Stanford scientists are developing the tools for modeling the complex interactions of energy and the environment on a large scale. Integrated modeling is used to assess future environmental, energy and economic outcomes. Research topics include modeling the rise of shale gas production globally and its environmental and economic impacts. Another topic is the environmental consequences of global oil depletion and the transition to oil substitutes. Stanford researchers are also improving models for the interactions of policies on climate, local air quality and biofuels. Another example is the development of probabilistic and statistical tools for modeling the reliability of nuclear waste repositories.