@article {edgerton_evaluating_2024,
	title = {Evaluating middle to late Holocene climate variability from δ18O of aquatic invertebrate remains in southwestern Greenland},
	journal = {Quaternary Science Reviews},
	volume = {333},
	year = {2024},
	month = {06/2024},
	pages = {108664},
	abstract = {Holocene paleotemperature records from ice-free margins of Greenland suggest spatiotemporal heterogeneity in the timing of key climate transitions following retreat of the Greenland Ice Sheet. However, the paucity of high-resolution climate records from this region limits our understanding of the timing, spatial variation, and drivers of Holocene climate variability. Here, we present a middle to late Holocene climate reconstruction based on δ18O of aquatic invertebrate (chironomid and cladoceran) remains and sediment geochemistry from lake sediments to elucidate millennial to submillennial-scale drivers of climate in southwestern Greenland. We establish that our site, Arrowhead Lake, is a through-flowing basin with an integrated signal of annual meteoric water with no evidence of significant evaporative enrichment. Core sediment geochemistry captures the transition from minerogenic-dominated to organic-rich sediments \~{}8~cal ka BP. Chitin-based δ18O measurements of both chironomid head capsules and ephippia exhibit similar temporal variability through the record, broadly decreasing from 8.2~cal ka BP to present, concurrent with decreasing summer insolation and regional Neoglacial cooling. A simplified assumption that temperature is the sole driver of changes in isotopes of precipitation yields an estimated average temperature change from the middle to late Holocene at Arrowhead Lake of 2.1{\textendash}3.0~{\textdegree}C, comparable to existing estimates of middle to late Holocene temperature decline in western Greenland. Depleted δ18O values after 3.3~cal ka BP correspond to the onset of Neoglacial cooling and independent evidence for a slowdown of the West Greenland Current, and suggests that both temperature and sea-ice variability were important controls on isotopic variability at this site. Highly depleted isotopic values at 8.2~cal ka BP followed by high isotopic variability in the early part of the middle Holocene suggests that our record may capture regional 8.2 ka cooling. This new isotope record provides insight into climate influences during the middle and late Holocene along the western Greenland margin that are important for understanding how ongoing melt of the Greenland Ice Sheet and amplified warming in the Arctic may impact the climate system.},
	keywords = {Chitin, Greenland, Holocene, paleoclimatology, Stable isotopes, δO},
	issn = {0277-3791},
	doi = {10.1016/j.quascirev.2024.108664},
	url = {https://www.sciencedirect.com/science/article/pii/S0277379124001653},
	author = {Edgerton, Briana A. and Axford, Yarrow and Chipman, Melissa L.}
}
@article {puleo_duration_2023,
	title = {Duration and ice thickness of a Late Holocene outlet glacier advance near Narsarsuaq, southern Greenland},
	journal = {Climate of the Past},
	volume = {19},
	number = {9},
	year = {2023},
	note = {Publisher: Copernicus GmbH},
	month = {09/2023},
	pages = {1777{\textendash}1791},
	abstract = {Greenland Ice Sheet (GrIS) outlet glaciers are currently losing mass, leading to sea level rise. Reconstructions of past outlet glacier behavior through the Holocene help us better understand how they respond to climate change. Kiattuut Sermiat, a southern Greenland outlet glacier near Narsarsuaq, is known to have experienced an unusually large Late Holocene advance that culminated at \~{}1600 cal yr BP and exceeded the glacier{\textquoteright}s Little Ice Age extent. We report sedimentary records from two lakes at slightly different elevations in an upland valley adjacent to Kiattuut Sermiat. These reveal when the outlet glacier{\textquoteright}s surface elevation was higher than during the Little Ice Age and constrain the associated outlet glacier surface elevation. We use bulk sediment geochemistry, magnetic susceptibility, color, texture, and the presence of aquatic plant macrofossils to distinguish between till, glaciolacustrine sediments, and organic lake sediments. Our 14C results above basal till recording regional deglaciation skew slightly old due to a reservoir effect but are generally