“Recent warming”: ice core evidence from tropical ice cores with emphasis on Central Asia

Abstract

Ice cores from the tropics and subtropics, in conjunction with those from the polar regions, provide a multifaceted record (dust, chemistry, stable isotopes, accumulation) of environmental changes which can be viewed both spatially and temporally. This paper emphasizes the oxygen isotopic record ( δ 18O) preserved in cores from the poles to the tropics and assesses the evidence for global warming in the last 50–100 years. From north to south these records include: Camp Century, Greenland, Dunde and Guliya Ice Caps, China, Gregoriev Ice Cap, Kirghizia (formerly part of USSR), Quelccaya Ice Cap, Peru and Siple Station and South Pole, Antarctica. The central Asian records along with that from Quelccaya provide strong evidence of recent and rapid warming in the tropics and subtropics. For the Dunde Ice Cap, where a long paleoclimatic record is available, the warming in this century appears to be unprecedented in the Holocene. These tropical and subtropical records contrast sharply with those from polar cores which show little evidence of a recent warming. These data suggest that either the recent warming is a middle and lower latitude phenomenon or that these high altitude tropical and subtropical glaciers may be more sensitive to climate changes than the massive polar ice sheets. Regardless, the current rapid disintegration of many tropical and subtropical glaciers may result in the permanent loss of numerous unique archives.