PARIS/PERTH (REUTERS) - Hundreds of thousands of people from Australia to Paraguay joined the biggest day of climate change activism in history on Sunday (Nov 29), telling world leaders gathering for a summit in Paris there is "No Planet B" in the fight against global warming.
More than 2,000 events were held in cities including London, Sao Paulo, New York and Asuncion, Paraguay, as well as Paris itself, on the eve of the summit which runs from Monday (Nov 30) until Dec 11 and will be attended by about 150 heads of government.
"Over 570,000 people called with one voice for global leaders to deliver a 100 per cent clean energy future at the Paris summit," said Ms Emma Ruby-Sachs, campaign director of Avaaz, one of the organisers.
Around the world, activists marched, dressed as polar bears or penguins at risk from melting ice, or chanted slogans such as"climate justice".
Organisers said that 570,000 people so far had taken part in rallies worldwide and that they expected demonstrations including in Ottawa and Mexico City later in the day to push the count above 600,000. "These are the biggest set of global marches in history," said Mr Sam Barratt at Avaaz.
There was no independent verification of the numbers, although none of the individual marches rivalled one in New York last year that drew an estimated 310,000 people.
In Sydney, about 45,000 people are estimated to have marched through the central business district towards the Opera House. Protesters held placards reading: "There is no Planet B", and"Say no to burning national forests for electricity".
In London, organisers said 50,000 marchers were joined by fashion designer Vivienne Westwood, actress Emma Thompson and opposition Labour leader Jeremy Corbyn, who said the turnout was especially impressive for a wet November Sunday.
Almost all the demonstrations were peaceful, but riot police fired tear gas and clashed with about 200 protesters in Paris, some wearing masks, in the Place de la Republique. The demonstrators had carried banners calling for the defence of the climate and democracy.
US President Barack Obama and China's Xi Jinping will be among the leaders attending the start of the summit, which organisers hope will produce a legally binding agreement to commit both rich and developing nations to curbing emissions of greenhouse gases, blamed for warming the planet, beyond 2020.
Hopes are high that the Paris summit will not fail like the previous such meeting six years ago in Copenhagen.
Popular and political momentum for tougher action on carbon emissions has accelerated in recent years, with 2015 set to be the warmest on record. Activists are seeking to combat everything from Beijing's smoggy skies to Canada's Keystone oil pipeline.
Ms Saiba Suso, a 26-year-old demonstrator in Paris, said the poor were most at risk: "We are paying the price and we are not the cause. The industrialised countries owe us a lot."
Still, all sides say pledges made in Paris will be insufficient to limit a rise in global temperatures to 2 deg C above pre-industrial levels, widely viewed as a threshold for dangerous changes in the planet's climate system.