https://meetingorganizer.copernicus.org/EGU2013/EGU2013-9808-1.pdf

Southern Hemisphere westerly wind changes during the Last Glacial Maximum: paleo-data synthesis

13 Abstract 14 Changes in the strength and position of Southern Hemisphere westerly winds during the 15 last glacial cycle have been invoked to explain both millennial and glacial-interglacial climate 16 fluctuations. However, neither paleo models nor paleo data agree on the magnitude, or even the 17 sign, of the change in wind strength and latitude during the most studied glacial period, the Last 18 Glacial Maximum (LGM), compared to the recent past. This paper synthesizes paleo- 19 environmental data that have been used to infer changes in LGM winds. Data compilations are 20 provided for changes in terrestrial moisture, dust deposition, sea surface temperatures and ocean 21 fronts, and ocean productivity, and existing data on Southern Hemisphere ocean circulation 22 changes during the LGM are summarized. We find that any hypothesis of LGM wind and 23 climate change needs to provide a plausible explanation for increased moisture on the west coast 24 of continents, cooler temperatures and higher productivity in the Subantarctic Zone, and 25 reductions in Agulhas leakage around southern Africa. Our comparison suggests that an overall 26 strengthening, an equatorward displacement, or no change at all in winds could all be interpreted 27 as consistent with observations. If a single cause related to the southern westerlies is sought for 28 all the evidence presented, then an equatorward displacement or strengthening of the winds 29 would be consistent with the largest proportion of the observations. However, other processes, 30 such as weakening or poleward shifts in winds, a weakened hydrological cycle, extended sea-ice 31 cover, and changed buoyancy fluxes, cannot be ruled out as potential explanations of observed 32 changes in moisture, surface temperature, and productivity. We contend that resolving the 33 position and strength of westerly winds during the LGM remains elusive based on data 34 reconstructions alone. However, we believe that these data reconstructions of environmental 35 conditions can be used in conjunction with model simulations to identify which processes best 36 represent westerly wind conditions during the LGM. 37 38

Southern Hemisphere Westerly Wind Changes during the Last Glacial

Study of human adaptation to extreme environments is important for understanding our cultural and genetic capacity for survival. The Pucuncho Basin in the southern Peruvian Andes contains the highest-altitude Pleistocene archaeological sites yet identified in the world, about 900 meters above confidently dated contemporary sites. The Pucuncho workshop site [4355 meters above sea level (masl)] includes two fishtail projectile points, which date to about 12.8 to 11.5 thousand years ago (ka). Cuncaicha rock shelter (4480 masl) has a robust, well-preserved, and well-dated occupation sequence spanning the past 12.4 thousand years (ky), with 21 dates older than 11.5 ka. Our results demonstrate that despite cold temperatures and low-oxygen conditions, hunter-gatherers colonized extreme high-altitude Andean environments in the Terminal Pleistocene, within about 2 ky of the initial entry of humans to South America.

https://science.sciencemag.org/content/sci/346/6208/466.full.pdf

Paleoindian settlement of the high-altitude Peruvian Andes

Nature and causes of Quaternary climate variation of tropical South America

A 130 ka reconstruction of rainfall on the Bolivian Altiplano

Lake highstands on the Altiplano (Tropical Andes) contemporaneous with Heinrich 1 and the Younger Dryas: new insights from ^(14)C, U-Th dating and δ^(18)O of carbonates

J.L. Seidel

Papers

Lake highstands on the Altiplano (Tropical Andes) contemporaneous with Heinrich 1 and the Younger Dryas: new insights from ^(14)C, U-Th dating and δ^(18)O of carbonates