Ban Ki-moon
UN Secretary-General Ban Ki-moon speaks at a conference ahead of the 69th UN General Assembly in New YorkReuters

Thousands are expected to take to the streets in New York City and around the world in the largest campaign over climate change in history this weekend.

Over 1,400 different organisations will be represented at the People's Climate March in NYC alone, ranging from faith-based groups to unions and businesses. The protest, taking place on Sunday 21 September, will feature art installations, music and other activities, all in the name of environmental justice.

What is the march all about?

The march has been organised to generate public pressure in advance of the United Nations Climate Summit on 23 September. World leaders are coming to NYC for the summit on the climate crisis, and UN Secretary-General Ban Ki-moon is urging governments to support an ambitious global agreement to dramatically reduce global warming pollution.

Devised as part of a build-up to the Paris climate negotiations in 2015, the march is aimed to show the backing of the agreement from the people, to demand action on reducing climate change. It is aimed at promoting a healthy planet and economy and representing the communities that are being hit the hardest by climate change.

Leading artists, athletes and influencers are helping to spread the word about the People's Climate March, from Evangeline Lilly to Seth Rogan.

"The People's Climate March can be – and in many ways already is – creating a tipping point moment for the world," a statement from the organisers reads. "There's real power in this kind of human energy."

Climate change
New York skyline after the lights were turned off during Earth Hour to support climate change action in 2013Reuters

What will the agreement do?

Over 100 heads of state will attend next week's summit, to secure the next big step in the fight against climate change – an international agreement on greenhouse gas reductions. Obama. The idea is to secure an international pact, rather than a formal treaty.

The summit will also focus on limiting deforestation and mobilising financial support for action on the climate.

According to the International Energy Agency, the world must invest at least an additional one trillion dollars per year – known as the "clean trillion" – into clean energy by 2050. By doing so, it is hoped this will limit global warming to 2 degrees Celcius above pre-industrial temperatures, avoiding the worst impacts of climate change on Earth's environment.

Yet UN officials have said global investment in clean energy was just 254 billion dollars in 2013.

Where is the march in NYC?

The march will begin at 11.30am on Sunday 21 September at Central Park West, between 65th and 86th streets. The route will take crowds east to 59th Street, onto 6th Ave and onto 42nd Street, eventually ending on 11th Ave. For the full route and a map, click here.

It is expected to draw in 100,000 protesters from around the country.

What is going on elsewhere?

Beyond New York, there will be different climate-related marches and events happening in every continent over the weekend.

Around 2,000 events are taking place in 150 countries, from people marching to submerged lighthouses on the New Guinea coast to people holding hands across the US-Canadian border. There are also marches in London, Delhi, Melbourne, Rio de Janeiro and Jakarta.