consistent with regional deglaciation occurring \~{} 11 000 cal yr BP. Neoglacial advance of Kiattuut Sermiat is recorded by deposition of glaciolacustrine sediments in the lower-elevation lake, which we infer was subsumed by an ice-dammed lake that formed along the glacier{\textquoteright}s margin just after \~{} 3900 cal yr BP. This timing is consistent with several other glacial records in Greenland showing neoglacial cooling driving advance between \~{} 4500{\textendash}3000 cal yr BP. Given that glaciolacustrine sediments were deposited only in the lower-elevation lake, combined with glacial geomorphological evidence in the valley containing these lakes, we estimate the former ice margin{\textquoteright}s elevation to have been \~{} 670 m a.s.l., compared with \~{} 420 m a.s.l. today. The ice-dammed lake persisted until the glacier surface fell below this elevation at \~{} 1600 cal yr BP. The retreat timing contrasts with overall evidence for cooling and glacier advance in the region at that time, so we infer that Kiattuut Sermiat{\textquoteright}s retreat may have resulted from reduced snowfall amounts and/or local glaciological complexity. High sensitivity to precipitation changes could also explain the relatively limited Little Ice Age advance of Kiattuut Sermiat compared with the earlier neoglacial advance.},
	issn = {1814-9324},
	doi = {10.5194/cp-19-1777-2023},
	url = {https://cp.copernicus.org/articles/19/1777/2023/},
	author = {Puleo, Peter J. K. and Axford, Yarrow}
}
@article {puleo_younger_2022,
	title = {Younger Dryas and early Holocene climate in south Greenland inferred from oxygen isotopes of chironomids, aquatic Moss, and Moss cellulose},
	journal = {Quaternary Science Reviews},
	volume = {296},
	year = {2022},
	month = {11/2022},
	pages = {107810},
	abstract = {Ice core records have long indicated that the Younger Dryas began and ended with large, abrupt climate shifts over Greenland. Key climatic features remain unknown, including the magnitude of warming during the Younger Dryas-Holocene transition along with the seasonality and spatial variability of Younger Dryas climate changes across Greenland. Here, we use geochemical and paleoecological proxies from lake sediments at Lake N14 in south Greenland to address these outstanding questions. Radiocarbon dating and diatom assemblages confirm early deglaciation and isolation of Lake N14 before \~{}13,600~cal~yr BP, consistent with previous work. Oxygen isotope ratios (δ18O) of chironomid head capsules, bulk aquatic moss, and aquatic moss-derived cellulose are used to reconstruct oxygen isotopes of past lake water and annual precipitation. Oxygen isotope proxies indicate annual precipitation δ18O values increased by 5.9{\textendash}7.7{\textperthousand} at the end of the Younger Dryas. Following the Younger Dryas, moss and cellulose δ18O values show a clear decline in precipitation δ18O values of 2{\textendash}3{\textperthousand} from \~{}11,540{\textendash}11,340~cal~yr BP that may correspond with the Preboreal Oscillation. Reconstructed precipitation δ18O values then gradually increased from 11,300{\textendash}10,100~cal~yr BP. All three aquatic organic materials register similar shifts in precipitation δ18O values over time, and they closely parallel the δ18O shifts observed in ice cores. This evidence strongly supports the utility of these methods for reconstructing lake water δ18O, and furthermore precipitation δ18O values where lake water reflects precipitation. The relatively large shift in isotopic composition of precipitation at Lake N14 suggests that shifts in temperature, precipitation seasonality, and/or moisture sources at the end of the Younger Dryas were even larger in south Greenland than they were in central Greenland, most likely because of the proximity to major changes in North Atlantic Ocean circulation. The annual air temperature change estimated at Lake N14 at the end of the Younger Dryas is also very large (\~{}18~{\textpm}~7~{\textdegree}C) compared to the summer warming previously inferred from chironomid species assemblages there (\~{}6~{\textdegree}C). This indicates that the strongest warming at the end of the Younger Dryas occurred in the winter season, consistent with past observations of intensified Younger Dryas seasonality at Lake N14 and elsewhere in Greenland.},
