Striking students tell world leaders 'do your jobs' on climate

Hundreds of thousands of students, office workers and other protesters took to the streets across the globe on Friday to demand urgent action to avert an environmental catastrophe from world leaders gathering for a UN climate summit.

The global climate strike kicked off in the Pacific islands - some of the nations most threatened by rising sea levels - and followed the rising sun through Australia, Japan, Southeast Asia and into Europe and Africa.

Greta Thunberg, the 16-year-old Swedish activist who has inspired the movement, noted the "huge crowd" in Sydney in a tweet, which she said would set the standard for strikes and protests planned in about 150 countries worldwide.

Social media posts showed huge demonstrations across Australia, from the big coastal cities of Sydney and Melbourne to outback towns such as Alice Springs.

Organisers and police gave differing numbers for those taking part, but the Australian Broadcasting Corp said 180,000 would be a conservative estimate of participants nationwide.

"The oceans are rising and so are we," read one sign held by a protester wearing school uniform in Melbourne.

By mid-morning across Europe and Africa, crowds had gathered in many cities, including London, Berlin, Warsaw and Nairobi.

"We are skipping our lessons to teach you one," read a placard carried by a student in London.

The protesters are calling on governments to take immediate action to limit the harmful effects of manmade climate change.

The strike will culminate in New York when Thunberg, who has been nominated for a Nobel Peace Prize for her climate activism, will spearhead a rally at the United Nations headquarters.

Danielle Porepilliasana, a Sydney high school student, had a blunt message for politicians such as Australian Finance Minister Mathias Cormann, who told Parliament on Thursday that students should stay in class.

"World leaders from everywhere are telling us that students need to be at school doing work," she said, wearing anti-coal earrings. "I'd like to see them at their Parliaments doing their jobs for once."

Global warming caused by heat-trapping greenhouse gases from burning fossil fuels has already led to droughts and heatwaves, melting glaciers, rising sea levels and floods, scientists say.

Carbon emissions climbed to a record high last year, despite a warning from the UN-backed Intergovernmental Panel on Climate Change in October that output of the gases must be slashed over the next 12 years to stabilise the climate.

Organisers said demonstrations would take different forms around the world, but all aim to promote awareness of climate change and demand political action to curb contributing factors.

The protest movement is putting increasing pressure on both governments and companies to respond.

Online retail giant Amazon.com Inc pledged on Thursday it would be net carbon neutral by 2040 and would buy 100,000 electric delivery vans from a start-up firm.

Cutting emissions is a challenging goal for Amazon, which delivers 10 billion items a year and has a massive transport and data centre footprint. "We know we can do it and we know we have to do it," Chief Executive Officer Jeff Bezos said.

Environmental advocacy group Greenpeace USA welcomed the commitment, but a spokesman said the company lagged peers Google, Apple and Facebook in transparency around its renewable projects.

Some of the company's workers from the group Amazon Employees for Climate Justice plan to join marches on Friday.

In Europe, German Chancellor Angela Merkel was due to unveil a major new climate protection package thrashed out by parties in her coalition in all-night talks. Meanwhile, on the streets of the capital, crowds gathered at the Brandenburg Gate, where three activists stood on blocks of ice beneath mock gallows.

The UN summit brings together world leaders to discuss climate change mitigation strategies, such as transitioning to renewable energy sources from fossil fuels.

The issue is vital to low-lying Pacific islands, which have repeatedly asked wealthier nations to do more to prevent rising sea levels.

As Friday's day of action got underway across scattered Pacific communities, students holding placards in Kiribati chanted: "We are not sinking, we are fighting". Children in the Solomon Islands rallied on the shoreline wearing traditional grass skirts and carrying wooden shields.

Hours later in Thailand, more than 200 young people stormed the Environment Ministry and dropped to the ground feigning death.

"This is what will happen if we don't stop climate change now," said 21-year-old strike organiser Nanticha Ocharoenchai.

In Kenya, around 500 activists marched through the streets demanding that the government cancel plans for a coal plant and investigate corruption in hydropower dams.

"In Samburu there is a lot of heat, the grass has dried up, there is little water," said Francis Lentel, a young herdsman in traditional beads, holding a picture of the earth weeping.

In India's financial capital Mumbai, battered this year by a heavier-than-usual monsoon that caused flooding, children from at least 10 schools joined protests throughout the day.

Children in the eastern city of Kolkata handed out flyers at busy bus terminals. "This is the only planet we have," one of the children said.