B. N. Goswami
B. N. Goswami is a Climate Scientist specialising in Variability and Predictability of Climate in general and Indian summer monsoon in particular and the role of Ocean-Atmosphere interactions in climate variability and predictability. His stewardship from 2006 to 2014 transformed the Indian Institute of Tropical Meteorology (IITM), Pune, to a leading Centre of Excellence in Climate Science. He is well known for his discovery of the Indian Ocean Dipole mode and quantifying the increasing trend of ‘extreme rainfall events’ over the Indian region. Leading the Indian Monsoon Mission of the Ministry of Earth Sciences (MoES) from IITM, Pune, he elevated the Indian Weather and Climate prediction capability to a level comparable to the best in the world. He received many Awards and Honors including the Shanti Swaroop Bhatnagar Award in 1995. He is Fellow of all three leading National Science Academies of India. He is also a Fellow of the World Academy of Science (TWAS).
A New Perspective on Asian Summer Monsoon evolution in the Cenozoic era
The Asian summer monsoon (ASM) is one of the most complex and dynamic climate systems (Webster et al. 1998; Wang et al. 2006), profoundly influencing more than one-third of the world’s population (Wang 2006) and supporting rich regional biodiversity (He et al. 2022; Spicer et al. 2025). The evolution of the Asian Summer Monsoon (ASM) remains uncertain (Sun and Wang 2005; Liu et al. 2017; Tardif 2020) despite its fundamental role in shaping regional climate (Ummenhofer et al. 2013; Buckley et al. 2014), ecosystems (Quade et al. 1989; Yu et al. 2014), and civilizations (Kathayat et al. 2017). Using a series of time slice simulations with the HadCM3BL climate model, we assess how India-Eurasia collision tectonics (Rowley, 1996; Najman et al., 2010), Tibetan Plateau (TP) uplift (Wang et al. 2014; Spicer et al. 2021), and CO₂ variability (Zachos et al. 2008) influenced ASM development through the Cenozoic. Our results show that ASM intensification was contingent on the TP surpassing a critical mean elevation (~3.5 km) in the late Eocene–Oligocene, which strengthened the upper-tropospheric temperature gradient, drove the northward shift of the Intertropical Convergence Zone (ITCZ), and restructured atmospheric circulation. Initially confined to East Asia (Farnsworth et al., 2019), monsoonal rainfall expanded across South Asia by the Oligocene, alongside enhanced circulation and a reversal in the meridional relative sea surface temperature gradient. While TP uplift was the primary driver of early ASM evolution, declining atmospheric CO₂ levels became increasingly influential from the late Miocene onward. Our findings, supported by sedimentary records of weathering and erosion (Clift 2006; Clift et al. 2008), underscore the TP’s dominant role in climate-tectonic interactions and ASM evolution over geological timescales.