	keywords = {Chironomids, Deglaciation, diatoms, Greenland, Holocene, Micropaleontology, paleoclimatology, paleolimnology, Stable isotopes, Younger Dryas},
	issn = {0277-3791},
	doi = {10.1016/j.quascirev.2022.107810},
	url = {https://www.sciencedirect.com/science/article/pii/S0277379122004413},
	author = {Puleo, Peter J. K. and Masterson, Andrew L. and Medeiros, Andrew S. and Schellinger, Grace and Steigleder, Regan and Woodroffe, Sarah and Osburn, Magdalena R. and Axford, Yarrow}
}
@article {2688,
	title = {Holocene temperature and landscape history of southwest Greenland inferred from isotope and geochemical lake sediment proxies},
	journal = {Quaternary Science Reviews},
	volume = {239},
	year = {2020},
	month = {Jan-07-2020},
	pages = {106358},
	abstract = {Terrestrial temperature reconstructions from the ice-free margins of Greenland are critical for constraining the sensitivity of the Greenland ice sheet to past climate change. Numerous investigations have clarified the glacial history of southwest Greenland in recent decades; however, very few local quantitative temperature reconstructions exist as context for changes in the cryosphere. We examine sedimentary records from two lakes south of Nuuk, Greenland (informally named lakes T1 and T2), and investigate millennial scale Holocene climate change using a multi-proxy approach. Changes in X-Ray fluorescence spectroscopy (XRF), δ15N, δ13C and biogenic silica concentrations of bulk lake sediments mark the transition from a marine environment to isolated lakes as relative sea level fell in the early Holocene. δ18O values of subfossil insects (chironomids) from lakes T1 and T2 decreased by 2{\textendash}3{\textperthousand} from c. 8.8 ka BP (minimum limiting age for the onset of lacustrine sediment deposition in lake T2; ka BP = thousands of years before 1950) to 1 ka BP. Existing isotope-independent temperature reconstructions from the west coast of Greenland suggest that these changes in δ18O values accompanied gradual cooling of 2{\textendash}4 {\textdegree}C, concomitant with decreasing summer insolation. There is widespread regional evidence that this cooling resulted in progressive regrowth of local glaciers and of the ice sheet. The regional consensus on the magnitude of this temperature change indicates that the local, modern modeled temperature - precipitation δ18O relationship cannot be used to quantify millennial-scale temperature changes at these sites through the Holocene. This reinforces that studies utilizing δ18O-based proxies to infer temperature change should carefully assess local isotope-temperature relationships over space and time.},
	keywords = {Chironomids, glaciers, Greenland, Isolation basins, lake sediments, oxygen isotopes, Paleotemperatures, Stable isotopes},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2020.106358},
	url = {https://www.sciencedirect.com/science/article/pii/S0277379120303206},
	author = {Lasher, G. Everett and Axford, Yarrow and Masterson, Andrew L. and Berman, Karalyn and Larocca, Laura J.}
}
@article {2690,
	title = {Late glacial and Holocene paleoenvironments in the midcontinent United States, inferred from Geneva Lake leaf wax, ostracode valve, and bulk sediment chemistry},
	journal = {Quaternary Science Reviews},
	volume = {241},
	year = {2020},
	month = {Jan-08-2020},
	pages = {106384},
	abstract = {Geneva Lake in Wisconsin, USA, is > 20,000 years old and contains a 30-m thick lacustrine sediment record of mid-continent North American climate and environmental change. Here we describe a sediment record from Geneva Lake spanning the past 14,500 years. From scanning X-ray fluorescence, organic C and N concentrations and isotopes, X-ray diffraction, magnetic susceptibility, and grain size of bulk sediments, we infer changes in sediment sources over time including: abrupt decline in inputs of remobilized loess \~{}13,400 cal yr BP followed by a gradual transition to organic-rich marl deposition by \~{}10,400 cal yr BP as the landscape stabilized following a period of permafrost thaw and vegetation development; deposition of a minerogenic unit at \~{}8,200 cal yr BP that may record enhanced eolian activity during the widespread {\textquotedblleft}8.2 ka event; {\textquotedblright} and elevated zinc, lead, and arsenic from human activities following regional industrialization. Within