Global Cooling: Effect of Urban Albedo on Global Temperature

Conference · Tue May 22 04:00:00 EDT 2007

OSTI ID:932530

Akbari, Hashem; Menon, Surabi; Rosenfeld, Arthur

In many urban areas, pavements and roofs constitute over 60% of urban surfaces (roof 20-25%, pavements about 40%). The roof and the pavement albedo can be increased by about 0.25 and 0.10, respectively, resulting in a net albedo increase for urban areas of about 0.1. Many studies have demonstrated building cooling-energy savings in excess of 20% upon raising roof reflectivity from an existing 10-20% to about 60%. We estimate U.S. potential savings in excess of $1 billion (B) per year in net annual energy bills. Increasing albedo of urban surfaces can reduce the summertime urban temperature and improve the urban air quality. Increasing the urban albedo has the added benefit of reflecting more of the incoming global solar radiation and countering the effect of global warming. We estimate that increasing albedo of urban areas by 0.1 results in an increase of 3 x 10{sup -4} in Earth albedo. Using a simple global model, the change in air temperature in lowest 1.8 km of the atmosphere is estimated at 0.01K. Modelers predict a warming of about 3K in the next 60 years (0.05K/year). Change of 0.1 in urban albedo will result in 0.01K global cooling, a delay of {approx}0.2 years in global warming. This 0.2 years delay in global warming is equivalent to 10 Gt reduction in CO2 emissions.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE. Assistant Secretary of Energy Efficiency andRenewable Energy; California Energy Commission through its PublicInterest Energy Research Program
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 932530
• Report Number(s): LBNL--63490; BnR: YN0100000
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
AIR QUALITY
ALBEDO
AMBIENT TEMPERATURE
GREENHOUSE EFFECT
PAVEMENTS
REFLECTIVITY
ROOFS
SOLAR RADIATION
URBAN AREAS
VENTILATION