Local summer insolation and greenhouse gas forcing drove warming and glacier retreat in New Zealand during the Holocene

QUATERNARY SCIENCE REVIEWS

卷:266

Article

Dowling, Lisa^1,2  Eaves, Shaun^1,2  Norton, Kevin²  Mackintosh, Andrew³  Anderson, Brian¹  Hidy, Alan⁴  Lorrey, Andrew⁵  Vargo, Lauren¹  Ryan, Matthew²  Tims, Stephen⁶ 

[1] Victoria Univ Wellington, Antarctic Res Ctr, POB 600, Wellington 6140, New Zealand

[2] Victoria Univ Wellington, Sch Geog Environm & Earth Sci, POB 600, Wellington 6140, New Zealand

[3] Monash Univ, Sch Earth Atmosphere & Environm, Melbourne, Vic 3800, Australia

[4] Lawrence Livermore Natl Lab, Livermore, CA 94550 USA

[5] Natl Inst Water & Atmospher Res, Auckland, New Zealand

[6] Australian Natl Univ, Res Sch Phys & Engn, Dept Nucl Phys, Canberra, ACT 2601, Australia

关键词: Handling Editor: C. O'Cofaigh;    Holocene;    Glaciation;    Southern Ocean;    New Zealand;    Cosmogenic surface exposure dating;    Geomorphology;    Glacial;    Paleoclimate modeling;    Southern Hemisphere;    Little Ice Age;    Moraine chronology;   

DOI  :  10.1016/j.quascirev.2021.107068

来源: Elsevier

【 摘 要 】

Geological climate archives from the Holocene Epoch provide baseline information concerning natural climate variability. Temperate mountain glacier extent is sensitive to summer air temperature, thus geological records of past glacier length changes are a useful proxy for this climatic variable. Here we present a new cosmogenic Be-10 chronology of glacier length changes at Dart Glacier in the Southern Alps, New Zealand. Prominent moraines deposited 321 +/- 44 yr ago (n = 11) and 7.8 +/- 0.3 ka (n = 5) show glaciers during the Little Ice Age were less extensive than during the early Holocene. This pattern of net Holocene glacier retreat is consistent with emerging data from other catchments in New Zealand and across the southern mid-latitudes. Using the physical framework of a transient global climate model simulation, we suggest that cool summers in the early Holocene were promoted by the local summer insolation minimum, together with low atmospheric greenhouse gas concentrations, causing an early Holocene austral glacial maximum. An insolation-driven reduction in seasonality at southern midlatitudes may reconcile differences between early Holocene temperature reconstructions where climate proxies have different seasonal sensitivities. We suggest that rising greenhouse gas concentrations after 7 ka caused regional-scale glacier retreat and appear to be the dominant driver of multimillennial summer temperature trends in the southern mid-latitudes during the present interglacial. (C) 2021 Elsevier Ltd. All rights reserved.

【 授权许可】

Free