Holocene climate change in Arctic Canada and Greenland

Abstract

This synthesis paper summarizes published proxy climate evidence showing the spatial and temporal pattern of climate change through the Holocene in Arctic Canada and Greenland. Our synthesis includes 47 records from a recently published database of highly resolved Holocene paleoclimate time series from the Arctic (Sundqvist et al., 2014). We analyze the temperature histories represented by the database and compare them with paleoclimate and environmental information from 54 additional published records, mostly from datasets that did not fit the selection criteria for the Arctic Holocene database. Combined, we review evidence from a variety of proxy archives including glaciers (ice cores and glacial geomorphology), lake sediments, peat sequences, and coastal and deep-marine sediments. The temperature-sensitive records indicate more consistent and earlier Holocene warmth in the north and east, and a more diffuse and later Holocene thermal maximum in the south and west. Principal components analysis reveals two dominant Holocene trends, one with early Holocene warmth followed by cooling in the middle Holocene, the other with a broader period of warmth in the middle Holocene followed by cooling in the late Holocene. The temperature decrease from the warmest to the coolest portions of the Holocene is 3.0 ± 1.0 C on average (n ¼ 11 sites). The Greenland Ice Sheet retracted to its minimum extent between 5 and 3 ka, consistent with many sites from around Greenland depicting a switch from warm to cool conditions around that time. The spatial pattern of temperature change through the Holocene was likely driven by the decrease in northern latitude summer insolation through the Holocene, the varied influence of waning ice sheets in the early Holocene, and the variable influx of Atlantic Water into the study region.

Greenland‐Wide Seasonal Temperatures During the Last Deglaciation

“…Recently, Lecavalier et al (2017) suggested that the timing of the HTM is earlier (11-10 ka BP) on Ellesmere Island, based on elevation-corrected records of summer melt and water isotopes-at that same location our merged product suggests maximum HTM warmth to occur around 9.5 ka BP (Figure 2h). Our data-model merged product suggests HTM summer temperatures over Greenland are roughly 3.3 ∘ C above modern day-lower than melt-based reconstructions from Ellesmere Island (Lecavalier et al, 2017) of more than 5 ∘ C but in good agreement with the HTM reconstruction by Briner et al (2016) of 3 ± 1 ∘ C. Our data-model merged product suggests HTM summer temperatures over Greenland are roughly 3.3 ∘ C above modern day-lower than melt-based reconstructions from Ellesmere Island (Lecavalier et al, 2017) of more than 5 ∘ C but in good agreement with the HTM reconstruction by Briner et al (2016) of 3 ± 1 ∘ C.…”

Holocene environmental history in high‐Arctic North Greenland revealed by a combined biomarker and macrofossil approach

“…ka BP (Wagner & Bennike 2015). The timing of peak warmth agrees well with the average temperature trend across Greenland as compiled by Briner et al (2016). ka BP at 95 cm depth (the lowermost sample above the reworked zone 1) to c. 5.4 cal.…”

“…Mean summer insolation at 80°N was approximately 50 W m À2 higher during the Early Holocene (Greenlandian) insolation maximum compared to today and resulted in the Early to Middle Holocene thermal maximum (HTM) causing retreat and disappearance of the northern ice sheets except for the Greenland Ice Sheet (Berger & Loutre 1991;Ullman et al 2015). The recent compilation by Briner et al (2016) highlighted that the expression of the HTM and subsequent cooling is locally offset by up to c. 2 ka, but overall warming in North and East Greenland was more pronounced and preceded warming in southwest Greenland. The recent compilation by Briner et al (2016) highlighted that the expression of the HTM and subsequent cooling is locally offset by up to c. 2 ka, but overall warming in North and East Greenland was more pronounced and preceded warming in southwest Greenland.…”

The Onset and Rate of Holocene Neoglacial Cooling in the Arctic

“…This aligns with peak cooling onset times in the region between 6 and 5 ka (Figure 2e). 4-3 ka) is also the Holocene minimum extent of the Greenland Ice Sheet, with Neoglacial growth of the ice sheet beginning around this time (Briner et al, 2016). 8-7 ka) intervals of maximum warmth, whereas those to the south or west experienced peak warmth ca.…”