people have been striking," Thunberg said in addressing the crowd. "This is the biggest climate strike ever in history and we all should be so proud of ourselves because we have done this together."
Organizers said that more than a quarter million people were on hand, although New York Mayor Bill de Blasio, who also turned out for the protest, estimated participation at about 60,000.
In any case, the marchers on several occasions swelled - albeit peacefully - past the many police officers deployed to keep order at the protest, especially during the early stages.
"No to Planet B," "No to fossil fuels" and "I know part of the solution: No to pollution" were some of the hundreds of slogans on signs carried by participants demanding immediate action by world leaders who next Monday will attend the United Nations Climate Summit in New York.
The protest had nice, sunny weather, and got under way from Foley Square, moving to Battery Park, where Thunberg spoke to the crowd.
Mexican activist Xiye Bastida, 17, who led the march, told EFE that she had participated "because climate change is affecting us and it's affecting our future."
"If we don't do something right now, we don't know what's going to happen," said the student who on Monday will participate along with Thunberg in the UN Climate Action Summit.
Meanwhile, at UN headquarters, hundreds of officials gathered on Friday to support the protests, an event at which the driving force behind the Summit, Mexico's Luis Alfonso de Alba, spoke, saying that "there's no plan B" for dealing with global warming.
Bastida said she wanted to tell the world leaders who will be on hand on Monday at the UN session to "take a second to reflect on what's happening," adding that she and other activists will present several petitions to the assembled presidents and heads of state.
"Stop using petroleum products, provide work for oil industry workers, a fair transition, and we want them to keep in mind that they have to protect our future, because we're 20 percent of the present but we're 100 percent of the future," she said.
More than 50 non-governmental organizations that defend the environment took part in the event that kicked off at noon and concluded in mid-afternoon, and similar marches and protests were held all across the US.
According to the NGO 350, in agreement with what Thunberg had said, more than four million people around the world turned out to show their support for this movement.
Among the participants in New York was Brazilian activist Sonia Guajajara, who said she was "representing the indigenous peoples of the world."
The former Brazilian vice presidential candidate, the first indigenous woman to run for that post, told EFE that "We're joining the other voices of the world to denounce the genocide in Brazil and also to speak about the role of the indigenous peoples and their lands in maintaining climate balance."
A large number of students, who needed the OK from their parents to attend the "Climate Strike," participated for the first time in a demonstration, including 15-year-old Daniel Abicher, who attended alone.
He told EFE that he wanted to get involved in climate activism and added that his parents were, on the one hand, concerned because he was at the protests, but also "thrilled" that he is fighting for "a better world."
The New York march proceeded peacefully, with participants clearly hoping that their voices will reach the offices of world leaders and businessmen.
Among the participants were people costumed as globes, wearing gas masks to denounce pollution, carrying cut-out ocean waves in solidarity with the seas and outfitted as pink flamingos to call attention to the danger to many of the world's species.
Meanwhile, in Ecuador environmentalist groups on Friday demanded that the government declare a "climate emergency" in the country, the aim of which would be to free up resources to undertake efforts to repair the ecosystems affected by extractive activities such as oil drilling and mining.
Daniel Villamar, the spokesman for the "Friday for Future Ecuador" collective, which called a day of protest on downtown Quito's Independence Square near the Government Palace, told EFE that the pressure tactic was staged in conjunction with the worldwide day of protest against climate change which seeks to force governments to take responsibility for the planet's environmental health.
Elsewhere in the Americas, young people from Argentina, Mexico, Chile, Peru and more united on this day of protest to echo the demonstrations taking place in thousands of cities across the United States
About 1,000 people - mainly children and university students - also marched in Mexico City to demand that the national government there declare a climate emergency shouting slogans such as "Not one more degree, not one more species murdered" and "We want a future, not hydrocarbons."
"We're asking them to declare a national climate change threat. In the short term, we want them to stop fracking, and the (planned) Dos Bocas refinery, bye, we don't want it," Nicole Brockman, the spokesperson for Fridays for Future Mexico told EFE.
Other protests were staged in the Mexican cities of Monterrey, Guadalajara and Puebla, as well as in Australia, India, South Korea and Indonesia.
Among the demands set forth by the roughly 40 civil organizations that joined the protests are reducing greenhouse gas emissions by 50 percent by 2030 and eliminating such emissions by 2050, focusing on human rights in climate actions, for government decisions to be based on science and for the Paris Climate Agreement commitments to be fulfilled.
However, the Mexico City march did become uncomfortable for some activists because an anarchist group positioned itself at the head of the organizers. After a brief altercation, however, the anarchists left and the march continued peacefully.
Students, teachers, ecological activists and even authorities in at least 20 Brazilian cities joined the worldwide mobilizations to demand that governments take concrete and effective action against climate change.
