The latter is almost linearly related to changes
in ice sheet volume; the former, however, is influenced by a range of factors, including atmosphere / ocean dynamics and changes in Earth's gravitational field, rotation, and crustal and the mantle deformation associated with the redistribution of mass between land ice and the ocean.
Independently, Greenland and
Antarctic ice sheet volumes were estimated by observations from adjacent ocean sediment records and by ice sheet models.
Shackleton (2000); changes of CO2 preceding changes
in ice sheet volume were reported in Shackleton and Pisias (1985).
Evolution of Greenland surface elevation and
ice sheet volume versus time in the experiment of Ridley et al. (2005) with the UKMO - HadCM3 AOGCM coupled to the Greenland Ice Sheet model of Huybrechts and De Wolde (1999) under a climate of constant quadrupled pre-industrial atmospheric CO2.