China has already overtaken the US to become the world's top emitter of carbon dioxide, according to a report released Tuesday by the Netherlands Environmental Assessment Agency. It claims that in 2006, China's emissions were 8% higher than those of the US, having trailed America by 2% in 2005. Earlier projections made by the UN and US Energy Information Administration said China would overtake the US in 2009 or 2010, AP reported. "It's an expression of their fast industrial production activities and their fast development," said Jos G.J. Olivier, the agency's senior scientist who compiled the figures. The rise has been put down to the country's voracious burning of coal as well as its massive cement consumption. The study said China relies on coal for two-thirds of its energy needs and makes 44% of the world's cement. All told, the country produced 6.2 billion metric tons of carbon dioxide in 2006, while the US – which only gets half its electricity from coal-powered sources – generated 5.8 billion metric tons.