the Holocene marl, we also use isotopic (δ18O and δ13C) and trace metal ratio (Sr/Ca and Mg/Ca) analyses of ostracode valves paired with concentrations and hydrogen isotopic composition (δ2H) of leaf wax n-alkanes to infer climate and hydrological change. Groundwater had a large but declining influence on lake water chemistry from 11,800 to 9,700 cal yr BP, precluding inferences of regional climate from our lacustrine proxies during this period. δ2H values of terrestrial n-C29 alkanes show little variability from 9,700 to present, indicating the average isotopic composition of local precipitation was relatively stable, reflecting stable condensation temperatures and source. In contrast, a gradual trend towards more δ18O- and δ2H-depleted lake water and lower lake water Sr/Ca from 9700 cal yr BP to present suggest decreasing evaporation of lake water and increasing precipitation amounts throughout the Holocene and resulting shorter lake water residence times. Lake water Mg/Ca variations over the past 9,700 years broadly parallel regional pollen-based reconstructions of summer temperatures. Neither Mg/Ca nor terrestrial leaf wax δ2H suggest long-term directional shifts in temperature at this site through the middle to late Holocene, as climate became wetter. It appears that precipitation isotopes did not track local temperatures on millennial timescales in this part of mid-continent North America through the Holocene, and instead may have covaried with changes in Northern Hemisphere latitudinal temperature gradients driven by large Arctic temperature changes.},
	keywords = {Holocene, Inorganic geochemistry, Loess, North America, Organic geochemistry, paleoclimatology, paleolimnology, Pleistocene, sedimentology, Stable isotopes},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2020.106384},
	url = {https://www.sciencedirect.com/science/article/pii/S0277379120303462},
	author = {Puleo, Peter J.K. and Axford, Yarrow and McFarlin, Jamie M. and Curry, B. Brandon and Barklage, Mitchell and Osburn, Magdalena R.}
}
@article {2689,
	title = {Local glaciers record delayed peak Holocene warmth in south Greenland},
	journal = {Quaternary Science Reviews},
	volume = {241},
	year = {2020},
	month = {Jan-08-2020},
	pages = {106421},
	abstract = {Local glaciers and ice caps (GICs) respond sensitively and quickly, on the scale of decades to centuries, to climate variations. Continuous records of past fluctuations in GIC size provide information on the timing and magnitude of Holocene climate shifts, and a longer-term perspective on 21st century glacier retreat. Although there is broad-scale agreement on millennial-scale trends in Holocene climate variability and fluctuations in local GICs in Greenland, regional variations are only loosely constrained. Here we present three Holocene proglacial lake sediment records from South Greenland, an area with abundant local glaciers but few Holocene-length paleoclimate records. In addition, we use geospatial analysis to model past equilibrium-line altitudes (ELAs) and thereby constrain the magnitude of ablation-season temperature change during the warmest and coolest periods of the Holocene. Physical and geochemical sedimentary characteristics show that two of the proglacial lakes continued to receive glacial meltwater input until \~{}7.3 and \~{}7.1 ka BP. The survival of local glaciers implies that South Greenland remained relatively cool, and that summer temperatures gradually warmed, but did not warm well beyond 1.2 {\textdegree}C above present in the early Holocene. In the mid-Holocene, from \~{}7.1 to 5.5 ka BP, organic sedimentation at these two sites indicates that local glaciers became very small, or more likely melted away completely. The glaciers within the third lake{\textquoteright}s catchment melted away prior to \~{}5.2 ka BP, as sediments deposited earlier in the Holocene could not be dated at this site. We estimate that summer temperatures increased by at least 1.2{\textendash}1.8 {\textdegree}C above present by \~{}7.3{\textendash}7.1 ka BP. Our results are consistent with other observations that suggest a north-to-south gradient in the timing of Holocene thermal maximum conditions, with southern Greenland experiencing a delayed warming relative to other regions in Greenland. As summer temperatures cooled in the Neoglacial, our