Category Archives: Uncategorized

Urban Heat Island Turns Top Floor Apartments into Ovens

It doesn’t matter where you live – extreme urban heat is a major problem and it’s getting worse.   As the effects of climate change take hold, temperatures are steadily rising – this year is on track to be the hottest on record and there’s no relief in sight for city-dwellers.   Especially those in poorer neighborhoods.

This article from the South China Morning Post about a recent study paints a grim picture for people living in older buildings.   Their homes get hotter and they spend a higher percentage of their income struggling to keep cool.

Low-income dwellers living on the top floors of old tenement buildings have become the forgotten victims of the urban heat island effect, a green group has found.

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The heat – trapped in bare, unpainted concrete – dissipates into households below turning flats into “ovens”.

“The rooftops of some of these old buildings can get so hot you can fry eggs on them,” said Dr William Yu Yuen-ping, chief executive at the World Green Organisation, the group that carried out the study.

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One measurement at Mong Kok one afternoon measured a maximum rooftop temperature of 74.4 degrees.   The air temperature in the flat below rose to 36.8 degrees, five degrees higher than the 32 degree mean temperature recorded by the Observatory that day.

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Yu urged the government and the Commission on Poverty’s Community Care Fund to help these households by offering subsidies for planting rooftop gardens or painting buildings in white to dissipate heat.

Rooftop temperatures of 74.4 degrees Celsius – that’s 165.2 degrees Fahrenheit by the way.  And inside the top floor apartments… over 98 degrees Fahrenheit.   This problem is universal and white roofs can help lower the temperature, reduce energy consumption and save lives.

Cool Roofs Perform Well in Cool Climates

Stan Graveline of Sika Sarnafil wrote a great piece defending the use of cool roofs in cooler areas of the country. He does a great job laying out the science, as well as the fact that billions of square feet of cool roofs are installed in northern areas and performing well. Check it out at Professional Roofing magazine.

Los Angeles White Roofs Building Code is Online

Speaking of useful resources…

Last December, the Los Angeles City Council updated the city’s building code – which required the installation of white roofs on commercial structures – to require the installation of white roofs on new and rebuilt residential structures.  The city has put all the documents and discussion on line in their docket – including the City Attorney’s report.

Since then, several other cities (Pasadena and Hermosa Beach, CA) have enacted similar updates.  We thought it might be useful for other cities to have access to the relevant documents and reports, so we’ve added information on Los Angeles to our ToolKit Knowledge Base, which you can find HERE.

Cool Resources for Cool Cities

This is just a quick reminder that we’ve put together a great resources page here on our ToolKit, and we hope you’ll explore it a little to see what else is available on reflective surfaces.  Meanwhile, here are a few of the highlights…

Our guide on cool roofs and pavements is a must-read for anyone interested in bringing down urban heat in their city.  We also have a handy implementation guide to help city administrators put these great ideas into practice.

A Practical Guide to Cool Roofs and Cool Pavements

Cool Roofs and Cool Pavements Toolkit – An Implementation Guide for Cities

The Cool Roofs Ratings Council has put together a comprehensive database of city codes, rebates and incentive programs..

Cool Roofs Ratings Council – Codes, Rebates and Incentive Programs

You can also use this handy cool roofs ratings calculator from the US Department of Energy, in calculating heating and cooling efficiencies.

DOE Cool Roof Calculator

The Heat Island Group at the Lawrence Berkeley National Laboratory has put together a handy interactive map that helps determine the solar reflectance of individual roofs in the California cities of Bakersfield, Long Beach, Los Angeles, San Francisco, and San Jose.

LBNL Interactive Solar Reflectance Maps

Study Shows How Increased Reflectivity Can Save Lives

Researchers at the Georgia Institute of Technology recently published a report, in which they took a look at past heat waves in Phoenix, AZ, Philadelphia, PA and Atlanta, GA.

This study shows that by adding white roofs, reflective pavement and trees, cities can counteract temperature increases in urban areas and save lives. From an article byClimateWire …

[T]he researchers modeled how the three cities would respond to a minimum green space ratio on land parcels, setting a floor for areas covered with grass, gardens or trees. Vegetation tends to have a cooling effect by circulating moisture in the air that draws away heat during evaporation. Tree canopies also provide cooling shade.

