@article {2913,
	title = {Insolation and greenhouse gases drove Holocene winter and spring warming in Arctic Alaska},
	journal = {Quaternary Science Reviews},
	volume = {242},
	year = {2020},
	month = {Jan-08-2020},
	pages = {106438},
	abstract = {Global surface temperature changes and their drivers during the Holocene Epoch remain controversial. Syntheses of proxy data indicate that global mean annual temperature declined from the mid-Holocene until the Pre-industrial Era, a trend linked to decreasing Northern Hemisphere summer insolation. In contrast, global climate models simulate increasing mean annual temperatures driven by retreating ice sheets and increasing greenhouse gas concentrations. This proxy-model disagreement may originate from a warm season bias in Northern Hemisphere proxy reconstructions, highlighting the need for new proxies that quantify cold season temperature, especially in Arctic regions that were devoid of continental ice sheets during the Holocene. Here, we present a new 16,000-year winter-spring temperature reconstruction derived from the unsaturation ratio of alkenones (U-3(7)K) in a continuous sedimentary sequence from Lake E5, northern Alaska. We employ a thermodynamic lake model to convert alkenone-inferred lake temperatures into winter-spring air temperature anomalies and we contextualize our proxy reconstruction with climate model output from the region. Our reconstruction shows that winter-spring temperatures warmed rapidly during the deglaciation at 16 and 14 thousand years before present and continued to warm gradually throughout the middle and late Holocene (0.12-0.28 degrees C/thousand years) in concert with regional sea surface temperature and sea ice records. Our results are consistent with climate model simulations and we attribute Holocene warming to rising winter-spring insolation, radiative forcing from rising greenhouse gas concentrations and regional feedbacks. Our reconstructed cold season warming equaled or exceeded summer cooling according to a regional synthesis of temperature records, suggesting that seasonal biases in temperature reconstructions may account for proxy-model disagreements in Holocene temperature trends from Eastern Beringia. (C) 2020 Elsevier Ltd. All rights reserved.},
	keywords = {Alkenone, Beringia, Continental biomarkers, Holocene, North America, paleoclimatology, paleolimnology, Proxy data-model comparison, seasonality, Temperature reconstruction},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2020.106438},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0277379120304005},
	author = {Longo, William M. and Huang, Yongsong and Russell, James M. and Morrill, Carrie and Daniels, William C. and Giblin, Anne E. and Crowther, Josue}
}
@article {2637,
	title = {Evidence of Ice Age humans in eastern Beringia suggests early migration to North America},
	journal = {Quaternary Science Reviews},
	volume = {205},
	year = {2019},
	month = {Jan-02-2019},
	pages = {35 - 44},
	abstract = {Our understanding of the timing and pathway of human arrival to the Americas remains an important and polarizing topic of debate in archaeology and anthropology. Traditional consensus, supported by archaeological and paleoenvironmental data, favors a {\textquoteright}swift peopling{\textquoteright} of the Americas from Asia via the Bering Land Bridge during the last Glacial termination. More recent genetic data and archaeological finds have challenged this view, proposing the {\textquoteright}Beringian standstill hypothesis{\textquoteright} (BSH), wherein a population of proto-Americans migrated from Asia during, or even prior to the Last Glacial Maximum (LGM) and lived in Beringia for thousands of years before their eventual spread across the American continents. Using a sediment archive from Lake E5 (68.641667 degrees N, 149.457706 degrees W), located on Alaska{\textquoteright}s North Slope, we present new data supporting the BSH and shedding new light on the environmental impact of these early American populations. Fecal biomarkers support human presence in the environs of the lake, and our data demonstrate elevated biomass burning in this region during the last Glacial. Elevated burning defies the expectation that natural fires would be less frequent in the Arctic during the last Glacial, thereby suggesting human ignition as the likely culprit. Our data shed new light on the pathway and timing of human migration to the Americas and demonstrate the possibility of the sustainable coexistence of humans and the Ice Age megafauna in Beringia prior to their extinction. (C) 2018 Elsevier Ltd. All rights reserved.},
	keywords = {Beringia, charcoal, Fecal sterols, Last Glacial, Paleofire, Polycyclic aromatic hydrocarbons (PAHs)},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2018.12.003},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0277379118307716https://api.elsevier.com/content/article/PII:S0277379118307716?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0277379118307716?httpAccept=text/plain},
	author = {Vachula, Richard S. and Huang, Yongsong and Longo, William M. and Dee, Sylvia G. and Daniels, William C. and Russell, James M.}
}
@article {2517,
	title = {A major increase in winter snowfall during the middle Holocene on western Greenland caused by reduced sea ice in Baffin Bay and the Labrador Sea},
	journal = {Geophysical Research Letters},
	volume = {45},
	year = {2016},
	month = {Apr-05-2018},
	pages = {5302 - 5308},
	abstract = {Recent observations indicate that ice-ocean interaction drives much of the recent increase in mass loss from the Greenland Ice Sheet; however, the role of ocean forcing in driving past glacier change is poorly understood. To extend the observational record and our understanding of the ocean-cryosphere link, we used a multi-proxy approach that combines new data from proglacial lake sediments, C-14-dated in situ moss that recently emerged from beneath cold-based ice caps, and Be-10 ages to reconstruct centennial-scale records of mountain glacier activity for the past similar to 10 k. y. in West Greenland. Proglacial lake sediment records and C-14 dating of moss indicate the onset of Neoglaciation in West Greenland at ca. 5 ka with substantial snowline lowering and glacier expansion at ca. 3.7 ka followed by additional ice expansion phases at ca. 2.9, ca. 1.7, and ca. 1.4 ka and during the Little Ice Age. We find that widespread glacier growth at ca. 3.7 ka in West Greenland coincides with marked cooling and reduced strength of the West Greenland Current in Disko Bugt. The transition to cooler ocean conditions at ca. 3.7 ka identified in Disko Bugt is registered by marine proxy data farther afield in East Greenland and on the northwestern Icelandic shelf, implying large-scale paleoceanographic changes across the North Atlantic during this interval. The similarity between glacier change on West Greenland and multiple marine and terrestrial records across the North Atlantic suggests that glaciers are strongly influenced by changes in ocean circulation and consequently implies that the ocean-cryosphere teleconnection is a persistent feature of the Arctic system. 
