Translating Milankovitch climate forcing into eustatic fluctuations via thermal deep water expansion: a conceptual link


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Sedimentological evidence indicates metre-scale, cyclic changes in global sea-level during Mesozoic greenhouse climates; the cyclicity is thought to be due to Milankovitch forcing. The absence of continental ice-caps requires other mechanisms than glacier build-up to explain these variations. We propose that thermal expansion of the entire oceanic water column may partly explain the observed sea-level variations on Milankovitch timescales. Using existing climate model results, we show that an increase in deep water temperature of ∼ 2°C and a corresponding sea-level rise of 1.7 m by thermal expansion can be induced by Milankovitch forcing via increased formation of warm deep waters in low latitudes.