录音中在介绍美国是二氧化碳最大排放国时，提到“The U.S., with five percent of the world’s population...”，可知美国人口占据世界人口的5%。
【录音原文】
　　In a recent 12-month span, carbon emissions from the burning of fossil fuels climbed to more than 7, 900, 000, 000 tons, a record high. Global emissions of carbon have been rising steadily since the late 18th century and rapidly since the 1950s. In fact, annual emissions have quadrupled since the mid-20th century.
　　Three-fourths of global carbon emissions are the result of burning fossil fuels, namely coal, oil, and natural gas. The rest largely come from deforestation. Of the four major sectors contributing to these emissions, electricity generation—at 35％—accounts for the largest share; transportation and industrial processes, 20％each. The remaining 25％is produced by residential and commercial buildings. Two-thirds of the carbon emissions from fossil fuel combustion are emitted by just 10 nations. The U.S., with five percent of the world’s population, is the largest contributor, accounting for nearly one-quarter of global emissions. China is second, with nearly l4％. Other major polluters are Russia, Japan, India, Italy, Canada, South Korea, Germany, and the United Kingdom.
　　Most of the growth in emissions in the coming decades, however, is expected to come from developing countries. While overall global carbon emissions have risen 13％since 1990, those in China have jumped 47％. Indeed, this one country accounts for nearly half of the global increase in emissions in the last decade.