New Antarctic ice core offers tantalising climate clues 10 June 04

The oldest ever ice core – containing a unique climate record extending 740,000 years back in time – has been extracted from Dome C in Antarctica, and preliminary results published in Nature (see free-to-view news article). Previously the oldest core came from the Vostok research station, which showed that the Earth has experienced a 100,000-year ice age cycle for 420,000 years. It also showed that greenhouse gas concentrations marched in lock-step with temperature (see famous IPCC graph), proving conclusively that carbon dioxide and methane regulate the Earth’s temperature. Worryingly, greenhouse gas concentrations are far higher now than during the entire Vostok record. The Dome C CO2 and methane levels have yet to be revealed, but they too are likely to be far lower than present concentrations. What has been revealed is that under natural conditions the current interglacial (warm period) would be likely to last another 15,000 years – so those who suggest that fossil fuel emissions could save us from another ice age are sorely mistaken.