The tropical monsoon system encompasses the African, Indian, Australian, and East Asian Monsoons. This inter-hemispheric atmospheric phenomenon is driven by the thermal contrast between ocean and land, interacting with the global climate system through various processes. On tectonic time scales, the uplift of the Himalayas and Tibetan Plateau has been considered a significant factor in the establishment and intensification of the Indo-Australian-Asian monsoon, though its importance remains debated. Paleoclimate records suggest that monsoon evolution during the Cenozoic era was also substantially influenced by global climate changes, likely related to atmospheric CO2 levels.

On the other hand, the Indo-Pacific oceanic climate also plays a crucial role in shaping land-ocean thermal contrast and regulating water vapor circulation. This region, home to the West Pacific Warm Pool (WPWP)-the largest reservoir of oceanic heat-serves as a major source of atmospheric heat and moisture, exerting strong influence on the El Nino-Southern Oscillation (ENSO) climate pattern. The progressive constriction of the Indonesian Seaways during the Neogene has had a major impact on the formation of the WPWP and, in turn, affected ENSO dynamics. However, the precise timing and mechanisms underlying these changes are still under debate.

This session aims to assess the relative importance of these processes across different time scales, from millennial to tectonic. The goal is to advance our understanding of the evolution of the Indo-Australian-Asian Monsoon, WPWP, and ENSO variability and to explore drivers and interactions within the global climate system. Presentations based on both marine and terrestrial archives are encouraged. These studies may encompass a broad range of proxy approaches from geochemistry, geophysics, micropaleontology, sedimentology, as well as the investigation of model simulations across these realms.

The tropical monsoon system encompasses the African, Indian, Australian, and East Asian Monsoons. This inter-hemispheric atmospheric phenomenon is driven by the thermal contrast between ocean and land, interacting with the global climate system through various processes. On tectonic time scales, the uplift of the Himalayas and Tibetan Plateau has been considered a significant factor in the establishment and intensification of the Indo-Australian-Asian monsoon, though its importance remains debated. Paleoclimate records suggest that monsoon evolution during the Cenozoic era was also substantially influenced by global climate changes, likely related to atmospheric CO2 levels.

On the other hand, the Indo-Pacific oceanic climate also plays a crucial role in shaping land-ocean thermal contrast and regulating water vapor circulation. This region, home to the West Pacific Warm Pool (WPWP)-the largest reservoir of oceanic heat-serves as a major source of atmospheric heat and moisture, exerting strong influence on the El Nino-Southern Oscillation (ENSO) climate pattern. The progressive constriction of the Indonesian Seaways during the Neogene has had a major impact on the formation of the WPWP and, in turn, affected ENSO dynamics. However, the precise timing and mechanisms underlying these changes are still under debate.

This session aims to assess the relative importance of these processes across different time scales, from millennial to tectonic. The goal is to advance our understanding of the evolution of the Indo-Australian-Asian Monsoon, WPWP, and ENSO variability and to explore drivers and interactions within the global climate system. Presentations based on both marine and terrestrial archives are encouraged. These studies may encompass a broad range of proxy approaches from geochemistry, geophysics, micropaleontology, sedimentology, as well as the investigation of model simulations across these realms.