Nonlinear response of summer temperature to Holocene insolation forcing in Alaska
Regional climate responses to large-scale forcings, such as precessional changes in solar irradiation and increases in anthropogenic greenhouse gases, may be nonlinear as a result of complex interactions among earth system components. Such nonlinear behaviors constitute a major source of climate “su...
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ftpubmed:oai:pubmedcentral.nih.gov:3228435 2023-05-15T14:49:24+02:00 Nonlinear response of summer temperature to Holocene insolation forcing in Alaska Clegg, Benjamin F. Kelly, Ryan Clarke, Gina H. Walker, Ian R. Hu, Feng Sheng 2011-11-29 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3228435 http://www.ncbi.nlm.nih.gov/pubmed/22084085 https://doi.org/10.1073/pnas.1110913108 en eng National Academy of Sciences http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3228435 http://www.ncbi.nlm.nih.gov/pubmed/22084085 http://dx.doi.org/10.1073/pnas.1110913108 Biological Sciences Text 2011 ftpubmed https://doi.org/10.1073/pnas.1110913108 2013-09-03T23:21:02Z Regional climate responses to large-scale forcings, such as precessional changes in solar irradiation and increases in anthropogenic greenhouse gases, may be nonlinear as a result of complex interactions among earth system components. Such nonlinear behaviors constitute a major source of climate “surprises” with important socioeconomic and ecological implications. Paleorecords are key for elucidating patterns and mechanisms of nonlinear responses to radiative forcing, but their utility has been greatly limited by the paucity of quantitative temperature reconstructions. Here we present Holocene July temperature reconstructions on the basis of midge analysis of sediment cores from three Alaskan lakes. Results show that summer temperatures during 10,000–5,500 calibrated years (cal) B.P. were generally lower than modern and that peak summer temperatures around 5,000 were followed by a decreasing trend toward the present. These patterns stand in stark contrast with the trend of precessional insolation, which decreased by ∼10% from 10,000 y ago to the present. Cool summers before 5,500 cal B.P. coincided with extensive summer ice cover in the western Arctic Ocean, persistence of a positive phase of the Arctic Oscillation, predominantly La Niña-like conditions, and variation in the position of the Alaskan treeline. These results illustrate nonlinear responses of summer temperatures to Holocene insolation radiative forcing in the Alaskan sub-Arctic, possibly because of state changes in the Arctic Oscillation and El Niño-Southern Oscillation and associated land–atmosphere–ocean feedbacks. Text Arctic Arctic Ocean Alaska PubMed Central (PMC) Arctic Arctic Ocean Proceedings of the National Academy of Sciences 108 48 19299 19304 |
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Biological Sciences Clegg, Benjamin F. Kelly, Ryan Clarke, Gina H. Walker, Ian R. Hu, Feng Sheng Nonlinear response of summer temperature to Holocene insolation forcing in Alaska |
topic_facet |
Biological Sciences |
description |
Regional climate responses to large-scale forcings, such as precessional changes in solar irradiation and increases in anthropogenic greenhouse gases, may be nonlinear as a result of complex interactions among earth system components. Such nonlinear behaviors constitute a major source of climate “surprises” with important socioeconomic and ecological implications. Paleorecords are key for elucidating patterns and mechanisms of nonlinear responses to radiative forcing, but their utility has been greatly limited by the paucity of quantitative temperature reconstructions. Here we present Holocene July temperature reconstructions on the basis of midge analysis of sediment cores from three Alaskan lakes. Results show that summer temperatures during 10,000–5,500 calibrated years (cal) B.P. were generally lower than modern and that peak summer temperatures around 5,000 were followed by a decreasing trend toward the present. These patterns stand in stark contrast with the trend of precessional insolation, which decreased by ∼10% from 10,000 y ago to the present. Cool summers before 5,500 cal B.P. coincided with extensive summer ice cover in the western Arctic Ocean, persistence of a positive phase of the Arctic Oscillation, predominantly La Niña-like conditions, and variation in the position of the Alaskan treeline. These results illustrate nonlinear responses of summer temperatures to Holocene insolation radiative forcing in the Alaskan sub-Arctic, possibly because of state changes in the Arctic Oscillation and El Niño-Southern Oscillation and associated land–atmosphere–ocean feedbacks. |
format |
Text |
author |
Clegg, Benjamin F. Kelly, Ryan Clarke, Gina H. Walker, Ian R. Hu, Feng Sheng |
author_facet |
Clegg, Benjamin F. Kelly, Ryan Clarke, Gina H. Walker, Ian R. Hu, Feng Sheng |
author_sort |
Clegg, Benjamin F. |
title |
Nonlinear response of summer temperature to Holocene insolation forcing in Alaska |
title_short |
Nonlinear response of summer temperature to Holocene insolation forcing in Alaska |
title_full |
Nonlinear response of summer temperature to Holocene insolation forcing in Alaska |
title_fullStr |
Nonlinear response of summer temperature to Holocene insolation forcing in Alaska |
title_full_unstemmed |
Nonlinear response of summer temperature to Holocene insolation forcing in Alaska |
title_sort |
nonlinear response of summer temperature to holocene insolation forcing in alaska |
publisher |
National Academy of Sciences |
publishDate |
2011 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3228435 http://www.ncbi.nlm.nih.gov/pubmed/22084085 https://doi.org/10.1073/pnas.1110913108 |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Alaska |
genre_facet |
Arctic Arctic Ocean Alaska |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3228435 http://www.ncbi.nlm.nih.gov/pubmed/22084085 http://dx.doi.org/10.1073/pnas.1110913108 |
op_doi |
https://doi.org/10.1073/pnas.1110913108 |
container_title |
Proceedings of the National Academy of Sciences |
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108 |
container_issue |
48 |
container_start_page |
19299 |
op_container_end_page |
19304 |
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1766320450669903872 |