It's concrete - China now top CO² emitter

China has officially become the world's largest CO² emitter, months ahead of the most dire warnings.Estimates on when China would overtake the US on greenhouse gas emissions had varied, but Dr Fatih Birol, chief economist of the Paris-based International Energy Agency, said in April it could happen within months.The country's economic growth had been so fast in 2006 and 2007 that the historic