records show that sustained glacier regrowth began \~{}3.1 ka BP with glaciers in the southernmost catchment, which at present, receive the most precipitation. In the other two catchments, which host smaller glaciers in a drier environment, regrowth began at \~{}1.3 and \~{}1.2 ka BP, the timing of which is in agreement with other glacial records from the Arctic Atlantic region. Local glaciers reached their maximum late Holocene extents during a cooler, second phase of the Little Ice Age (LIA) \~{}0.2-0.1 ka BP, that we estimate was at least 0.4{\textendash}0.9 {\textdegree}C cooler than present. Overall, these findings improve understanding of the spatio-temporal dynamics of Holocene glacier and climate change in Greenland, potentially yielding valuable information about their future response.},
	keywords = {Equilibrium-line altitudes, Greenland, Holocene thermal maximum, lake sediments, Little ice age, Mountain glaciers, Paleotemperatures},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2020.106421},
	url = {https://www.sciencedirect.com/science/article/pii/S0277379120303838},
	author = {Larocca, Laura J. and Axford, Yarrow and Bj{\o}rk, Anders A. and Lasher, G. Everett and Brooks, Jeremy P.}
}
@article {2687,
	title = {Medieval warmth confirmed at the Norse Eastern Settlement in Greenland},
	journal = {Geology},
	volume = {47},
	year = {2019},
	month = {Jan-03-2019},
	pages = {267 - 270},
	abstract = {Recent work has documented glacier advances in West Greenland coincident with the Medieval Climate Anomaly (MCA) and warmth across much of northern Europe. The North Atlantic Oscillation (NAO) has been invoked to explain antiphasing of temperatures between these North Atlantic regions. Historical and model observations suggest negative correlation between the mode of NAO and both temperature and δ18O values of precipitation over much of Greenland. We test for a hypothesized positive NAO mode and associated cool conditions during the MCA in South Greenland within the Norse Eastern Settlement by reconstructing δ18O values of precipitation at subcentennial resolution over the past 3000 yr using aquatic insect subfossils preserved in lake sediments. More positive δ18O values are found between 900 and 1400 CE, indicating a period of warmth in South Greenland superimposed on late Holocene insolation-forced Neoglacial cooling, and thus not supporting a positive NAO anomaly during the MCA. Highly variable δ18O values record an unstable climate at the end of the MCA, preceding Norse abandonment of Greenland. The spatial pattern of paleoclimate in this region supports proposals that North Atlantic subpolar ocean currents modulated South Greenland{\textquoteright}s climate over the past 3000 yr, particularly during the MCA. Terrestrial climate in the Labrador Sea and Baffin Bay regions may be spatially heterogeneous on centennial time scales due in part to the influence of the subpolar gyre.},
	issn = {0091-7613},
	doi = {10.1130/G45833.110.1130/2019096},
	url = {https://pubs.geoscienceworld.org/gsa/geology/article/47/3/267/568708/Medieval-warmth-confirmed-at-the-Norse-Easternhttps://pubs.geoscienceworld.org/gsa/geology/article-pdf/47/3/267/4650216/267.pdfhttps://www.geosociety.org/datarepository/2019096},
	author = {Lasher, G. Everett and Axford, Yarrow}
}
@article {2685,
	title = {Holocene history of the Greenland Ice-Sheet margin in Northern Nunatarssuaq, Northwest Greenland},
	journal = {arktos},
	volume = {4},
	year = {2018},
	month = {Jan-12-2018},
	abstract = {Records of past Greenland Ice-Sheet (GrIS) extents are important for understanding the response of the ice sheet to climate conditions, providing a longer term perspective on present ice-margin fluctuations, and evaluating ice-sheet models. We present a record of Holocene GrIS extents in Nunatarssuaq, Northwest Greenland, based on geomorphic mapping combined with 10Be surface exposure dating of rock surfaces and 14C dating of subfossil plants. 10Be ages of boulders and bedrock exposed during deglaciation from the Last Glacial Maximum range from ~ 81 to 15 ka. The apparently old ages of some samples and scatter in the dataset indicate the presence of 10Be inherited from prior periods of exposure and suggest that overriding ice was minimally erosive. Subfossil plants exposed on a debris band in the GrIS margin date to ~ 4.7 cal ka BP and register a time when the Northwest GrIS was smaller than at present. Geomorphic evidence, including a drift sheet, grounding-line moraines, and higher levels of Nords{\o}, document an advance of the Nuna and Tunge Rampen (GrIS outlet glaciers). 