ESS101C
Prof.
Jin-Yi Yu
Ice Sheet and CO2
qWe have learned that the
dominant cycle of ice sheet variations over the last several hundred years has also been
100,000 years.
qThis suggests that the
100,000-year variations in atmospheric CO2 match those of ice sheets.
qOver the
400,000-year length of the ice core record, the major cycles of CO2 change line up well with the ice
volume changes
(indicated by d18O).
qThe two
signals share not only the 100,000-year cycle but also its asymmetric shape: abrupt increases in CO2 during
times of rapid ice
melting (i.e., warming) and slower decreases during times of slower phases of ice volume buildup
(cooling).
qWHY?
(from Earth’s Climate: Past and Future)
(from Earth’s Climate: Past and Future)