Who has the better sustainability profile, a vegetarian who drives a Hummer or a meat-eater who drives a Prius? Is it always better to buy local produce? Is a new innovation – really “more sustainable” than the existing alternative in the grand scheme of things? The answers are complicated. The reality is that people make choices daily around what they perceive to be a more sustainable option, but the real answer is often not intuitive. In this AMA, we’d like to talk about the concept of life cycle thinking as a framework for understanding sustainability holistically. We have spent our careers assessing the products people make or buy, from raw materials to end-of-life, from “cradle to grave.” We will discuss Life Cycle Assessment, a specific science that measures the mass and energy flows to determine the potential impact of “stuff.” There are also simpler tools that you can use to incorporate life cycle thinking into a much broader range of decisions – from questions around R&D investments, to what to buy the next time you stop at the store. RICH HELLING: I am chemical engineer (Sc.D. from MIT) and the Director of Sustainable Chemistry at Dow. I have been with the company for nearly 30 years, and for the last decade, I have concentrated on how to use life cycle thinking – in particular applying LCA and related tools to identify opportunities for innovation and to differentiate new products in the marketplace. I have authored 23 papers and hold two patents. I am a certified LCA Professional, a member of Michigan’s Green Chemistry Roundtable and active in working groups of The Sustainability Consortium. HAN ZHANG: I am the Sustainability and Advocacy Manager for one of Dow’s business units and have extensive experience managing the company’s sustainability reporting, including publication of our Global Reporting Index (GRI) G4 Annual Sustainability Report and annual submissions to the Dow Jones Sustainability Index. Previously, I worked in life cycle assessment, biofuels development and strategic implementation of alternative energy plans in the energy industry. I hold a PhD from the University of Michigan’s School of Natural Resources and the Environment, as well as master’s and bachelor’s degrees in thermal engineering from Tsinghua University in China. We will be back at 1 pm ET (10 am PT, 5 pm UTC) to answer your questions, ask us anything! Thanks for the many questions and the great discussions! It’s great to see the excitement and insights about life cycle and sustainability topics. We have to go now, but will try to get back to some of the questions!