MIT Technology Review: Amid the crises and battles, both predictable and unforeseeable, that you will face over the next four years, one problem will stand out both for the economic and social dangers it poses and for the difficulty and cost of solving it. Whether you can develop a practical and sustainable strategy to address climate change--specifically, to begin lowering carbon dioxide emissions--will define the success of your new term as president. We do not make such a declaration lightly; we are keenly aware of...