Global carbon dioxide emissions 2010-2021, by select country

China and the United States are the largest polluters in the world by far, having released 11.5 and 5.0 billion metric tons of carbon dioxide emissions in 2021, respectively. Despite being the second-largest polluter, U.S. emissions have declined by 12 percent since 2010. In comparison, China’s carbon dioxide emissions have increased by over 33 percent.

Cumulative emissions

Although China is currently the world's largest carbon polluter, it has released roughly half the cumulative carbon dioxide emissions the U.S. has since 1750, which is more than 400 billion metric tons. The wide gap between the two countries is mainly because China's emissions have mostly been produced in the past two decades. Since 2000, per capita CO₂ emissions in China have roughly tripled. In comparison, per capita emissions in the west have noticeably dropped.

Impact of COVID-19 on emissions

Although global carbon dioxide emissions have risen to record highs, the outbreak of COVID-19 had a dramatic impact on emissions in 2020, resulting in the largest annual drop in CO₂ emissions ever. This was due to energy demand falling because of strict lockdowns and transportation bans.