English: Graph showing Atmospheric CH4 parts per billion : CO2 parts per million : temperature °C variation from present temperatures, from 420,000 year Before Present to Present time. The correlation between CH4 methane concentrations and average earth temperatures is closer than with CO2 carbon dioxide. As can be seen, current levels of CO2 @400ppm correlate with +4°C, well above the +2°C limits proposed by IPCC. But current levels of CH4 methane @1830ppb (2015) correlate with more than +12°C earth temperature increase. Based on Antarctic and Greenland ice-core data and atmospheric data from Cape Grim station, Tasmania. Vostok ice core data: Petit et al, Nature (No. 399, 1999). Low Dome ice core data: Etheridge, et al, (Journal of Geophysical Research 1996). Cape Grim Station data: CSIRO Atmospheic Research and Bureau of Meteorology. °C between 160,000 and 420,000 years BP from IPCC. Graph by Reg Morrison regmorrison.edublogs.org/articles. This material is licensed under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Int’l