The dynamics of warming during the last deglaciation in high-elevation regions of Eastern Equatorial Africa
Tropical mountain environments, such as the Rwenzori Mountains in equatorial Africa, are thought to be particularly sensitive to climate change. Ongoing warming in the Rwenzori is impacting local environments and communities through glacial retreat, fires, and flooding. Paleoclimate reconstructions...
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ftriceuniv:oai:scholarship.rice.edu:1911/112102 2023-05-15T13:44:55+02:00 The dynamics of warming during the last deglaciation in high-elevation regions of Eastern Equatorial Africa Garelick, Sloane Russell, James Richards, Adin Smith, Jamila Kelly, Meredith Anderson, Nathan Jackson, Margaret S. Doughty, Alice Nakileza, Bob Ivory, Sarah Dee, Sylvia Marshall, Charlie 2022 application/pdf https://hdl.handle.net/1911/112102 https://doi.org/10.1016/j.quascirev.2022.107416 eng eng Elsevier Garelick, Sloane, Russell, James, Richards, Adin, et al. "The dynamics of warming during the last deglaciation in high-elevation regions of Eastern Equatorial Africa." Quaternary Science Reviews, 281, (2022) Elsevier: https://doi.org/10.1016/j.quascirev.2022.107416. https://hdl.handle.net/1911/112102 https://doi.org/10.1016/j.quascirev.2022.107416 Journal article Text publisher version 2022 ftriceuniv https://doi.org/10.1016/j.quascirev.2022.107416 2022-08-09T20:54:14Z Tropical mountain environments, such as the Rwenzori Mountains in equatorial Africa, are thought to be particularly sensitive to climate change. Ongoing warming in the Rwenzori is impacting local environments and communities through glacial retreat, fires, and flooding. Paleoclimate reconstructions from elsewhere in Africa suggest considerable warming accompanied glacier retreat during the last glacial termination, from ∼21 thousand years before present (ka) through the early to mid-Holocene. Quantifying these changes has been difficult but could help to assess future impacts in the Rwenzori. Here, we present a ∼21 thousand-year (kyr) temperature reconstruction based on the relative abundance of branched glycerol dialkyl glycerol tetraethers (brGDGTs) from Lake Mahoma (2,990 m above sea level; m asl) in the Rwenzori Mountains, Uganda. Our record, paired with existing Rwenzori glacial moraine 10Be exposure ages, suggests that deglacial warming and glacial retreat began by ∼20 ka and accelerated at ∼18–18.5 ka. The timing of the onset of rapid warming matches the timing of the post-glacial rise in radiative forcing from atmospheric greenhouse gases (GHGs) from Antarctic ice cores (Brook et al., 1996; Marcott et al., 2014; Monnin et al., 2004; Schilt et al., 2010). Our temperature reconstruction registers ∼4.9 °C warming from the Last Glacial Maximum (LGM) to the late Holocene. This increase is larger than the average ∼2-4 °C warming observed in records from lower elevation sites in tropical East Africa, but similar to that observed at other high-elevation sites in this region. The increased warming at higher elevations thus confirms that the temperature lapse rate steepened during the LGM over this region. Our results also indicate ∼3 °C of warming during the mid-Holocene relative to the late Holocene. This suggests that the freezing-level height rose above Rwenzori summit elevations at that time, likely causing complete deglaciation of the Rwenzori Mountains from ∼5 to 7 ka. The mid-Holocene is thus a potential ... Article in Journal/Newspaper Antarc* Antarctic Rice University: Digital Scholarship Archive Antarctic Quaternary Science Reviews 281 107416 |
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Open Polar |
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Rice University: Digital Scholarship Archive |
op_collection_id |
ftriceuniv |
language |
English |
description |
