Buildings account for over half of most cities' emissions. Actions to make new and existing buildings more energy-efficient, clean up the energy they use, and minimize embodied emissions from construction are vital. Beyond buildings, it is a new model of urban development is needed. One that empowers local communities to adopt more sustainable lifestyles. In this session, two world-leading architects - Jeanne Gang, Founder and Leader of Studio Gang, and Kjetil Thorsen Trædal, Co-founder and Director of Snøhetta - will discuss with Hélène Chartier, Director of Urban planning and Design at C40, and will explain how they are transforming their practices to reduce the impact of their projects on the environment and to contribute to a better world.