ESS101C
Prof.
Jin-Yi Yu
Orbital-Scale Changes in CO2
qThe longest orbital-scale record
of CO2 changes
comes from the Vostok ice core drilling site.
qThe CO2 record shows a series of
regular oscillation
between CO2 values as high as 280-300 ppm and as low as 180-190 ppm over the last 400,000
years.
qValues at the high end of this range occur within the present interglacial
interval.
qThese relative high CO2 values lasted for several thousand years before
the abrupt increase
after 1800.
qThe dominant period of CO2
variations is about 100,000 years.
(from Earth’s Climate: Past and Future)