Increases are relative to 1980–1999 for different emission scenarios (IPCC 2007). The partial pressure of carbon dioxide in the atmosphere (pCO2) is assumed to attain a value of 800 to 1 000 parts per million (ppm) at the end of this century for scenario A2. It increases to about 700 ppm in scenario A1B and reaches approximately 500 ppm in scenario B1. The current pCO2 value of about 390 ppm is maintained until the end of the century in the constant composition scenario.
From collection: Frozen Heat - A Global Outlook on Methane Gas Hydrates