Table 1.

Rates of change in atmospheric CO2 concentration ([CO2]atm, ppm/100 years) and global temperature (°C/100 years) calculated for the past 420,000 yr B.P. using the Vostok Ice Core data (5) and compared to changes over the last century and those projected by IPCC for low-emission (B1) and high-emission (A2) scenarios (8). Rates were calculated for each successive pair of points in the Vostok Ice Core record by dividing the difference between two sequential values (ppm or °C) by the time interval between them. Rates were then standardized to the change seen over 100 years. Ratios of each rate relative to the mean rate seen over the past 420,000 years are also calculated.

Period[CO2]atm (ppm century-1)Ratio (relative to past 420,000 years)Temperature (°C century-1)Ratio (relative to past 420,000 years)
Past 420,000 years (99% confidence interval; n = 282) 0.07 + 0.223 1 0.01 + 0.017 1
Past 136 years (1870-2006) 73.53 1050 0.7 70
IPCC B1 scenario: 550 ppm at 2100 170 2429 1.8 180
IPCC A2 scenario: 800 ppm at 2100 420 6000 3.4 420