The marchers - mainly students - moved down the central avenues in Sao Paulo, Rio de Janeiro, Belo Horizonte and Recife, as well as smaller cities, carrying signs with ecological slogans, attacking President Jair Bolsonaro, whom they accuse of promoting the deforestation of the Amazon via his anti-environmentalist rhetoric, and expressing their commitment to the "Fridays for Future" movement led by Thunberg.
All in all, around the world some 5,000 marches and other protests were held in 150 countries within the framework of the "Global Climate Strike" to kick off a period of protests from Sept. 23-27 to demand action to deal with climate change and coinciding with the UN Climate Summit.
In Germany, organizers said more than 100,000 people turned out in Berlin, while major demonstrations were also held in other cities across the country.
More than 1,700 businesses closed for the day to let staff join the marches while students skipped classes in line with the traditional "Fridays For Future" protests pioneered by Thunberg.
By Friday morning, at least 1,000 students on strike had gathered in Foley Square in New York while similar marches were expected in over 1,100 different locations in the United States throughout the day.
Earlier in the day, crowds thronged the streets of Germany, where the government, led by Chancellor Angela Merkel, said it had finalized an ambitious agreement to tackle climate change.
The plan aims to allocate 54 billion euros of investment in energy, transport and development and reduce CO2 emissions by 55 percent by 2030.
Germany was planning to reduce emissions by 40 percent by 2020 but will not hit this target.
In London, crowds of students gathered in Westminster, the seat of the British government, holding posters and balloons.
London Mayor Sadiq Khan said on Twitter: "I stand in solidarity with everyone taking part in the Global Climate Strike."
He added that Prime Minister Boris Johnson must meet the demands by acting on the climate crisis immediately with "ambitious action."
Jeremy Corbyn, leader of the opposition Labour Party, said: "Young people and workers are coming out to say enough is enough. ... I'm proud to be joining London's largest climate crisis mobilisation to demand action."
Across Europe, youngsters have called on their governments to scale up action on climate change.
There were protests in Paris, Belgium, Helsinki, Copenhagen and many cities in between, including Stockholm, where Thunberg began her weekly school strikes before capturing the world's attention with her activism.
Thousands of people also protested across Africa, from Kenya to South African, Uganda to Nigeria.
Parts of the African continent are on the frontlines of the effects of climate change, with heightened risks of desertification, droughts and famine.
Although the continent is only responsible for 4 percent of the global carbon emissions output, six African countries are among the 10 most threatened by climate change, according to the African Development Bank.
They are Sierra Leone, South Sudan, Nigeria, Chad, Ethiopia, the Central African Republic and Eritrea.
"There is no distinction between social justice and environmental justice, the two have to be taken together. There are no human rights on a dead planet," Irungu Houghton, the director of Amnesty International in Kenya, said at the protest.
Irungu added that "rich Northern" countries should change their patterns of consumption to help tackle the global phenomenon.
Similar scenes were witnessed across Asia, the South Pacific and Australia earlier in the day.
Several cities in India, Pakistan and Bangladesh took part in the global strike against climate change on Friday.
In the city center of Indian capital New Delhi, hundreds of people, mostly students and youngsters, marched on the streets with slogans such as "there is no planet B" and banners saying "be part of the solution, not pollution".
"I am here to demand a change. Government sees resources and the environment as something which can be exploited but not conserved," said Vrushti, a teenager taking part in the Delhi protest.
According to a 2018 report by the World Health Organization, 14 Indian cities figure among the 18 most polluted cities in the world.
In Pakistan - a country which bears the brunt of natural disasters augmented by climate change such as desertification, droughts and floods - 33 cities, including capital Islamabad and major cities Lahore, Karachi and Peshawar, saw street protests organized by youngsters through social media.
Schoolchildren, teachers and parents gathered in the Australian city of Sydney holding placards that read "Time is running out," "Human change, not climate change", "There is no Planet B," and "If not now, when?"
Thousands also gathered in other cities around the country, such as Canberra, Melbourne and Hobart as part of a global event aimed at raising awareness among governments and companies of the need to curb climate change.
On the streets of the Australian capital, demonstrators called for "immediate action" while taking a swipe at Prime Minister Scott Morrison, for his position in favor of the coal industry.
Morrison, who is in the United States to meet President Donald Trump, will not attend the UN summit in New York on Monday, a gesture the Greens party described as "cowardice and contempt" given that Australia is one of the world's biggest greenhouse gas emitters.
Protests were also held in South Pacific island nations, which are among the most vulnerable to rising sea levels.
Schoolchildren on the Solomon Islands, some of them carrying shields and flags and others in canoes, gathered near the sea to demand action to tackle the climate crisis.
Meanwhile, students in Kiribati, with their fists held high, chanted "We are not sinking, we are fighting," according to images posted on Twitter by environmental non-profit 350.
Protesters came out in strength in the Thai capital, Bangkok, in Singapore and Indonesia's capital Jakarta.
The Youth Climate Summit will be held on Saturday, ahead of the UN Climate Change Summit, where only countries that have taken concrete steps to improve the environment will take the floor.