What drives the Asian monsoonal circulation and rainfall?
The Asian monsoons bring significant rainfall to continental Asia and directly influence the daily life and economy of one third of the world’s population. Frequent meteorological extreme events emphasize that the monsoon is affected by recent climate change and respond to increasing atmospheric level of carbon dioxide (pCO2). The medium to longer-term effects of changes in the monsoonal system control precipitation and aridification in continental Asia and, in the past, shaped Eurasian paleoenvironments and biotic evolution. The Asian monsoons have long been thought to have originated ~23 Myr ago, driven by regional uplift. However, my previous work has shown that the monsoons are more ancient than previously thought and were possibly active with patterns similar to today during the high pCO2 Eocene Greenhouse episode. This early origin for the monsoons opens a vast array of new questions: (1) How did these early monsoons evolve through the Eocene? (2) How did they react to the numerous, short-term hyperthermal and hypothermal pCO2 events that ruled this period?
My students, collaborators, and I address these issues by focusing on different key sedimentary records in the Eocene monsoonal realm. We date stratigraphic records in Myanmar, China, and India, and investigate them with paleobotanical, geochemical, and mineralogical paleoclimatic proxies, such as pollen identification or stable and clumped isotope analyses. Our work document the short- and long-term variations of the Asian monsoons during the Cenozoic and provide the basis for a substantial advance in our understanding of monsoonal forcing factors in a warmer world.
More about this research project: They speak about it in the news here. More info are available on the website of the Myanmar Paleoclimate and Geodynamics Research Group (MyaPGR), that I founded and co-lead. The MyaPGR is currently inactive following the 2021 military coup in Myanmar.
Collaborators and (former) students: Guillaume Dupont-Nivet (University of Rennes), Carina Hoorn, Huasheng Huang & Daniel Perez-Pinedo (University of Amsterdam), Anaïs Boura, Dario de Franceschi & Nicolas Gentis (MNHN, Paris), Yannick Donnadieu, Delphine Tardif & Anta Sarr (CEREGE), Niels Meijer & Andreas Mulch (Uni Frankfurt), Mara Page (University of Michigan), Day Wa Aung, Myat Kay Thi & Hnin Hnin Swe (Uni Yangon), Zaw Win (Uni Shwebo).
Topical papers:
N. Meijer, G. Dupont-Nivet, N. Barbolini, A. Woutsen, A. Rohrmann, Y. Zhang, X.J. Liu, A. Licht, H.A. Abels, C. Hoorn, R. Tjallingii, C. Andermann, M. Dietze & N. Nowaczyk (2021). Onset of Asian dust at 40 Ma. Paleoceanography and Paleoclimatology 36 (3), e2020PA003993.
N. Barbolini, A. Woutersen, G. Dupont-Nivet, D. Silvestro, D. Tardif, P.M.C. Coster, N. Meijer, C. Chang, H.X. Zhang, A. Licht, C. Rydin, A. Koutsodendris, F. Han, A. Rohrmann, X-J. Liu, Y. Zhang, Y. Donnadieu, F. Fluteau, J-B. Ladant, G. Le Hir and C. Hoorn (2020). Cenozoic evolution of the steppe-desert biome in Central Asia. Science advances 6, eabb8227.
M. Page, A. Licht, G. Dupont-Nivet, N. Meijer, A. Schauer, K. Huntington, D. Bajnai, J. Fiebig, A. Mulch, & Z. Guo (2019). Synchronous cooling and decline in monsoonal rainfall in NE Tibet through the fall into the Oligocene Icehouse. Geology 47 (3), 203-206.
A. Licht, G. Dupont-Nivet, A. Pullen, P. Kapp, H.A. Abels, Z. Lai, Z. Guo, J. Abell & D. Giesler (2016). Resilience of the Asian atmospheric circulation shown by Paleogene dust provenance. Nature Communications 6.
A. Licht, M. van Cappelle, H. A. Abels, J.B. Ladant, J. Trabucho-Alexandre, C. France-Lanord, Y. Donnadieu, J. Vandenberghe, T. Rigaudier, C. Lécuyer, D. Terry Jr., R. Adriaens, A. Boura, Z. Guo, Aung Naing Soe, J. Quade, G. Dupont-Nivet & J.-J. Jaeger (2014). Asian monsoons in a late Eocene greenhouse world. Nature 513, 501-506.
Alexis Licht 