Cities are at the frontline in tackling climate change. By 2050, 68% of humanity will live in cities. This will increase energy consumption, infrastructure demand, and carbon emissions. The planet urgently needs urban decarbonisation solutions. The good news is that we don't have to wait for innovation, the technologies already exist, and we can take action now. The World Economic Forum’s Net Zero Carbon Cities Program highlights such proven solutions to energy efficiency, clean electrification, and material circularity in urban systems. At COP27, the World Economic Forum and its partners will launch the Net Zero Carbon Cities Toolbox. Here’s what it might look like.