Greg Rau of UC Santa Cruz cast the mandatory pall-of-the-day with a blunt assessment of the battle against global warming: “We are failing to mitigate atmospheric CO2.” Too much of growing energy demand is being met with fossil fuels, Rau explained. “We need to urgently think about this.” Most of Rau’s talk was devoted to the problem of ocean acidification, recently profiled by my colleague Lauren Sommer for Quest Radio.

One guy who’s done a lot of thinking about it is Hashem Akbari, who will take the lectern today to call upon cities around the world to move rapidly toward “cool roof” policies. Akbari, who works at Lawrence Berkeley National Lab, has been a long-time advocate of using reflective roofing and paving materials to help offset the effect of “urban heat islands.” He says that replacing the roof of one typical suburban home (about 1,000 square feet) can produce a CO2 “offset” of four metric tons. He adds that replacing flat commercial roofing with white “cool” roofing or coatings can increase the solar reflectance of the roof from as low as 10% to as high as 80% (at least until it gets dirty). I  interviewed Akbari for a Quest Radio piece on heat islands last year.