This chapter explores to paint a picture of what a future low carbon world might look like and in particular describe the role and fate of cities in such a world. Along with innovation and human capital, infrastructure is seen as a key component of the OECD's framework for urban green growth, leading to green jobs, green supply and consumption, and urban attractiveness. The OECD has estimated future costs in other infrastructure sectors, which turn out to be quite important due to their financial and technological interactions with the sectors covered by the IEA. The IEA describes and costs out a possible scenario for the energy-related infrastructure that going forward would be required to limit global climate change to 2 Centigrade degrees. Many organizations have recognized the key role of cities in reducing global greenhouse gas (GHG) emissions, but this chapter first wants to go beyond discussing low carbon cities and consider a low carbon planet.