Tropical mountain environments, such as the Rwenzori Mountains in equatorial Africa, are thought to be particularly sensitive to climate change. Ongoing warming in the Rwenzori is impacting local environments and communities through glacial retreat, fires, and flooding. Paleoclimate reconstructions from elsewhere in Africa suggest considerable warming accompanied glacier retreat during the last glacial termination, from ∼21 thousand years before present (ka) through the early to mid-Holocene. Quantifying these changes has been difficult but could help to assess future impacts in the Rwenzori. Here, we present a ∼21 thousand-year (kyr) temperature reconstruction based on the relative abundance of branched glycerol dialkyl glycerol tetraethers (brGDGTs) from Lake Mahoma (2,990 m above sea level; m asl) in the Rwenzori Mountains, Uganda. Our record, paired with existing Rwenzori glacial moraine 10Be exposure ages, suggests that deglacial warming and glacial retreat began by ∼20 ka and accelerated at ∼18–18.5 ka. The timing of the onset of rapid warming matches the timing of the post-glacial rise in radiative forcing from atmospheric greenhouse gases (GHGs) from Antarctic ice cores (Brook et al., 1996; Marcott et al., 2014; Monnin et al., 2004; Schilt et al., 2010). Our temperature reconstruction registers ∼4.9 °C warming from the Last Glacial Maximum (LGM) to the late Holocene. This increase is larger than the average ∼2-4 °C warming observed in records from lower elevation sites in tropical East Africa, but similar to that observed at other high-elevation sites in this region. The increased warming at higher elevations thus confirms that the temperature lapse rate steepened during the LGM over this region. Our results also indicate ∼3 °C of warming during the mid-Holocene relative to the late Holocene. This suggests that the freezing-level height rose above Rwenzori summit elevations at that time, likely causing complete deglaciation of the Rwenzori Mountains from ∼5 to 7 ka. The mid-Holocene is thus a potential ... |
format |
Article in Journal/Newspaper |
author |
Garelick, Sloane Russell, James Richards, Adin Smith, Jamila Kelly, Meredith Anderson, Nathan Jackson, Margaret S. Doughty, Alice Nakileza, Bob Ivory, Sarah Dee, Sylvia Marshall, Charlie |
spellingShingle |
Garelick, Sloane Russell, James Richards, Adin Smith, Jamila Kelly, Meredith Anderson, Nathan Jackson, Margaret S. Doughty, Alice Nakileza, Bob Ivory, Sarah Dee, Sylvia Marshall, Charlie The dynamics of warming during the last deglaciation in high-elevation regions of Eastern Equatorial Africa |
author_facet |
Garelick, Sloane Russell, James Richards, Adin Smith, Jamila Kelly, Meredith Anderson, Nathan Jackson, Margaret S. Doughty, Alice Nakileza, Bob Ivory, Sarah Dee, Sylvia Marshall, Charlie |
author_sort |
Garelick, Sloane |
title |
The dynamics of warming during the last deglaciation in high-elevation regions of Eastern Equatorial Africa |
title_short |
The dynamics of warming during the last deglaciation in high-elevation regions of Eastern Equatorial Africa |
title_full |
The dynamics of warming during the last deglaciation in high-elevation regions of Eastern Equatorial Africa |
title_fullStr |
The dynamics of warming during the last deglaciation in high-elevation regions of Eastern Equatorial Africa |
title_full_unstemmed |
The dynamics of warming during the last deglaciation in high-elevation regions of Eastern Equatorial Africa |
title_sort |
dynamics of warming during the last deglaciation in high-elevation regions of eastern equatorial africa |
publisher |
Elsevier |
publishDate |
2022 |
url |
https://hdl.handle.net/1911/112102 https://doi.org/10.1016/j.quascirev.2022.107416 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
Garelick, Sloane, Russell, James, Richards, Adin, et al. "The dynamics of warming during the last deglaciation in high-elevation regions of Eastern Equatorial Africa." Quaternary Science Reviews, 281, (2022) Elsevier: https://doi.org/10.1016/j.quascirev.2022.107416. https://hdl.handle.net/1911/112102 https://doi.org/10.1016/j.quascirev.2022.107416 |
op_doi |
https://doi.org/10.1016/j.quascirev.2022.107416 |
container_title |
Quaternary Science Reviews |
container_volume |
281 |
container_start_page |
107416 |
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1766208540236578816 |