Canwest News Service: Gas-guzzling vehicles are one of the key factors behind the notorious environmental record of Canadians who are among the highest per capita polluters in the world, according to figures released Tuesday by Statistics Canada. Each Canadian produces an average of 23 tonnes of carbon dioxide equivalent emissions per year, trailing Americans, who create an average of 24.4 tonnes of emissions per year, and Australians, with an average of 27.7 tonnes of emissions per year, according to the …