I have worked as an energy and environmental systems analyst since the early 1980s—from local to global scales. My specialties are energy efficiency in buildings and industry and the intersection of energy technology, global climate change impacts, and risk management. I received a Masters of Science degree from the Energy and Resources Group (where I am now a Research Affiliate) at the University of California at Berkeley in 1987 and a Ph.D. from the Department of Environmental and Energy Systems Studies under Thomas B. Johansson at the University of Lund in Sweden in 1991.

In the early 1980s at Berkeley, I studied and taught about green buildings with Sim van der Ryn before they were in vogue. In Sweden, I worked closely with the Swedish State Power Board and the Swedish National Board for Industrial and Technical Development on energy planning projects. I am currently with the U.S. Department of Energy's Lawrence Berkeley National Laboratory, a world-class research center on energy and environment with a staff approximately 500 people and consult widely for private industry and the public sector. I collaborated for many years at LBNL with Art Rosenfeld, including as his Deputy Director of the Center for Building Science, later leading the Center. I've published over 200 articles and reports in my fields of interest, and recently participated in the U.S. Climate Change Program's national assessment entitled "Global Climate Change Impacts in the United States."

I am a member of the international body of scientists which as worked over the past two decades under the Intergovernmental Panel on Climate Change (IPCC), which collectively shared in the Nobel Peace Prize for 2007 with former U.S. Vice President Albert Arnold (Al) Gore Jr. "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change."