14C ages of in situ subfossil plants and 10Be ages of boulders bracket this advance to ~ 3.2{\textendash}2.1 ka, a period of regional cooling. Unweathered, lichen-free drift occurs < 50 m beyond the present GrIS margin in most locations. 10Be ages of this drift are 2.2{\textendash}0.5 ka and likely contain inherited nuclides. 14C ages of in situ subfossil plants atop this drift are between cal AD ~ 1640 and 2001, suggesting recent ice-margin fluctuations.},
	issn = {2364-9453},
	doi = {10.1007/s41063-018-0044-0},
	url = {http://link.springer.com/10.1007/s41063-018-0044-0http://link.springer.com/content/pdf/10.1007/s41063-018-0044-0.pdfhttp://link.springer.com/article/10.1007/s41063-018-0044-0/fulltext.htmlhttp://link.springer.com/content/pdf/10.1007/s41063-018-0044-0.pdf},
	author = {Farnsworth, Lauren B. and Kelly, Meredith A. and Bromley, Gordon R. M. and Axford, Yarrow and Osterberg, Erich C. and Howley, Jennifer A. and Jackson, Margaret S. and Zimmerman, Susan R.}
}
@article {2686,
	title = {Pronounced summer warming in northwest Greenland during the Holocene and Last Interglacial},
	journal = {Proceedings of the National Academy of Sciences},
	volume = {115},
	year = {2018},
	month = {Jul-06-2019},
	pages = {6357 - 6362},
	abstract = {Projections of future rates of mass loss from the Greenland Ice Sheet are highly uncertain because its sensitivity to warming is unclear. Geologic reconstructions of Quaternary interglacials can illustrate how the ice sheet responded during past warm periods, providing insights into ice sheet behavior and important tests for data-model comparisons. However, paleoclimate records from Greenland are limited: Early Holocene peak warmth has been quantified at only a few sites, and terrestrial sedimentary records of prior interglacials are exceptionally rare due to glacial erosion during the last glacial period. Here, we discuss findings from a lacustrine archive that records both the Holocene and the Last Interglacial (LIG) from Greenland, allowing for direct comparison between two interglacials. Sedimentary chironomid assemblages indicate peak July temperatures 4.0 to 7.0 {\textdegree}C warmer than modern during the Early Holocene maximum in summer insolation. Chaoborus and chironomids in LIG sediments indicate July temperatures at least 5.5 to 8.5 {\textdegree}C warmer than modern. These estimates indicate pronounced warming in northwest Greenland during both interglacials. This helps explain dramatic ice sheet thinning at Camp Century in northwest Greenland during the Early Holocene and, for the LIG, aligns with controversial estimates of Eemian warming from ice core data retrieved in northern Greenland. Converging geologic evidence for strong LIG warming is challenging to reconcile with inferred Greenland Ice Sheet extent during the LIG, and the two appear incompatible in many models of ice sheet evolution. An increase in LIG snowfall could help resolve this problem, pointing to the need for hydroclimate reconstructions from the region.},
	issn = {0027-8424},
	doi = {10.1073/pnas.1720420115},
	url = {http://www.pnas.org/lookup/doi/10.1073/pnas.1720420115https://syndication.highwire.org/content/doi/10.1073/pnas.1720420115http://www.pnas.org/syndication/doi/10.1073/pnas.1720420115},
	author = {McFarlin, Jamie M. and Axford, Yarrow and Osburn, Magdalena R. and Kelly, Meredith A. and Osterberg, Erich C. and Farnsworth, Lauren B.}
}
@article {2601,
	title = {Holocene temperatures and isotopes of precipitation in Northwest Greenland recorded in lacustrine organic materials},
	journal = {Quaternary Science Reviews},
	volume = {170},
	year = {2017},
	month = {Jan-08-2017},
	pages = {45 - 55},
	abstract = {Reconstructions of Holocene lake water isotopic composition based upon subfossil aquatic organic material offer new insights into Arctic
