With protesters gluing their hands to the floor and chaining themselves to cars, activist group Extinction Rebellion kicked off two weeks of global, peaceful protest on Monday (October 7).
In cities including London, Berlin, Amsterdam and Sydney, thousands of demonstrators blocked roads - calling for their governments to take urgent action to curb carbon emissions.
(SOUNDBITE) (English) PROTESTER, LIZZY MANSFIELD, SAYING: "... the government is not doing enough on the climate emergency.
And the keyword is emergency, right?
They declared an emergency after the rebellion in April and then we've seen like surprisingly little action.
So we're really here to push home this is an emergency.
We only get one planet and so we're here to try and defend it." The response from police was mass arrests.
By 1200 GMT there'd been more than 100 in London, 50 in Amsterdam and 30 in Sydney - though there were no arrests in Berlin.
In London, activists chained themselves to a mock nuclear missile outside the Ministry of Defense calling on the UK authorities to redirect funds spent on the Trident nuclear deterrent towards policies to combat climate change.
(SOUNDBITE) (English) CLIMATE CHANGE ACTIVIST, JAKE LYNCH, SAYING: "We're still subsidizing fossil fuels, more than any other countries in Europe, globally carbon emissions are still increasing, we're heading in precisely the wrong direction.
We here at Extinction Rebellion are taking action to interrupt the flow of normality because it is that flow that is carrying us towards disaster." It was in London where Extinction Rebellion gained prominence after the group disrupted traffic in central London for 11 days in April.
More than 1,000 activists were arrested.
This time, police are adopting more proactive tactics, mobilizing thousands of officers and saying that anyone who breaks the law, even through non-violent, civil disobedience, will be arrested.
On Saturday (October 5) officers used a battering ram to enter a building in south London where activists had been storing materials to use during the protests.
Extinction Rebellion said the police response shows that British authorities consider them to be a significant movement.