A paleoclimatic perspective on the 21st-century glacier loss on Kilimanjaro, Tanzania

作者：Thompson Lonnie G^*; Mosley Thompson Ellen; Davis Mary E; Mountain Keith

来源：Annals of Glaciology, 2011, 52(59): 60-68.

Assessing the significance of current glacier loss on Kilimanjaro, Tanzania, demands a well-constrained temporal perspective. That context is provided by direct measurements, ancillary observations of the ice fields and the analyses of the ice cores collected from them. Ice retreat mechanisms observed there today are consistent with the preservation of the oldest ice, similar to 11.7 ka, in the central deepest part of the Northern Ice Field (NIF). This ice-core derived paleoclimate history published by Thompson and others (2002) is further confirmed by more recent paleoclimate records from tropical East Africa. Mounting evidence suggests that the (anticipated) loss of the entire NIF will be unprecedented within the past 10 000 years. New evidence bears directly on the mechanisms driving the current ice loss. Measurements made in 2000 on the NIF document that air temperature at 0.5 and 1.5 m above the surface remained below -5 degrees C, while a surface temperature of 0.0 degrees C was sustained for up to 8 hours d(-1) under clear conditions, consistent with observations of melting on all Kilimanjaro summit ice fields. The linear relationship between oxygen and hydrogen isotopic ratios for all six ice cores drilled in 2000 lies very close to the global meteoric waterline and does not support sublimation (evaporation) as a major driver of ice loss today or in the past on Kilimanjaro.

• 出版日期2011