The Urban Expansion program provided technical support to the Coalition for Urban Transitions (CUT) to inform the COP26 (UN Climate Change Conference of the Parties) process. Building off analysis provided for the 2019 CUT report, Climate Emergency, Urban Opportunity, the new report, Seizing the Urban Opportunity, uses data produced by the Urban Expansion program to build the case for how governments can tackle the climate crisis and secure shared prosperity through cities’ development. The team calculated the conversion of land to urban use in the recent past by applying its settlement-extent methodology to the entire world. This analysis fuses the Urban Expansion program’s methods and the European Commission’s Global Human Settlement Layer. It provides new information on the amount and shares of land converted to urban use in all countries and major regions and on the type of land cover that was converted to urban use, such as cultivated land, forest, grassland, and wetland. Further information can be found in the report’s technical annexes.