The expanding Indo-Pacific freshwater pool and changing freshwater pathway in the South Indian Ocean

Chen, G., Han, W., Hu, A., Meehl, G. A., Gordon, A. L., et al. (2026). The expanding Indo-Pacific freshwater pool and changing freshwater pathway in the South Indian Ocean. Nature Climate Change, doi:https://doi.org/10.1038/s41558-025-02553-1

Title The expanding Indo-Pacific freshwater pool and changing freshwater pathway in the South Indian Ocean
Genre Article
Author(s) G. Chen, W. Han, Aixue Hu, Gerald A. Meehl, A. L. Gordon, T. Shinoda, Nan Rosenbloom, L. Zhang, Y. Masumoto
Abstract Understanding ocean freshwater variability is key to assessing the global water cycle and climate change, but changes in freshwater storage and transport remain unclear. Here we show that the South Indian Ocean—a vital conduit for interocean exchange—has experienced the strongest freshening in the Southern Hemisphere since the 1960s. This freshening drives a southward expansion of the Indo-Pacific freshwater pool into the South Indian Ocean, where freshwater has increased by 6.5 ± 0.5% per decade, as indicated by the shrinking 35.3 psu isohaline. Strengthened Indonesian Throughflow and intensified Subtropical Gyre inflow are the primary causes. In the upper ~200 m, freshening follows a new subtropical pathway rather than the usual tropical route. These changes arise from wind shifts linked to the Hadley cell's poleward expansion and a stronger Indonesian Throughflow, both driven by warm-pool warming. Ongoing warming will further expand the freshwater pool and broaden the subtropical pathway, affecting climate, interocean exchange and marine ecosystems.
Publication Title Nature Climate Change
Publication Date Mar 1, 2026
Publisher's Version of Record https://doi.org/10.1038/s41558-025-02553-1
OpenSky Citable URL https://n2t.net/ark:/85065/d7445s1m
OpenSky Listing View on OpenSky
CGD Affiliations ESP

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