Tag Archives: cool pavements

New Energy & Buildings paper highlights cool communities in CA and beyond

A new paper now in press in Energy and Buildings highlights local and state initiatives to advance cool roofs, cool pavements, and urban vegetation in California and beyond.

In particular, the paper reviews efforts that two of California’s largest school districts have undertaken to deploy cool community measures to keep schoolyards cooler and reduce energy bills. The paper also updates how cool community measures are being included as components of local climate action and adaptation plans and of California’s statewide guidelines for extreme heat adaptation.

You can download the full paper through ScienceDirect here.

In 2006, California introduced the Global Warming Solutions Act (Assembly Bill 32), which requires the state to reduce greenhouse gas emissions to 1990 levels by 2020. “Cool community” strategies, including cool roofs, cool pavements, cool walls and urban vegetation, have been identified as voluntary measures with potential to reduce statewide emissions. In addition, cool community strategies provide co-benefits for residents of California, such as reduced utility bills, improved air quality and enhanced urban livability. To achieve these savings, Lawrence Berkeley National Laboratory (LBNL) has worked with state and local officials, non-profit organizations, school districts, utilities, and manufacturers for 4 years to advance the science and implementation of cool community strategies. This paper summarizes the accomplishments of this program, as well as recent developments in cool community policy in California and other national and international efforts. We also outline lessons learned from these efforts to characterize successful programs and policies to be replicated in the future.

Climate Change and Geoengineering

There has been a lot of press coverage of the decision by the National Academy of Science to study the feasibility and safety of large-scale geoengineering as a means to address climate change. It is hard to believe that we are at a stage where we must consider such drastic strategies.

Much of the conversation has revolved around the idea of albedo modification — that is, increasing the amount of solar energy reflected into space rather than absorbed by earth. Conceptually, this is the same process that keeps light colored roofs and pavements cooler. However, the scale of the geoengineering being considered is staggering — we are talking huge swaths of the earth brightened by man-made clouds. Since only 1% of earth’s surface is urban, even a wildly successful global cool roofs and pavements campaign would be nearly 70 times smaller in scale than what is under study now. There really is no comparison.

And yet, focusing efforts of deploying more cool roofs and pavements would have a tremendously positive impact on the planet. They help cut cooling energy and peak electricity demand, improve heat resiliency of people living in unconditioned buildings, and cool down communities and help reduce air pollution; all while safely offsetting the warming effect of atmospheric greenhouse gases.

The scientific debate is on about whether we have reached a point where we must consider drastic measures to combat climate change. Either way, we should be taking the simple and affordable first steps to improve our buildings, communities, and planet by installing cool roofs and pavements anywhere it makes sense to do so.


On November 6th, I gave a talk at the annual gathering of the Northern California Chapter of the American Public Works Association. The talk was titled, “Keeping you Communities Cool: Tools for Reducing Urban Heat”. It started with an introduction to the growing problem of urban heat and the scientific fundamentals behind cool materials. Because the audience was composed primarily of representatives from municipal agencies, many of them focused on stormwater management and transportation, I focused largely on cool pavements, and only touched briefly on cool roofs and shade trees. The bulk of the presentation focused on the benefits that can be derived from large scale introduction of cool pavements and the range of pavement options that are available.

The audience was remarkably engaged and we were able to have a good discussion about the trade-offs between some of the different pavement options, the state of the science, and some of the challenges of advancing the use of cool pavements and shade trees when working in municipal public works departments. One example is that the public tends to like having black paved surfaces because it makes them feel as though their roads and parking lots are new and in good repair!

My presentation is available on the Knowledge Base: