The study looked at whether population, international trade, and energy consumption are the main factors causing environmental damage in China from 1971 to 2011. They found that in the long run, energy use and population growth increase CO2 emissions, while in the short run, energy use and trade decrease CO2 emissions. The analysis also showed that CO2 emissions lead to more energy consumption, and energy consumption and population lead to more trade. The researchers suggest policy changes based on these results.