With an estimated population of 1,439,323,776 people, China has become one of the world's leading contributor to greenhouse gas emissions due to its ongoing rapid urbanization.  Even with the growing increase in building infrastructure, China has long been considered as a country where the overall energy demand has consistently grown less rapidly than the gross domestic product (GDP) of China.  Since the late 1970s, China has been using half as much energy as it did in 1997, but due to its dense population and rapid growth of infrastructure, China has become the world's second largest energy consumer and is in a position to become the leading contributor to greenhouse gas emissions in the next century.