Leo Johnson is a Partner in PwC's Sustainability and Climate Change team, and Co-Founder of Sustainable Finance Ltd, now a part of the PricewaterhouseCoopers Group. His specialization is making business sense of sustainability, identifying environmental and social megatrends and the risks and opportunities for business leaders. Leo is a Business Fellow of the Smith School of Enterprise and Environment at Oxford, and a regular lecturer for Cambridge University's Programme for Sustainability Leadership. He has hosted the BBC World Show "Down to Business" helping scale up BBC World Challenges theworldchallenge.co.uk ground-breaking small businesses, including Green Gold in the Colombian jungle and biogas from waste in Kenya. He has commented and written guest columns for the BBC, CNN, CNBC, the Financial Times, and Wall Street Journal.

In his book "The Turnaround Challenge" (Oxford University Press, 2013), co-authored with Mick Blowfield, Leo moves beyond the rhetoric of extinction to look at the prospects for a next great wave of growth. Three cities of the future emerge as scenarios. The first is Petropolis, the city of fossil fuel driven mass production and consumption. The second is Cyburbia, sensored and censored. The third is the Distributed City, where post-mass technologies, from micro-production to renewable energy, help to construct a built environment in which we are not just resilient but thrive. smithschool.ox.ac.uk/leo-johnson

Follow Leo on twitter @Mr_LeoJ

In the spirit of ideas worth spreading, TEDx is a program of local, self-organized events that bring people together to share a TED-like experience. At a TEDx event, TEDTalks video and live speakers combine to spark deep discussion and connection in a small group. These local, self-organized events are branded TEDx, where x = independently organized TED event. The TED Conference provides general guidance for the TEDx program, but individual TEDx events are self-organized.* (*Subject to certain rules and regulations)