The team also modeled how Phoenix, Philadelphia and Atlanta would behave with more reflective streets, sidewalks, parking lots and rooftops. Higher reflectivity, or albedo, means the area absorbs less sunlight, thereby lowering the temperature.

Stone and his collaborators then overlaid a health impact model.  They found that combinations of increased vegetation and albedo could cut into projected increases in heat deaths, reducing them between 40 and 99 percent. “On average, we reduced the rate of increase by about 60 percent,” Stone said.

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Groups like the Global Cool Cities Alliance are now trying to get cities to adopt these adaptation strategies, pitching them as a way to protect public health. However, it’s slow going, given that cities around the country address heat vulnerability differently, if at all.

You can find the full study HERE.

This report parallels a recent GCCA report, which looks at Baltimore MD, New York, NY, and Los Angeles, CA, and shows how reflective roofs and vegetation can cool air temperatures and save lives.

Note: Access to the ClimateWire articles is limited to subscribers.

Catch GCCA Executive Director Kurt Shickman on KCRW

Madeleine Brand, a reporter for NPR station KCRW in Santa Monica, California, noted that extreme heat is now the most deadly of weather-driven disasters.  She invited GCCA’s Executive Director, Kurt Shickman on her show to talk about the urban heat island effect, and Kurt explained how cool roofs can help cities cool down, conserve energy and save lives.  Kurt noted the many affordable color options available in today’s roofing marketplace.

They also discussed the new regulations in Los Angeles, which require white roofs on new commercial and residential buildings, as well as major roof rebuilds.

You can listen to the show here, and read more about efforts to bring down temperatures in Los Angeles with cool roofs,here.

LBNL Develops New Interactive Rooftop Reflectance Map

Scientists at the Lawrence Berkeley National Laboratory (LBNL) have created an interactive map that displays the solar reflectance (or albedo) of individual roofs in five major California cities – Bakersfield, Long Beach, Los Angeles, San Francisco, and San Jose.   This is the first time scientists have attempted to map the reflectivity of entire cities.

A white / high-albedo cool roof reflects 80% of the sun’s heat, decreasing solar heating of the building. This reduces the need for air conditioning and lowers energy bills. Cool roofs could also partially counter increased urban temperatures brought on by climate change.

This map allows users to zoom in on a specific rooftop to see how it compares to the albedo of a white roof, or other roofs in the city, and is designed to help cities develop policies that could lead to cooler cities.

Ronnen Levinson, head of LBNL’s Heat Island Group and Board Member of the Global Cool Cities Alliance says this new map can be a useful tool for cities:

To assess these potential benefits for a particular city, we need to measure the reflectance of its roofs with good spatial and spectral resolution.  Our map helps bring this into focus.

You can explore LBNL’s new interactive map HERE.

Cool Roofs and Energy Efficiency in China

The Lawrence Berkeley National Laboratory (LBNL) has conducted the first comprehensive study of cool roofs in China and concluded that they would be an effective way to reduce energy use and greenhouse gas emissions.

Researchers ran simulations on residential and commercial buildings in seven cities in five climate zones, and found that light colored roofs reduced the need for air conditioning and energy consumption, and lowered the output of greenhouse gas trapping carbon dioxide.

LBNL scientist and lead author, Ronnen Levinson (member of GCCA’s Board) had this to say:

“Cool roofs have been well demonstrated in the United States, Europe, and elsewhere,” said lead author and Berkeley Lab scientist Ronnen Levinson. “While the concept is the same everywhere, we wanted to show that cool roofs would also be effective for Chinese construction, in Chinese climates, and with Chinese building operation practices.”

You can find the full study in the Toolkit’s Knowledge Base.

New Cool Roofs Project Takes Off in Seoul, South Korea

Seoul, South Korea launches a new cool roofs initiative with a campaign to help people paint their roofs white, and plans to expand the program next year:

The Seoul city government will soon come up with plans to expand the initiative in stages.  For example, it will begin with pilot projects in a select number of buildings from this year, followed by a bigger program in 2015 that will include financing support to those building owners that implement building retrofit projects.

(This article also gives brief mention to research conducted by GCCA Board Member, Hashem Akbari.)