Members of the climate activist group, Extinction Rebellion, have called for days of protest across London.

The group has blocked four main traffic arteries in central London since Monday, and on Wednesday it began a day of disruption of the city's overground train network. London's Metropolitan Police confirmed that it has made more than 500 arrests since Monday in relation to the protests.

Founded by British activists, Extinction Rebellion has three stated aims: to get governments to declare a "climate emergency"; to reduce net greenhouse gas emissions to zero by 2025; and for citizens' assemblies to lead the government on climate and ecological justice.

Police carry a protester away from Oxford Circus on April 17.
Police carry a protester away from Oxford Circus on April 17.
Tolga Akmen/AFP/Getty Images
Activists blockade Waterloo bridge on the third day of protests organized by the Extinction Rebellion group.
Activists blockade Waterloo bridge on the third day of protests organized by the Extinction Rebellion group.
Tolga Akmen/AFP/Getty Images
Activists, including Labour Party councilor Skeena Rathor, left, are photographed with their hands glued together and locked to a fence outside the home of Labour Party leader Jeremy Corbyn in north London on April 17.
Activists, including Labour Party councilor Skeena Rathor, left, are photographed with their hands glued together and locked to a fence outside the home of Labour Party leader Jeremy Corbyn in north London on April 17.
Daniel Leal-Olivas/AFP/Getty Images
Police begin to remove climate activists who glued themselves to a train in London on April 17.
Police begin to remove climate activists who glued themselves to a train in London on April 17.
Kirsty O'Connor/AP
Climate activists hold a sign on top of a Dockland Light Railway train at Canary Wharf station, in east London, as part of ongoing climate change protests in the English capital.
Climate activists hold a sign on top of a Dockland Light Railway train at Canary Wharf station, in east London, as part of ongoing climate change protests in the English capital.
Henry Nicholls/REUTERS
Activists block Oxford Circus in central London on Wednesday.
Activists block Oxford Circus in central London on Wednesday.
Daniel Leal-OlivasAFP/Getty Images
A climate change protestor who glued his hand to a window halts a train at Canary wharf station on the third day of environmental protests by the Extinction Rebellion group.
A climate change protestor who glued his hand to a window halts a train at Canary wharf station on the third day of environmental protests by the Extinction Rebellion group.
Daniel Leal-Olivas/AFP/Getty Images
Climate change protestors practice yoga on Waterloo Bridge in central London on April 17.
Climate change protestors practice yoga on Waterloo Bridge in central London on April 17.
Tolga Akmen/AFP/Getty Images
A boy plays football across chalk drawings during the ongoing blockade of Waterloo Bridge.
A boy plays football across chalk drawings during the ongoing blockade of Waterloo Bridge.
Frank Augstein/AP
Police officers remove a protester from the Waterloo Bridge blockade during a coordinated protest on Tuesday, April 16.
Police officers remove a protester from the Waterloo Bridge blockade during a coordinated protest on Tuesday, April 16.
Leon Neal/Getty Images
Activists carry model insects as the demonstrate on Waterloo Bridge on April 16.
Activists carry model insects as the demonstrate on Waterloo Bridge on April 16.
Daniel Leal-Olivas/AFP/Getty Images
A infant is held alongside a protest sign in Parliament Square, London, on Tuesday.
A infant is held alongside a protest sign in Parliament Square, London, on Tuesday.
Kirsty O'Connor/PA Images via Getty Images
Members of the Extinction Rebellion group talk with police during a demonstration at Waterloo Bridge.
Members of the Extinction Rebellion group talk with police during a demonstration at Waterloo Bridge.
Tayfun Salci/Anadolu Agency/Getty Images
"No Time to Waste" is written on the pavement at Waterloo Bridge.
"No Time to Waste" is written on the pavement at Waterloo Bridge.
Richard Baker/In Pictures via Getty Images
Extinction Rebellion demonstrators camp near Marble Arch, London, on April 16.
Extinction Rebellion demonstrators camp near Marble Arch, London, on April 16.
Yui Mok/PA Images via Getty Images
An activist sprays graffiti on an awning at the Shell Centre, offices of Royal Dutch Shell, as demonstrators surround the building during an environmental protest by Extinction Rebellion members on Monday, April 15.
An activist sprays graffiti on an awning at the Shell Centre, offices of Royal Dutch Shell, as demonstrators surround the building during an environmental protest by Extinction Rebellion members on Monday, April 15.
Tolga Akmen/AFP/Getty Images
A campaigner sits with her hand glued to the revolving doors at the entrance to the Shell Oil building on April 15.
A campaigner sits with her hand glued to the revolving doors at the entrance to the Shell Oil building on April 15.
Dan Kitwood/Getty Images
Protesting acrobats block traffic in London on April 15.
Protesting acrobats block traffic in London on April 15.
Richard Baker/In Pictures via Getty Images
Members of the Extinction Rebellion group stage a demonstration on Waterloo Bridge.
Members of the Extinction Rebellion group stage a demonstration on Waterloo Bridge.
Tolga Akmen/AFP/Getty Images
Ice blocks shaped as life vests melt in the sun as members and supporters of Extinction Rebellion rally in Parliament Square on April 15.
Ice blocks shaped as life vests melt in the sun as members and supporters of Extinction Rebellion rally in Parliament Square on April 15.
David Cliff/NurPhoto via Getty Images
Demonstrators wear costumes at Oxford Circus.
Demonstrators wear costumes at Oxford Circus.
Daniel Leal-Olivas/AFP/Getty Images
An environmental protestor stands on a barrier to take a picture on April 15.
An environmental protestor stands on a barrier to take a picture on April 15.
Tolga Akmen/AFP/Getty Images
Acrobats participate in the demonstration at Oxford Circus on April 15.
Acrobats participate in the demonstration at Oxford Circus on April 15.
Daniel Leal-Olivas/AFP/Getty Images
Environmental protesters from the Extinction Rebellion group arrive with a tree to stage a demonstration on Waterloo Bridge. Protesters placed plants along the length of the bridge on April 15.
Environmental protesters from the Extinction Rebellion group arrive with a tree to stage a demonstration on Waterloo Bridge. Protesters placed plants along the length of the bridge on April 15.
TOLGA AKMEN/AFP/Getty Images