"Thinking about tipping provides a novel perspective on finding a way forward in climate negotiations and suggests an alternative to the current framework of negotiating a global agreement on reductions in greenhouse gas emissions. Recent work on non-cooperative games shows games with increasing differences have multiple equilibria and have a "tipping set," a subset of agents who by changing from the inefficient to the efficient equilibrium can induce all others to do the same. We argue that international climate negotiations may form such a game and so have a tipping set. This set is a small group of countries who by adopting climate control measures can make in the interests of all others to do likewise"--National Bureau of Economic Research web site.