Figure 1

The figure shows a reconstruction of the temperature of the last 50,000 years based on measurements of oxygen isotope 18 in the ice. The stable interglacial period of the last 10,000 years is the Holocene; the unstable cold period preceding it is the second half of the last great ice age. Dansgaard-Oeschger events (refer to the text for an explanation) are marked in red and numbered. The vertical lines are spaced at intervals of 1,470 years; the majority of DO events are located near such lines.