climate. We present quantitative estimates of warmth during the Holocene Thermal Maximum in northwest Greenland, inferred from oxygen isotopes of chironomid head capsules and aquatic moss preserved in lake sediments. delta O-18 values of chironomids from surface sediments of multiple Greenland lakes indicate that these subfossil remains record the delta O-18 values of the lake water in which they grow. Our lake water delta O-18 reconstruction is supported by downcore agreement with delta O-18 values in aquatic moss and chironomid remains. delta O-18 of both organic materials from Secret Lake decrease after 4 ka (ka = thousands of years ago) by 3 parts per thousand into the Neoglacial. We argue that lake water at Secret Lake primarily reflects precipitation delta O-18 values, which is strongly correlated with air temperature in NW Greenland, and that this signal is biased towards summer and early autumn conditions. Other factors may have influenced Secret Lake delta O-18 values through the Holocene, including evaporation of lake water and changing seasonality and source of precipitation. The maximum early Holocene summer and early autumn-biased temperature anomaly at Secret Lake is 2.5-4 degrees C warmer than present from 7.7 (the beginning of our record) to similar to 6 ka. The maximum late Holocene cold anomaly (which includes the Little Ice Age) is 1.5-3 degrees C colder than present. These ranges of possible temperature anomalies reflect uncertainty in the delta O-18 temperature relationship for precipitation at the study site through the Holocene. (C) 2017 Elsevier Ltd. All rights reserved.},
	keywords = {Chironomids, Greenland, Holocene, paleoclimatology, paleolimnology, Stable isotopes},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2017.06.016},
	url = {http://linkinghub.elsevier.com/retrieve/pii/S0277379116305650http://api.elsevier.com/content/article/PII:S0277379116305650?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S0277379116305650?httpAccept=text/plain},
	author = {Lasher, G. Everett and Axford, Yarrow and McFarlin, Jamie M. and Kelly, Meredith A. and Osterberg, Erich C. and Berkelhammer, Max B.}
}
@article {2610,
	title = {Timing and magnitude of early to middle Holocene warming in East Greenland inferred from chironomids},
	journal = {Boreas},
	volume = {4611126123715949514747452279282108875423653331285492025312166523481473253855431029263383391243655482254028102024461441564827316},
	year = {2017},
	month = {Jan-10-2017},
	pages = {678 - 687},
	abstract = {Much of Greenland experienced summers warmer than present in parts of the early to middle Holocene, during a precession-driven positive anomaly in summer insolation. However, the magnitude of that warmth remains poorly known, and its timing and spatial pattern are uncertain. Here we describe the first quantitative Holocene palaeotemperature reconstruction from central East Greenland based upon insect (chironomid) assemblages preserved in lake sediments. We postulate that landscapes like our study site, characterized by minimal soil and vegetation development through the Holocene and thus little influenced by some important secondary gradients, are especially well suited to the use of chironomids to reconstruct Holocene temperatures. The inferred timing of warmth at our study site near Scoresby Sund agrees well with other nearby evidence, including glacial geological reconstructions and temperatures inferred from precipitation isotopes at Renland ice cap, supporting the use of chironomids to reconstruct temperatures at this site. We infer highest temperatures from c. 10 to 5.5 ka, followed by gradual cooling after 5.5 ka and progressively colder and less productive conditions after 3.5 ka. Models based upon two independent training sets yield similar inferred temperature trends, and suggest an average summer temperature anomaly from c. 10 to 5.5 ka of 3 to 4 {\textdegree}C relative to the preindustrial last millennium. The estimated overall rate of Neoglacial cooling averaged over the period from 5.5 to 0.5 ka was 0.6 to 0.8 {\textdegree}C per thousand years, more than twice the rate previously estimated for the Arctic as a whole. Given strong apparent spatial variability in Holocene climate around the Arctic, and the utility of palaeoclimate data for improving climate and ice-sheet models, it should be a priority to further quantify past temperature changes around the margins of the Greenland Ice Sheet, where few quantitative reconstructions exist and future warming will affect global sea level. },
