Between 1970 and 2021, the number of people living in cities increased from 1.19 billion to 4.46 billion, while the Earth’s surface temperature climbed by 1.19 degrees Celsius above its preindustrial levels. Because of the prosperity they helped generate, cities have been a major cause of this climate change. However, it is also in cities that many of the solutions to the climate crisis—in terms of both adaptation and mitigation—will be found, not least because by 2050, almost 70 percent of the world’s population will call cities home. As such, cities are the key to arguably the greatest public policy challenge of our times. To take stock of how green, how resilient, and how inclusive cities globally are today, Thriving: Making Cities Green, Resilient, and Inclusive in a Changing Climate defines a global typology of more than 10,000 cities. It finds that there is wide variation in how green, resilient, and inclusive cities are around the world. It asks how climate change impacts cities and, conversely, how cities affect climate. Vicious cycles in development could occur as cities become more vulnerable to extreme events and the challenges compound and cascade. Finally, this report provides a compass for policy makers on policies that can help cities not only survive but also thrive in the face of the perils of climate change. Policy makers can and must act now to chart a more sustainable trajectory.