Wagner, B. and Bennike, O. 2015. Holocene environmental change in the Skallingen area, eastern North Greenland, based on a lacustrine record. Boreas 44: 45-59.
Working with a sediment core that Wagner et al. (2010) extracted from a lake named Lille Sneha So in the Skallingen area of eastern North Greenland, Wagner and Bennike (2015) developed an 8000-year environmental history of the region, based on what they describe as "a detailed study of biogeochemical proxies, head capsules of chironomid larvae, and macrofossils."
As a result of this effort, the two researchers determined that (1) "maximum concentrations of chironomids, maximum occurrence of ephippia of the water flea Daphnia pulex, highest organic matter contents and lowest minerogenic input from c. 7700 to 4400 cal. a BP probably reflect the Holocene thermal maximum (HTM)," that (2) "the highest temperatures during the HTM are indicated around 7000 cal. a BP, when Salix arctica, which is considered a warmth-loving plant, had a maximum," that (3) "comparisons with Holocene records from East and North Greenland show similar immigration histories and similar trends, with the Little Ice Age as the coldest period during the Holocene, culminating about 150 years ago," and that (4) "subsequent warming does not indicate environmental conditions comparable to the HTM yet at this stage."
So, at a time, today, when the air's CO2 concentration is approximately 400 ppm, it is still much cooler in Greenland than when the HTM held sway and the air's CO2 concentration was a mere 250 ppm. And, despite that extended period of warmer temperatures during the HTM, the Greenland ice sheet did not disappear. Yet some people are concerned that 21st century CO2 concentrations and temperatures are somehow going to melt the ice sheet and wreck havoc on sea levels??? Go figure!
Wagner, B., Bennike, O., Berg, S., Treu, D. and White, D. 2010. Paleoenvironmental studies in NE-Greenland. In: Jokat, W. (Ed.). The expedition of the research vessel 'Polarstern' to the Arctic in 2009 (ARK-XXIV/3). Reports on Polar and Marine Research 615: 78-97.