Younger-Dryas cooling and sea-ice feedbacks were prominent features of the Pleistocene-Holocene transition in Arctic Alaska
Declining sea-ice extent is currently amplifying climate warming in the Arctic. Instrumental records at high latitudes are too short-term to provide sufficient historical context for these trends, so paleoclimate archives are needed to better understand the functioning of the sea ice-albedo feedback...
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ftcollegewooster:oai:openworks.wooster.edu:facpub-1266 2023-05-15T13:11:31+02:00 Younger-Dryas cooling and sea-ice feedbacks were prominent features of the Pleistocene-Holocene transition in Arctic Alaska Gaglioti, Benjamin V. Mann, Daniel H. Wooller, Matthew J. Jones, Benjamin M. Wiles, Greg Groves, Pamela 2017-08-01T07:00:00Z https://openworks.wooster.edu/facpub/254 unknown Open Works https://openworks.wooster.edu/facpub/254 All Faculty Articles arctic Alaska paleoclimate oxygen isotopes climate change sea ice dendrochronology younger dryas North Pacific Bering Strait Geology text 2017 ftcollegewooster 2022-04-27T05:50:17Z Declining sea-ice extent is currently amplifying climate warming in the Arctic. Instrumental records at high latitudes are too short-term to provide sufficient historical context for these trends, so paleoclimate archives are needed to better understand the functioning of the sea ice-albedo feedback. Here we use the oxygen isotope values of wood cellulose in living and sub-fossil willow shrubs (δ18Owc) (Salix spp.) that have been radiocarbon-dated (14C) to produce a multi-millennial record of climatic change on Alaska's North Slope during the Pleistocene-Holocene transition (13,500–7500 calibrated 14C years before present; 13.5–7.5 ka). We first analyzed the spatial and temporal patterns of δ18Owc in living willows growing at upland sites and found that over the last 30 years δ18Owc values in individual growth rings correlate with local summer temperature and inter-annual variations in summer sea-ice extent. Deglacial δ18Owc values from 145 samples of subfossil willows clearly record the Allerød warm period (∼13.2 ka), the Younger Dryas cold period (12.9–11.7 ka), and the Holocene Thermal Maximum (11.7–9.0 ka). The magnitudes of isotopic changes over these rapid climate oscillations were ∼4.5‰, which is about 60% of the differences in δ18Owcbetween those willows growing during the last glacial period and today. Modeling of isotope-precipitation relationships based on Rayleigh distillation processes suggests that during the Younger Dryas these large shifts in δ18Owc values were caused by interactions between local temperature and changes in evaporative moisture sources, the latter controlled by sea ice extent in the Arctic Ocean and Bering Sea. Based on these results and on the effects that sea-ice have on climate today, we infer that ocean-derived feedbacks amplified temperature changes and enhanced precipitation in coastal regions of Arctic Alaska during warm times in the past. Today, isotope values in willows on the North Slope of Alaska are similar to those growing during the warmest times of the Pleistocene-Holocene transition, which were times of widespread permafrost thaw and striking ecological changes. Text albedo Arctic Arctic Ocean Bering Sea Bering Strait Climate change Ice north slope permafrost Sea ice Alaska The College of Wooster: Open Works Arctic Arctic Ocean Bering Sea Bering Strait Pacific |
institution |
Open Polar |
collection |
The College of Wooster: Open Works |
op_collection_id |
ftcollegewooster |
language |
unknown |
topic |
arctic Alaska paleoclimate oxygen isotopes climate change sea ice dendrochronology younger dryas North Pacific Bering Strait Geology |
spellingShingle |
arctic Alaska paleoclimate oxygen isotopes climate change sea ice dendrochronology younger dryas North Pacific Bering Strait Geology Gaglioti, Benjamin V. Mann, Daniel H. Wooller, Matthew J. Jones, Benjamin M. Wiles, Greg Groves, Pamela Younger-Dryas cooling and sea-ice feedbacks were prominent features of the Pleistocene-Holocene transition in Arctic Alaska |
