Danish police say they’ve arrested nearly a thousand people during mass protests on the fringes of the climate change summit in Copenhagen. Many of them are said to be members of the Black Blocs group, an organisation which advocates violent direct action and which disrupted the NATO summit in France in April. They’ve threatened unspecified protests next week when world leaders join the summit.Tens of thousands of protesters from all over the world travelled to Denmark to demand political leaders do something urgently to save the planet. The main demonstration featured dancers, drummers and banners saying: “There is no planet B” and “Change the politics, not the climate”. Organisers claimed 100,000 people took part in the march, hoping their rally and others round the world on a global day of action will put pressure on the summit to agree a deal next week.