The PALMOD 130k marine palaeoclimate data synthesis version 2

Abstract. Palaeoclimate data hold the unique promise of providing a long-term perspective on climate change and as such can serve as an important benchmark for climate models. However, palaeoclimate data have generally been archived with insufficient standardisation and metadata to allow for transparent and consistent uncertainty assessment in an automated way. Thanks to improved computation capacity, transient palaeoclimate simulations are now possible, calling for data products containing multi-parameter time series rather than information on a single parameter for a single time slice. To confront transient simulations that span the last glacial-interglacial cycle with palaeoclimate data, we have compiled a multi-parameter marine palaeoclimate data synthesis that contains time series spanning 0 to 130,000 years ago. In 2020 Jonkers et al. (2020) published the first version of the PALMOD 130k marine palaeoclimate data synthesis and described our data synthesis strategy and the contents and format of the data product in detail. Here we present a major update of the data product that markedly increases both the spatial and temporal coverage. Version 2 of the synthesis contains 2,286 time series of eight palaeoclimate parameters from 475 individual sites, each associated with rich metadata, age–depth model ensembles, and information to refine and update the chronologies. Version 2 contains 468 time series of benthic foraminifera δ¹⁸O; 357 of benthic foraminifera δ¹³C; 423 of near sea surface temperature; 482 and 273 of planktonic foraminifera δ¹⁸O and δ¹³C; and 128, 111 and 44 of carbonate, organic carbon and biogenic silica content, respectively. Compared to version 1, all radiocarbon ages have been recalibrated and the age-depth models updated. In addition, near sea surface temperature estimates based on planktonic foraminifera Mg/Ca and on UK37' have been recalculated using a single calibration thus ensuring global comparability and comprehensive assessment of their uncertainty. The data product is available in two formats (R and LiPD) facilitating use across different software and operating systems and can be downloaded at https://doi.pangaea.de/10.1594/PANGAEA.984602 (Jonkers et al., 2025b). This data descriptor presents our updating methodology and describes the contents and format of the data product in detail and concludes with recommendations on palaeodata stewardship to increase the reusability of such data.