Temperature Evolution of the Indo‐Pacific Warm Pool Over the Holocene and the Last Deglaciation

Abstract

The Indo-Pacific Warm Pool (IPWP) contains the warmest surface ocean waters on our planet making it a major source of heat and moisture to the atmosphere. Changes in the extent and position of the IPWP likely impacted the tropical and global climate in the past and may also do in the future. With the aim to put recent ocean changes into a longer temporal context, we present new paleoceanographic sea surface temperature reconstructions from the heart of the Western Pacific Warm Pool, which is the warmest region within the IPWP, across the last 17,000 years. To provide an improved spatial and temporal regional context we use new and published sea surface temperature records from the IPWP and update previous compilation efforts (Linsley et al., 2010, https://doi.org/10.1038/ngeo1920). We similarly conclude that the IPWP was warmer in the early Holocene compared to the late Holocene. However, with the new data we are able to argue against a western displacement/expansion of the IPWP and suggest a warmer southern IPWP in the early Holocene. We explore the potential drivers of the Holocene IPWP cooling and propose a combination of processes including changes in the monsoonal winds associated with the position of the rain belt, the tropical Pacific mean climate, and upper water column mixing. The proposed climatic processes differentially impacted the IPWP subregions resulting in spatially diverse trends. Additionally, the late deglacial section of the records mostly show a gradual IPWP warming similar in structure to the atmospheric CO 2 and/or Antarctica rising temperatures.

Coral Record of Younger Dryas Chronozone Warmth on the Great Barrier Reef

“…The evolution of atmospheric CO 2 since the LGM is also correlated to moraine‐based late glacial warming observations (e.g., Kaplan et al, 2010; Koffman et al, 2017; Strand et al, 2019). This air temperature‐CO 2 relationship is consistent with a compilation of foraminiferal‐based SST records throughout the IPWP (South China Sea: Moffa‐Sanchez et al, 2019, Steinke et al, 2008, 2011, Sumatra: Mohtadi et al, 2014, Papua New Guinea: Moffa‐Sanchez et al, 2019, Timor Sea: Gibbons et al, 2014; Holbourn et al, 2011; Levi et al, 2007; Xu et al, 2008, and the Indonesian Throughflow: Fan et al, 2013; Linsley et al, 2010; Rosenthal et al, 2003; Schröder et al, 2016, 2018; Stott et al, 2004) (Moffa‐Sanchez et al, 2019). The coevolution of SST and CO 2 is also evident in our SSTA record when corals record near modern temperatures during the YDC and there is a coincident rise in atmospheric CO 2 commencing around 12 kyr BP (Bereiter et al, 2015) (Figure 3).…”

A new Holocene sea-level record for Singapore

“…Such oscillations may have occurred during the late-Holocene, associated with cooling of the tropical Pacific Ocean coupled with a slowdown of water exchange between the western Pacific and the South China Sea (e.g. Moffa-Sanchez et al, 2019; Partin et al, 2007). However more data is needed to decipher the possible local explanations for RSL lowstands.…”

Possible obliquity-forced warmth in southern Asia during the last glacial stage

“…Within low latitudes, most available Holocene temperature records, including SSTs and terrestrial temperatures, derive from locations outside of the Indian monsoon-influenced southern Asia [11]. These data usually show contrasting annual temperature trends at different areas, including both warming and cooling in the Indo-Pacific Warm Pool [70][71], the Indian Ocean [72][73], and tropical Africa [74]. This indicates the existence of major spatial heterogeneity in low-latitude Holocene annual temperature trend.…”

“…Notably, some local factors could override the effect of annual insolation, and induce substantial spatial heterogeneity in Holocene annual temperature trends. For instance, Holocene SST discrepancies in the Indo-Pacific Warm Pool and Indian Ocean may be attributed to monsoon-induced ocean circulation patterns [71][72], influences of northern high-latitude climates [70] and/or seasonal bias in SST proxies [73,77], while Holocene temperature changes in tropical and southern Africa have been linked to a complex interplay of local annual maximum insolation [78], tropical hydrology [79], southwestern Indian Ocean SST [80], and northern high-latitude climates [81][82]. Fortunately, model simulations suggest that our study site is in the less-complicated region where local annual insolation influences are dominant (Fig.…”