For over a decade, Steve has led a research group dedicated to quantifying how different human activities are affecting climate and air quality, how those environmental changes in turn jeopardize human wellbeing, and the relative priority of solutions. In that time he and his group have published seminal papers assessing carbon emissions and air pollution impacts embodied in international trade, committed emissions related to existing energy infrastructure, the economic and biophysical limits of various carbon removal approaches, interactions among food-energy-water systems, global and regional drivers of agriculture land-use change emissions, and opportunities and challenges for net-zero emissions energy systems.

While Head of Climate Science, Steve led Watershed’s carbon experts developing methodologies to measure customers’ emissions and help prioritize their decarbonization efforts. This included vetting reduction and removal options offered in the Watershed Marketplace. As chair of Watershed's Science Advisory Board, Steve convenes and engages a group of top experts in GHG accounting, climate mitigation, and carbon removal on behalf of the company.