In 1900, almost 2 billion metric tons of CO2 were released due to fossil fuel usage. By 1960, that number had more than quadrupled to over 9 billion metric tons.
The latest data from the Carbon Dioxide Information Analysis Center shows that over 35 billion metric tons of CO2 were released in 2014. *
Because emissions are only partially reduced by natural land and ocean sinks, the rest of the annual carbon dioxide emissions from the human burning of fossil fuels remains in Earth's atmosphere, resulting in the annual year-over-year rise in atmospheric concentrations of carbon dioxide, as seen here.
Explore NASA's climate vital signs to learn more about carbon dioxide and other factors related to climate change.