Cities and citizens are joining the challenge of climate change by developing actions at the city level. By doing this, cities (and their citizens) complement national governments or even fill the gap left by their government’s absence or failure to act against climate change. In the next video, associate professor Jeroen van der Heijden will explain how cities engage with their citizens in such actions and how this has an impact, not only at a local level, but also globally via the potential collaborations between different cities around the world.