Bill Weihl, PhD, is currently director of sustainability at Facebook. His group manages sustainability and energy efficiency across the company, driving projects to track and reduce the company’s environmental footprint in all aspects of its operations. They also work collaboratively with other companies to scale sustainability solutions across the IT industry and into other industries. As a Hertz Fellow at MIT, Bill earned a PhD in computer science in 1984. He was professor of computer science at MIT for ten years, receiving tenure in 1992, and leaving for industry in 1994. Building upon his success in the technology industry, Bill focused on renewable energy, climate change, and environmental issues starting in 2005. In 2006, he joined Google, as Green Energy Czar. In 2009, he was honored by Time magazine as one of their “Heroes of the Environment” in recognition of the work he and his colleagues did at Google. He joined Facebook in early 2012.