	doi = {10.1111/bor.2017.46.issue-410.1111/bor.12247},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/bor.12247},
	author = {Axford, Yarrow and Levy, Laura B. and Kelly, Meredith A. and Francis, Donna R. and Hall, Brenda L. and Langdon, Peter G. and Lowell, Thomas V.},
	editor = {{\'\i}nguez-Rodrigo, M. and Baquedano, E. and Mabulla, A. and {\'\i}n, F. and Egeland, C. P.}
}
@article {2522,
	title = {Holocene temperature history at the western Greenland Ice Sheet margin reconstructed from lake sediments},
	journal = {Quaternary Science Reviews},
	volume = {59},
	year = {2013},
	month = {Jan-01-2013},
	pages = {87 - 100},
	abstract = {Predicting the response of the Greenland Ice Sheet to future climate change presents a major challenge to climate science. Paleoclimate data from Greenland can provide empirical constraints on past cryospheric responses to climate change, complementing insights from contemporary observations and from modeling. Here we examine sedimentary records from five lakes near Jakobshavn Isbr{\ae} in central West Greenland to investigate the timing and magnitude of major Holocene climate changes, for comparison with glacial geologic reconstructions from the region. A primary objective of this study is to constrain the timing and magnitude of maximum warmth during the early to middle Holocene positive anomaly in summer insolation. Temperature reconstructions from subfossil insect (chironomid) assemblages suggest that summer temperatures were warmer than present by at least 7.1 ka (the beginning of the North Lake record; ka = thousands of years before present), and that the warmest millennia of the Holocene occurred in the study area between 6 and 4 ka. Previous studies in the Jakobshavn region have found that the local Greenland Ice Sheet margin was most retracted behind its present position between 6 and 5 ka, and here we use chironomids to estimate that local summer temperatures were 2{\textendash}3 {\textdegree}C warmer than present during that time of minimum ice sheet extent. As summer insolation declined through the late Holocene, summer temperatures cooled and the local ice sheet margin expanded. Gradual, insolation-driven millennial-scale temperature trends in the study area were punctuated by several abrupt climate changes, including a major transient event recorded in all five lakes between 4.3 and 3.2 ka, which overlaps in timing with abrupt climate changes previously documented around the North Atlantic region and farther afield at \~{}4.2 ka.},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2012.10.024},
	url = {https://doi.org/10.1016/j.quascirev.2012.10.024},
	author = {Axford, Yarrow and Losee, Shanna and Briner, Jason P. and Francis, Donna R. and Langdon, Peter G. and Walker, Ian R.}
}
@article {2524,
	title = {Response of a marine-terminating Greenland outlet glacier to abrupt cooling 8200 and 9300 years ago},
	journal = {Geophysical Research Letters},
	volume = {38},
	year = {2011},
	month = {Apr-12-2013},
	pages = {n/a - n/a},
	abstract = {Long-term records of Greenland outlet-glacier change extending beyond the satellite era can inform future predictions of Greenland Ice Sheet behavior. Of particular relevance is elucidating the Greenland Ice Sheet{\textquoteright}s response to decadal- and centennial-scale climate change. Here, we reconstruct the early Holocene history of Jakobshavn Isbr{\ae}, Greenland{\textquoteright}s largest outlet glacier, using 10Be surface exposure ages and 14C-dated lake sediments. Our chronology of ice-margin change demonstrates that Jakobshavn Isbr{\ae} advanced to deposit moraines in response to abrupt cooling recorded in central Greenland ice cores ca. 8,200 and 9,300 years ago. While the rapid, dynamically aided retreat of many Greenland outlet glaciers in response to warming is well documented, these results indicate that marine-terminating outlet glaciers are also able to respond quickly to cooling. We suggest that short lag times of high ice flux margins enable a greater magnitude response of marine-terminating outlets to abrupt climate change compared to their land-terminating counterparts.},
	doi = {10.1029/2011GL049639},
	url = {http://doi.wiley.com/10.1029/2011GL049639},
	author = {Young, {\'a}s E. and Briner, Jason P. and Axford, Yarrow and Csatho, Beata and Babonis, Greg S. and Rood, Dylan H. and Finkel, Robert C.}
}
