With collaborators Humberto Llavador and Joaquim Silvestre, Roemer has elaborated a formal theory of sustainability, which the authors apply to the problem of climate change (Llavador, Roemer, and Silvestre 2010 and 2011).[1] Rather than maximizing a sum of discounted generational utilities into the future, which is the virtually ubiquitous practice of economists working on climate change, the authors maximize an objective which sustains welfare at the highest feasible level, or sustains growth in welfare at a chosen growth rate. Roemer (2011) critiques the discounted utilitarian approach.