That's equal to 20 percent of all the carbon released from burning fossil fuels in the past 200 years. (discovermagazine.com)
The excess CO2 we put into the atmosphere by burning fossil fuels such as coal, oil, or natural gas is removed very slowly by ocean uptake and other geological processes. (slate.com)
The remaining 39 billion tons of annual human - made CO2 emissions come from other activities like burning fossil fuels in power plants and vehicles and producing concrete. (ibtimes.com)