'I am marching for my children': Hollywood stars Leonardo DiCaprio and Mark Ruffalo join thousands crowding NY streets for largest climate change protest ever

• Roughly 100,000 filled the streets of NYC for the People's Climate March in midtown Manhattan ahead of Tuesday's United Nations hosted summit on carbon emissions
• United Nations Secretary-General Ban Ki-moon, former vice president Al Gore, New York City Mayor Bill de Blasio, and U.S. senators also joined the march
• Similar rallies were held around the world including Britain, France, Afghanistan, and Bulgaria

An international day of action on climate change brought tens of thousands onto the streets of New York on Sunday, with organizers predicting the biggest protest on the issue for five years.

Some 100,000 people, including United Nations Secretary-General Ban Ki-moon, New York City Mayor Bill de Blasio and U.S. senators were expected to join the People's Climate March in midtown Manhattan, ahead of Tuesday's United Nations hosted summit in the city to discuss reducing carbon emissions that threaten the environment.

Organizers said some 550 busloads had arrived for the rally, which followed similar events in 166 countries including Britain, France, Afghanistan and Bulgaria.

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Actor Leonardo DiCaprio (C) walks down 6th Avenue during the the People's Climate March

The march was due to step off around 11:30 a.m. ET, covering a 2-mile route winding past Times Square

Former U.S. Vice President and environmental activist Al Gore also joined in the massive gathering

'Today I am marching for my children. I am marching so they can live in a world without worrying about the next big storm destroying their community,' said Bill Aristovolus, the superintendent of an apartment building in New York City's working-class Bronx borough.

 

A crowd including U.S. senators Bernard Sanders of Vermont and Sheldon Whitehouse of Rhode Island lined up along a mile long stretch along New York's Central Park, bearing signs reading 'stop tar sands' and 'keep the oil in the ground.'

Actor and activist Mark Ruffalo takes questions before the start of the People's Climate March in New York Sunday

Demonstrators make their way down Sixth Avenue past Radio City Music Hall as they demanded action on climate change

Marchers carried pictures of sunflowers and, at the rally's head, a banner reading 'front lines of crisis, forefront of climate change.'

The march was due to step off around 11:30 a.m. ET, covering a 2-mile route winding past Times Square.

Organizers billed the event as the largest gathering focused on climate change since 2009, when tens of thousands gathered in Copenhagen in a sometime raucous demonstration that resulted in the detention of 2,000 protesters.

Marchers carried pictures of sunflowers and, at the rally's head, a banner reading 'front lines of crisis, forefront of climate change'

Sting (C) was part of the march due to step off around 11:30 a.m. ET, covering a 2-mile route winding past Times Square

Activists hold placards while taking part in the People's Climate March through Midtown, New York

De Blasio on Sunday unveiled a new plan for the city to reduce its greenhouse gas emissions by 80 percent from 2005 levels by 2050.

All 3,000 major city-owned buildings would be retrofitted with energy saving heating, cooling and light systems by then, he said, though meeting the commitment will also require significant investments by private landlords.

Musician Sting (2nd R) joins the People's Climate March

The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists

Besides Leo, the crowd included U.S. senators and enough people to line up along a mile

'Climate change is an existential threat to New Yorkers and our planet,' de Blasio said. 'Acting now is nothing short of a moral imperative.'

Protests were also taking place in Brussels, Belgium; New Delhi, India; Istanbul, Turkey; and Sydney and Melbourne, Australia.

Actress Emma Thompson speaks to the media at the start of the 'People's Climate March' in central London September held on the same day as New York's rally

Peter Gabriel also joined 40,000 marchers in London

Forty thousand campaigners were marching in London today to demand urgent action on climate change.

Celebrities in the United Kingdom including actress Emma Thompson and musician Peter Gabriel are joining campaigners and British flood victims at the march and rally.

Ahead of the march in central London, Miss Thompson said: ‘Every single person on this earth has the power to change the world.

‘And when we all come together, our power becomes irresistible. Together we have built countries and cultures and technologies.’