Most of the ice currently melting on Greenland only formed during the last few hundred years.
A new paper (Axford et al., 2019
) reveals NW Greenland’s “outlet glaciers were smaller than today from ~9.4 to 0.2 ka BP
” (9,400 to 200 years before 1950), and that “most of the land-based margin reached its maximum Holocene extent in the last millennium and likely the last few hundred years
The authors conclude:
“We infer based upon lake sediment organic and biogenic content that in response to declining temperatures, North Ice Cap reached its present-day size ~1850 AD, having been smaller than present through most of the preceding Holocene
Furthermore, the authors assert Greenland was 2.5°C to 3°C warmer than modern on average during the Holocene Thermal Maximum, and peak temperatures were 4°C to 7°C warmer.
Another new paper ( Schweinsberg et al., 2019
) indicates the most pronounced glacier expansion in West Greenland has occurred during the last 2,000 years.
“Our records reveal asynchronous regrowth of GIC between ~4.3 and 2 ka emphasizing the variable responses of individual glaciers to late Holocene climate changes on Nuussuaq. The subsequent millennia were characterized by gradually increasing glacier size in accordance with gradual declining summer insolation. Superimposed on the progressive increase in glacier growth are frequent, high-amplitude GIC fluctuations throughout the late Holocene; the most significant periods of GIC expansion occurred at ~3.7 and 2.8 ka, and throughout the past ~2 ka.”
The authors cite a Greenland Ice Sheet temperature reconstruction showing modern temperatures (extending through 2015) are not unusual in the context of the last 10,000 years.
The source for the Schweinsberg et al. (2019) Greenland temperature reconstruction is Kobashi et al., 2017
, who concluded a) Greenland was about 2.9°C warmer than today during the Early Holocene, b) there has been no obvious net warming since the 1930s, and a c) slight cooling trend since 2005 (in accord with North Atlantic cooling).
This article appeared on the NoTricksZone website at https://notrickszone.com/2019/08/05/for-nearly-all-of-the-last-10000-years-greenland-ice-sheet-and-glacier-volume-was-smaller-than-today/