title: Global warming and South Indian monsoon rainfall-lessons from the Mid-Miocene.
abstract: Precipitation over India is driven by the Indian monsoon. Although changes in this atmospheric circulation are caused by the differential seasonal diabatic heating of Asia and the Indo-Pacific Ocean, it is so far unknown how global warming influences the monsoon rainfalls regionally. Herein, we present a Miocene pollen flora as the first direct proxy for monsoon over southern India during the Middle Miocene Climate Optimum. To identify climatic key parameters, such as mean annual temperature, warmest month temperature, coldest month temperature, mean annual precipitation, mean precipitation during the driest month, mean precipitation during the wettest month and mean precipitation during the warmest month the Coexistence Approach is applied. Irrespective of a ~ 3-4 °C higher global temperature during the Middle Miocene Climate Optimum, the results indicate a modern-like monsoonal precipitation pattern contrasting marine proxies which point to a strong decline of Indian monsoon in the Himalaya at this time. Therefore, the strength of monsoon rainfall in tropical India appears neither to be related to global warming nor to be linked with the atmospheric conditions over the Tibetan Plateau. For the future it implies that increased global warming does not necessarily entail changes in the South Indian monsoon rainfall.
authors.affiliation: Institute for Earth Sciences, University of Graz, Heinrichstraße 26, 8010, Graz Austria.
authors.forename: Markus
authors.initials: M
authors.lastname: Reuter
authors.affiliation: Department of Geology and Palaeontology, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria.
authors.forename: Andrea K
authors.initials: AK
authors.lastname: Kern
authors.affiliation: Department of Geology and Palaeontology, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria.
authors.forename: Mathias
authors.initials: M
authors.lastname: Harzhauser
authors.affiliation: Department of Geology and Palaeontology, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kroh
authors.affiliation: Institute for Earth Sciences, University of Graz, Heinrichstraße 26, 8010, Graz Austria.
authors.forename: Werner E
authors.initials: WE
authors.lastname: Piller
keywords: Coexistence Approach; Global warming; Indian monsoon; Middle Miocene Climate Optimum; South India