|These images provide a comparison between the water-ice accumulation rates in the
present day and 21,500 years ago. Present-day map shows a net accumulation of
water-ice only at the South Pole itself, where the existence of a CO2 cold-trap
forces a local and permanent deposition of water-ice. In the inversed situation
(21,500 years ago), the CO2 cold trap has been removed and the pattern of
accumulation is only controlled by the precipitation/sublimation of water vapor on
an annual average.
Credit: OMEGA team - F.Montmessin - Service d'AÃ©ronomie du CNRS - IPSL