Cities are vital to the world's economies and play a key role in combating climate change. They are responsible for 40% of total energy consumption and up to 70% of greenhouse gas emissions according to a recent report by Deloitte. How can we make cities more sustainable? That's a question that Kiran Bhatraju, CEO and Founder of Arcadia and Maisie Hughes, Senior Director of Urban Forestry, American Forests try to answer this week in a discussion moderated by Nick Lichtenberg, Executive News Editor at Fortune Magazine.