This roulette wheel depicts the probability of potential global warming over the next hundred years in a scenario in which policies are enacted to reduce emissions. In contrast to the reference case, in which global anthropogenic greenhouse gas emissions are assumed to continue to increase unabated, the policy case reduces the estimated range of potential warming, and decreases the chance of large degrees of warming. The particular policy scenario considered by the MIT Joint Program for this estimation comes close to stabilizing the atmospheric concentration of carbon dioxide at 550 parts per million after the year 2100.