Changes in El Niño – Southern Oscillation (ENSO) conditions during the Greenland Stadial 1 (GS-1) chronozone revealed by New Zealand tree-rings

Kauri Tree‐Ring Stable Isotopes Reveal a Centennial Climate Downturn Following the Antarctic Cold Reversal in New Zealand

“…The subfossil kauri tree‐ring width and stable isotopes, in addition to climate model outputs from this study provide further evidence of spring/summer hydroclimate conditions during the YD/GS‐1 in the SH, complementing the previously constructed kauri tree‐ring width record (Palmer et al., 2016). While the millennial‐length Younger Dryas cold reversal is not strongly demonstrated in SH paleoclimate records, variability in tree‐ring 14 C (Hua et al., 2009) and the Kauri Downturn (this study and Palmer et al., 2016) imply that ocean circulation changes triggered a shorter climate deterioration lasting for at least two and a half centuries (∼12,625–12,375 cal BP) over this time interval. Such conditions are generally reflected in regional lake and ocean sediment records, albeit at lower temporal resolution.…”

“…(2009) hypothesized that the lack of uniformity between SH terrestrial (Hua et al., 2009), Pacific (Bard et al., 1998, 2004; Burr et al., 1998, 2004; Edwards et al., 1993) and Atlantic (Fairbanks et al., 2005; Hughen et al., 2004) Δ 14 C data sets during the early YD peak imply this period initiated as a result of ocean circulation changes rather than 14 C (solar) production rate. This delayed peak in tree‐ring Δ 14 C (compared to marine Δ 14 C; Hua et al., 2009) is concurrent with the KD onset (this study and Palmer et al., 2016), suggesting the ocean circulation changes may have driven this climate deterioration recorded in kauri trees on land. This theory is corroborated by the modeled incoming polar winds and related drops sea surface temperature (Figure 3).…”

“…Palmer et al. (2016) hypothesized this tree growth downturn was followed by a strengthening of ENSO expression in the region and/or solar variability. However, due to the limited climate records existing over this period and the limited age control of New Zealand records, the climatological characteristics of this centennial‐duration event remain under debate.…”

“… A high‐resolution view of the Late Glacial in the Southern Hemisphere. Decadal z ‐scored chronology (KAU‐ISO) of (a) δ 13 C cel and (b) δ 18 O cel and with standard deviation shaded ( n trees = 6); (c) tree‐ring width of full Towai chronology (Palmer et al., 2017) subsetted to length of KAU‐ISO (13,020–11,850 cal BP). Kauri Downturn (KD) shaded.…”

SHCal20 Southern Hemisphere Calibration, 0–55,000 Years cal BP

“…The kauri trees were located in Northland, at Towai (series name 8-1, CRW003) and Dargaville (series name 8-2, FIN11). The Towai decadal samples (~11,285-10,070 14 C BP) were derived from a well replicated and securely cross-matched tree-ring chronology (1451 rings, 91 radial strips derived from 37 trees with an average cross-correlation coefficient between all series of 0.71, Palmer et al 2016). The 778 analyses were determined principally by University of California, Irvine (identifier UCI, holo-cellulose, AMS), Wk (alphacellulose, high precision liquid scintillation spectroscopy) and Oxford University (identifier OxA, alpha-cellulose, AMS) with a few additional analyses by ETH (alpha-cellulose, AMS) and University of Heidelberg (identifier Hd, holo-cellulose, Gas Proportional Counting -GPC).…”