Tag Archives: China

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 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.