topic_facet |
arctic Alaska paleoclimate oxygen isotopes climate change sea ice dendrochronology younger dryas North Pacific Bering Strait Geology |
description |
Declining sea-ice extent is currently amplifying climate warming in the Arctic. Instrumental records at high latitudes are too short-term to provide sufficient historical context for these trends, so paleoclimate archives are needed to better understand the functioning of the sea ice-albedo feedback. Here we use the oxygen isotope values of wood cellulose in living and sub-fossil willow shrubs (δ18Owc) (Salix spp.) that have been radiocarbon-dated (14C) to produce a multi-millennial record of climatic change on Alaska's North Slope during the Pleistocene-Holocene transition (13,500–7500 calibrated 14C years before present; 13.5–7.5 ka). We first analyzed the spatial and temporal patterns of δ18Owc in living willows growing at upland sites and found that over the last 30 years δ18Owc values in individual growth rings correlate with local summer temperature and inter-annual variations in summer sea-ice extent. Deglacial δ18Owc values from 145 samples of subfossil willows clearly record the Allerød warm period (∼13.2 ka), the Younger Dryas cold period (12.9–11.7 ka), and the Holocene Thermal Maximum (11.7–9.0 ka). The magnitudes of isotopic changes over these rapid climate oscillations were ∼4.5‰, which is about 60% of the differences in δ18Owcbetween those willows growing during the last glacial period and today. Modeling of isotope-precipitation relationships based on Rayleigh distillation processes suggests that during the Younger Dryas these large shifts in δ18Owc values were caused by interactions between local temperature and changes in evaporative moisture sources, the latter controlled by sea ice extent in the Arctic Ocean and Bering Sea. Based on these results and on the effects that sea-ice have on climate today, we infer that ocean-derived feedbacks amplified temperature changes and enhanced precipitation in coastal regions of Arctic Alaska during warm times in the past. Today, isotope values in willows on the North Slope of Alaska are similar to those growing during the warmest times of the Pleistocene-Holocene transition, which were times of widespread permafrost thaw and striking ecological changes. |
format |
Text |
author |
Gaglioti, Benjamin V. Mann, Daniel H. Wooller, Matthew J. Jones, Benjamin M. Wiles, Greg Groves, Pamela |
author_facet |
Gaglioti, Benjamin V. Mann, Daniel H. Wooller, Matthew J. Jones, Benjamin M. Wiles, Greg Groves, Pamela |
author_sort |
Gaglioti, Benjamin V. |
title |
Younger-Dryas cooling and sea-ice feedbacks were prominent features of the Pleistocene-Holocene transition in Arctic Alaska |
title_short |
Younger-Dryas cooling and sea-ice feedbacks were prominent features of the Pleistocene-Holocene transition in Arctic Alaska |
title_full |
Younger-Dryas cooling and sea-ice feedbacks were prominent features of the Pleistocene-Holocene transition in Arctic Alaska |
title_fullStr |
Younger-Dryas cooling and sea-ice feedbacks were prominent features of the Pleistocene-Holocene transition in Arctic Alaska |
title_full_unstemmed |
Younger-Dryas cooling and sea-ice feedbacks were prominent features of the Pleistocene-Holocene transition in Arctic Alaska |
title_sort |
younger-dryas cooling and sea-ice feedbacks were prominent features of the pleistocene-holocene transition in arctic alaska |
publisher |
Open Works |
publishDate |
2017 |
url |
https://openworks.wooster.edu/facpub/254 |
geographic |
Arctic Arctic Ocean Bering Sea Bering Strait Pacific |
geographic_facet |
Arctic Arctic Ocean Bering Sea Bering Strait Pacific |
genre |
albedo Arctic Arctic Ocean Bering Sea Bering Strait Climate change Ice north slope permafrost Sea ice Alaska |
genre_facet |
albedo Arctic Arctic Ocean Bering Sea Bering Strait Climate change Ice north slope permafrost Sea ice Alaska |
op_source |
All Faculty Articles |
op_relation |
https://openworks.wooster.edu/facpub/254 |
_version_ |
1766247768618172416 |