Cities around the world play a big role in reducing greenhouse gas emissions. A study looked at 167 cities and their efforts to cut carbon pollution. They found that cities in developed countries have higher emissions per person than those in developing countries. Buildings and transportation are the main sources of emissions. Developed cities aim for absolute carbon reduction by 2050, while developing cities focus on reducing emissions per unit of economic output. To meet global climate goals, cities need to set more ambitious targets and take stronger actions to cut emissions.