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

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, ). 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 CO2 and/or Antarctica rising temperatures.