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In the process of development of human settlements, urbanization is the dominant trend in last several decades and will continue to be so. There are several drivers in this process such as demographic, social, economic, trade and institutions. Urban areas generate more than 90% of global economy (high agreement, much evidence).

Urban settlements contribute significantly to the total GHG emissions. Urban areas account for about 70% energy related total CO2 emissions based on production side allocation of CO2 emissions including emissions during electricity generation that are consumed in cities. If CO2 emissions are allocated to consumption side of goods and service then urban areas’ contribution is expected to be higher. Estimates of urban contributions to GHG emission vary due to variations in the definition of urban by country and study, and different emission allocation principles. When normalized by urban population, per capita emissions of urban areas are almost always lower than national averages in developed countries while there are indications for the opposite relation in developing countries due to factors such as income and energy mix structure (high agreement, much evidence). There is no consensus on the best approach to account for urban GHG emissions and there is a need for standardized methodologies for city-level carbon accounting.