},
	doi = {10.1002/2016GL068513},
	url = {http://doi.wiley.com/10.1002/2016GL068513},
	author = {Thomas, Elizabeth K. and Briner, Jason P. and Ryan-Henry, John J. and Huang, Yongsong}
}
@article { ISI:000281306000013,
	title = {Radiocarbon Dating of Individual Lignin Phenols: A New Approach for Establishing Chronology of Late Quaternary Lake Sediments},
	journal = {ANALYTICAL CHEMISTRY},
	volume = {82},
	number = {{17}},
	year = {2010},
	month = {SEP 1},
	pages = {7119-7126},
	type = {Article},
	abstract = {The reliability of chronology is a prerequisite for meaningful paleoclimate reconstructions from sedimentary archives. The conventional approach of radiocarbon dating bulk organic carbon in lake sediments is often hampered by the old carbon effect, i.e., the assimilation of ancient dissolved inorganic carbon (DIC) derived from carbonate bedrocks or other sources. Therefore, radiocarbon dating is ideally performed on organic compounds derived from land plants that use atmospheric CO(2) and rapidly delivered to sediments. We demonstrate that lignin phenols isolated from lake sediments using reversed phase high performance liquid chromatography (HPLC) can serve as effective (14)C dating materials for establishing chronology during the late Quaternary. We developed a procedure to purify lignin phenols, building upon a published method. By isolating lignin from standard wood reference substances, we show that our method yields pure lignin phenols and consistent ages as the consensus ages and that our procedure does not introduce radiocarbon contamination. We further demonstrate that lignin phenol ages are compatible with varve counted and macrofossil dated sediment horizons in Steel Lake and Fayetteville Green Lake. Applying the new method to lake sediment cores from Lake Qinghai demonstrates that lignin phenol ages in Lake Qinghai are consistently younger than bulk total organic carbon (TOC) ages which are contaminated by old carbon effect. We also show that the age offset between lignin and bulk organic carbon differs at different Lake Qinghai sedimentary horizons, suggesting a variable hard water effect at different times and that a uniform age correction throughout the core is inappropriate.},
	issn = {0003-2700},
	doi = {10.1021/ac100494m},
	author = {Hou, Juzhi and Huang, Yongsong and Brodsky, Corynn and Alexandre, Marcelo R. and McNichol, Ann P. and King, John W. and Hu, Feng Sheng and Shen, Ji}
}
@article {335,
	title = {Northern hemisphere controls on tropical southeast African climate during the past 60,000 years},
	journal = {Science},
	volume = {322},
	year = {2008},
	note = {id: 2047; PT: J; UT: WOS:000259902300046},
	pages = {252-255},
	abstract = {The processes that control climate in the tropics are poorly understood. We applied compound-specific hydrogen isotopes (delta D) and the TEX(86) (tetraether index of 86 carbon atoms) temperature proxy to sediment cores from Lake Tanganyika to independently reconstruct precipitation and temperature variations during the past 60,000 years. Tanganyika temperatures follow Northern Hemisphere insolation and indicate that warming in tropical southeast Africa during the last glacial termination began to increase similar to 3000 years before atmospheric carbon dioxide concentrations. delta D data show that this region experienced abrupt changes in hydrology coeval with orbital and millennial-scale events recorded in Northern Hemisphere monsoonal climate records. This implies that precipitation in tropical southeast Africa is more strongly controlled by changes in Indian Ocean sea surface temperatures and the winter Indian monsoon than by migration of the Intertropical Convergence Zone.},
	issn = {0036-8075},
	doi = {10.1126/science.1160485},
	author = {Tierney, Jessica E. and Russell, James M. and Huang, Yongsong and Damste, Jaap S. Sinninghe and Hopmans, Ellen C. and Cohen, Andrew S.}
}
@article {2192,
	title = {Mapping of C4 plant input from North West Africa into North East Atlantic Sediments},
	journal = {Geochimica et Cosmochima Acta},
	volume = {64},
	year = {2000},
	note = {id: 1777},
	month = {2000},
	pages = {3505-3513},
	author = {Huang, Yongsong and Dupont, Lydie and Sarnthein, Michael and Hayes, John M. and Eglinton, Geoffrey}
}
