| Title | High Arctic Holocene temperature record from the Agassiz ice cap and Greenland ice sheet evolution |
| |
| Author | Lecavalier, B S; Fisher, D A; Milne, G A; Vinther, B M; Tarasov, L; Huybrechts, P; Lacelle, D; Main, B ; Zheng, J; Bourgeois, J; Dyke, A S |
| Source | Proceedings of the National Academy of Sciences of the United States of America vol. 114, no. 23, 2017 p. 5952-5957, https://doi.org/10.1073/pnas.1616287114  Open
Access |
| Image |  |
| Year | 2017 |
| Alt Series | Natural Resources Canada, Contribution Series 20182284 |
| Publisher | Proceedings of the National Academy of Sciences |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf (Adobe® Reader®); html |
| Program | Climate
Change Geoscience Risk Analysis |
| Released | 2017 05 16 |
| Abstract | We present a revised and extended high Arctic air temperature reconstruction from a single proxy that spans the past ~12,000 y (up to 2009 CE). Our reconstruction from the Agassiz ice cap (Ellesmere
Island, Canada) indicates an earlier and warmer Holocene thermal maximum with early Holocene temperatures that are 4-5 ¡C warmer compared with a previous reconstruction, and regularly exceed contemporary values for a period of ~3,000 y. Our results
show that air temperatures in this region are now at their warmest in the past 6,800-7,800 y, and that the recent rate of temperature change is unprecedented over the entire Holocene. The warmer early Holocene inferred from the Agassiz ice core leads
to an estimated ?1 km of ice thinning in northwest Greenland during the early Holocene using the Camp Century ice core. Ice modeling results show that this large thinning is consistent with our air temperature reconstruction. The modeling results
also demonstrate the broader significance of the enhanced warming, with a retreat of the northern ice margin behind its present position in the mid Holocene and a ~25% increase in total Greenland ice sheet mass loss (~1.4 m sea-level equivalent)
during the last deglaciation, both of which have implications for interpreting geodetic measurements of land uplift and gravity changes in northern Greenland. |
| Summary | (Plain Language Summary, not published)
Snow deposits with atmospheric information, linking to climate and environmental changes. With modern technologies for detection of low-level
contaminants in samples, it is readily possible to detect atmospheric composition changes. Therefore, information of long-term climate and environmental changes can be retrieved from snow/ice in Canadian ice caps. With existing data sets from ice
cores and new updates to such data sets with firn cores from Agassiz Ice Cap, a study on polar amplification of climate warming was carried out. Results show, in the past ~12,000 years, polar amplification was stronger (4-5³C warmer). This means
high-latitude warming led to a larger response of the Greenland ice sheet, ~1 m equivalent to global mean sea levels since last glacial maximum. Results also show present air temperatures at Agassiz ice cap are at their warmest in the past
6,800-7,800 yrs and century-scale rates of temperature change in this region are at their highest since 11,700 yrs ago. |
| GEOSCAN ID | 310859 |
|
|