Almost half of Britons do not believe human behaviour is the main cause of global warming, a new poll showed Sunday, a day before world leaders begin crunch climate talks in Copenhagen。

　　The ICM survey for The Sunday Telegraph newspaper found 52 percent of respondents thought humans were largely responsible for modern dayrises in temperatures, but 39 percent said climate change had not yet been proven to be man-made。

　　A further seven percent did not believe climate change was happening at all。

　　Meanwhile,23 percent thought climate change was "the most serious problem faced by man", with 58 percent saying it was merely "one of a number of serious problems", while 17 percent said it was "not a very serious problem"。

　　
　　The findings are likely to concern world leaders such as Prime MinisterGordon Brown who believe an international deal in Copenhagen on cutting greenhouse gas emissions is the best way to combat climate change。

　　
　　They follow a rowover leaked emails from a key climate research unit at the University of East Anglia, which sparked claims that scientists were trying to suppress data which did not support the view that climate change is happening。

　　
　　Some US lawmakers and a top Saudi official have said the emails undermine the science of climate change。

　　
　　However,Brown this weekend said people who denied man's impact on global warming were "behind-the-times, anti-science, flat-earth climatesceptics"。

　　
　　ICM questioned 1,001 adults by telephone on December 2-3.