Ice core record extended: Analyses of trapped air show current CO2 at highest level in 650,000 years
Chemical & Engineering News. 83.48 (Nov. 28, 2005): p7.
Abstract: 

Data from a new ice core called EPICA Dome C reveals the relationship between global temperatures and atmospheric carbon dioxide concentrations for the period 390,000 to 650,000 years before present. The data indicated that the current concentration of CO2 at 380 ppm is twenty-seven percent higher than the preindustrial level and higher than any level attained during the past 650,000 years.

Source Citation   (MLA 8th Edition)
Hileman, Bette. "Ice core record extended: Analyses of trapped air show current CO2 at highest level in 650,000 years." Chemical & Engineering News, 28 Nov. 2005, p. 7. General Science Collection, go.galegroup.com%2Fps%2Fi.do%3Fp%3DPPGS%26sw%3Dw%26u%3Dvol_f162hs%26v%3D2.1%26id%3DGALE%257CA140135097%26it%3Dr%26asid%3D17927a731a882ac5fd5c3a22fe59aea9. Accessed 19 Nov. 2017.

Gale Document Number: GALE|A140135097