Young people around the world took to the streets on Friday to demand urgent action to avert disastrous climate change, in their largest protest since the start of the COVID-19 pandemic. The strike takes place five weeks before the U.N. COP26 summit, which aims to secure more ambitious climate action from world leaders to drastically cut the greenhouse gas emissions heating the planet. “The concentration of CO2 in the sky hasn’t been this high for at least 3 million years,” Swedish activist Greta Thunberg told a crowd of thousands of protesters in the German capital. “It is clearer than ever that no political party is doing close to enough.” Demonstrations were planned in more than 1,500 locations by youth movement Fridays for Future, kicking off in Asia with small-scale demonstrations in the Philippines and Bangladesh, and spreading throughout the day to European cities including Warsaw, Turin and Berlin. “Everyone is talking about making promises, but nobody keeps their promise. We want more action,” said Farzana Faruk Jhumu, 22, a youth climate activist in Dhaka, Bangladesh. “We want the work, not just the promises.” A landmark U.N. climate science report in August warned that human activity has already locked in climate disruptions for decades – but that rapid, large-scale action to reduce emissions could still stave off some of the most destructive impacts.