Western Pacific hydroclimate linked to global climate variability over the past two millennia

Abstract

Interdecadal modes of tropical Pacific ocean-atmosphere circulation have a strong influence on global temperature, yet the extent to which these phenomena influence global climate on multicentury timescales is still poorly known. Here we present a 2,000-year, multiproxy reconstruction of western Pacific hydroclimate from two speleothem records for southeastern Indonesia. The composite record shows pronounced shifts in monsoon rainfall that are antiphased with precipitation records for East Asia and the central-eastern equatorial Pacific. These meridional and zonal patterns are best explained by a poleward expansion of the Australasian Intertropical Convergence Zone and weakening of the Pacific Walker circulation (PWC) between ∼1000 and 1500 CE Conversely, an equatorward contraction of the Intertropical Convergence Zone and strengthened PWC occurred between ∼1500 and 1900 CE. Our findings, together with climate model simulations, highlight the likelihood that century-scale variations in tropical Pacific climate modes can significantly modulate radiatively forced shifts in global temperature.

Was the Little Ice Age more or less El Niño-like than the Medieval Climate Anomaly? Evidence from hydrological and temperature proxy data

“…A southward shift is analogous to an El Niño-like state (Deser and Wallace, 1990;Haug et al, 2001;Ivanochko et al, 2005), suggesting that the MCA was characterised by a La Niña-like climate state and the LIA by an El Niño-like state. However, recent studies hint at an expansion and contraction of the ITCZ in the West Pacific during the MCA and LIA respectively (Yan et al, 2015;Griffiths et al, 2016), accompanied by a respective weakening and strengthening of the Pacific Walker Circulation (PWC). El Niño is characterised by a weakening in the PWC, which would imply a La Niña-like state during the LIA.…”

Coral‐Derived Western Pacific Tropical Sea Surface Temperatures During the Last Millennium

“…However, signals from lake sediments in the eastern Pacific indicate a warm period that is more closely related to El Niño‐dominated conditions during the MCA period (Fletcher & Moreno, ; Ledru et al, ; Yan et al, ). Furthermore, speleothem records from Indonesia clearly show an El Niño‐dominated MCA, related to a weakening of the Pacific Walker circulation and a dry condition (Griffiths et al, ).…”

Hydroclimate of the Last Glacial Maximum and deglaciation in southern Australia's arid margin interpreted from speleothem records (23–15 ka)

“…The construction of highly resolved (sub-decadal) climatically sensitive geochemical records spanning 10 3 -10 4 -year timescales has also been achieved (e.g. Wang et al, 2001;Griffiths et al, 2016). For example, over glacial-interglacial transitions in monsoonal climates, they have been particularly successful in revealing the timing and structure of ice age terminations (Cheng et al, 2010) and have placed speleothems at the forefront of chosen tools for paleoclimate reconstruction (Henderson, 2006;Fairchild and Baker, 2012).…”