In The Urban Revolution (1970), Lefebvre begins: "the society has been completely urbanized". As provocative as it may sound, urbanization has been one of the most influential drivers of political and economic systems since 1980s. The contemporary environmental geography and environmental policy literature just recently started to underline the importance of urbanization and its environmental consequences. This lecture's aims are threefold: firstly, exploring urbanization, as an analytical and a spatial category, with its impacts on environmental systems. Here, I exploit the conceptual opportunities and tools that the critical urban studies offer for understanding such impacts. The second part of the lecture will examine the realm of the social with a close attention to power relations to understand the urban scale in human-environmental processes. The last focus will briefly open the floor for a debate on the interdisciplinary work that can actually decipher the initial question of: "What kind of an urban geography for what kind of an environmental policy?"