We present the development and application of the novel in situ cosmogenic 14C/10Be chronometer to recently exposed proglacial bedrock of the Rhone Glacier, Switzerland. Results show that during the Holocene, the glacier was smaller than today for 6500 ± 2000 yr and larger than today for 4500 ± 2000 yr. This pattern is consistent with limited data from other techniques for glaciers in the Alps and Scandinavia, but in contrast to glaciers from the Southern Alps of New Zealand, emphasizing the high sensitivity of large mountain glaciers to small climate changes. The 14C/10Be chronometer also shows that abrasion rates beneath the Rhone Glacier increased with ice speed.

Middle Stone Age humans in high-altitude Africa: Recent archaeological research has produced evidence of the earliest human occupation of high-altitude habitats in the Andes and the Tibetan Plateau. Ossendorf et al. now present the oldest evidence of human settlement and adaptation to areas above 4000-meter elevation in Africa (see the Perspective by Aldenderfer). Their excavations at a rock shelter in the Bale Mountains of Ethiopia reveal obsidian artifacts and faunal remains, including abundant burnt bones, mostly of giant mole-rats. The findings reveal the environmental conditions and show how Late Pleistocene humans adapted to the harsh environments of these glaciated high-altitude African landscapes. Science , this issue p. 583 ; see also p. 541

The natural variability of Holocene climate defines the baseline to assess ongoing climate change. Greenland ice-core records indicate warming superimposed by abrupt climate oscillations in the early Holocene, followed by a general cooling trend throughout the middle and late Holocene that culminated during the Little Ice Age (LIA). Tropical precipitation changes correlate with these patterns throughout the Holocene. Here we use mountain glaciers in the European Alps to reconstruct the regional Holocene climate evolution and to test for a link between mid-latitude, North Atlantic, and tropical climate. Our precise ¹⁰Be chronology from Tsidjiore Nouve Glacier, western Swiss Alps, indicates a glacier culmination during the earliest Holocene ∼11.4 k.y. ago, likely related to the Preboreal Oscillation. Based on our data, no Holocene glacier advance of similar amplitude occurred until ∼3.8 k.y. ago, when the glacier reached LIA limits. The ¹⁰Be ages between 500 and 170 yr correspond to the LIA, while the youngest ¹⁰Be ages overlap with the historically recorded post-LIA glacier positions. Integrating our data with existing records, we propose a hemispheric climate link between the Alps, North Atlantic temperature, and tropical precipitation patterns for the Holocene, supporting the concept of a pervasive climate driver. These findings from northern mid-latitudes are consistent with the hypothesis formulated for the tropics that the Earth’s thermal equator, responding to North Atlantic temperature changes, might have migrated southward throughout the Holocene, reaching the southern turning point toward the end of the LIA.