Ice Cores Reveal CO2 Highest for 800,000 Years
Scientists at the British Antarctic Survey in Cambridge carrying out a study on the oldest Antarctic ice core [search] have found that the rapid rise in greenhouse gases over the past century is unprecedented in at least 800,000 years [more | more2]. During the period 8 cycles of high carbon dioxide and methane coincided closely with relatively high temperatures associated with warm, inter-glacial periods. It is noted the “rate of change is probably the most scary thing”.
“The core shows that carbon dioxide was always between 180 parts per million (ppm) and 300 ppm during the 800,000 years. However, now it is 380 ppm. Methane was never higher than 750 parts per billion (ppb) in this timescale, but now it stands at 1,780 ppb… increases in carbon dioxide never exceeding 30 ppm in 1,000 years — and yet now carbon dioxide has risen by 30 ppm in the last 17 years.”