The Milankovitch theory of climate change proposes that glacial–interglacial
cycles are driven by changes in summer insolation at high northern latitudes1.
The timing of climate change in the Southern Hemisphere at glacial–
interglacial transitions (which are known as terminations) relative to
variations in summer insolation in the Northern Hemisphere is an important
test of this hypothesis. So far, it has only been possible to apply this test
to the most recent termination2, 3, because the dating uncertainty associated
with older terminations is too large to allow phase relationships to be
determined. Here we present a new chronology of Antarctic climate change over
the past 360,000 years that is based on the ratio of oxygen to nitrogen
molecules in air trapped in the Dome Fuji and Vostok ice cores4, 5. This ratio
is a proxy for local summer insolation5, and thus allows the chronology to be
constructed by orbital tuning without the need to assume a lag between a
climate record and an orbital parameter. The accuracy of the chronology allows
us to examine the phase relationships between climate records from the ice
cores6, 7, 8, 9 and changes in insolation. Our results indicate that
orbital-scale Antarctic climate change lags Northern Hemisphere insolation by
a few millennia, and that the increases in Antarctic temperature and
atmospheric carbon dioxide concentration during the last four terminations
occurred within the rising phase of Northern Hemisphere summer insolation.
These results support the Milankovitch theory that Northern Hemisphere summer
insolation triggered the last four deglaciations3, 10, 11.
http://www.nature.com/nature/journal/v448/n7156/abs/nature06015.html#a9
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