Figure 13
Oxygen isotope curve for the last 40,000 years from
the GISP-2 ice core in central Greenland. This is a proxy for average annual air temperatures
over Greenland, as indicated on the right side of the graph. The timeline reads
from right to left. Note that the temperature swings before 10,000 years ago
were orders of magnitude greater. Before the current interglacial, average
annual temperatures
in the North Atlantic region were gyrating by as much as 30°F, and these changes were happening in no more
than a decade (the sample resolution of the record). The heavy black bars
delimit the Bolling-Allerod global climatic warming of ca. 15,500 years
ago. Compare to the dates from Brokenleg Bend #1 and Sergeant Major Creek #1 in
Figures 11 and 12. From Maher and Mickelson 1996: Figure 8.