[BEIJING] Rising wintertime temperatures in China mean that people do not need to use as much energy to heat their homes as compared with previous years, according to a Chinese study.
The study was published in the latest issue of the Chinese Science Bulletin (May 30).
Lead author Chen Li of the Harbin Meteorological Bureau in Heilongjiang province, and colleagues from Beijing Normal University and the Meteorological Bureau of Heilongjiang Province analysed average winter temperatures in northern Chinese cities from the past 50 years.
Their results agreed with previous studies showing a warming trend of winters in northern Chinese cities since the mid-1980s. Chen and colleagues also found that regions of cold and severe cold in northern China had shrunk and that their southern boundaries had shifted in latitude as much as two degrees north.
Based on annual temperatures, the authors calculated the energy needed to keep a room at a standard fixed temperature — 18 degrees Celsius — before and after the mid-1980s.
The researchers found that after the mid-1980s, the energy needed to reach and maintain the standard temperature was about 5–10 per cent lower than before the mid-1980s.
Chen says because of the unavailability of actual coal consumption figures for winter heating — and the variation of coal quality used in different regions — the reduced energy consumption for heating since the mid-1980s is more of a theoretical calculation than a real figure.
"In practice, many Chinese cities have not reduced their coal consumption because they are not aware that less energy is needed to reach the required heating standard amidst climate change," Chen told SciDev.Net. "In this sense, the study's results are important to spread among urban heating operators."
Previous work has shown that heating buildings makes up about 15 per cent of human-induced carbon dioxide emissions in China, so the authors say that excessive heating in the past is likely to have contributed to the rise in wintertime temperatures through climate change.
The authors say the study indicates that taking measures to adapt to climate change could help to lessen its further development.
Chen added that a follow-up study — which has not yet been published — found that although warmer temperatures will mean more air conditioning is required in summer, this will not completely cancel out the energy saving from heating, as air conditioning does not use as much energy.
Reference: Chinese Science Bulletin, 52, 1195 (2007)