Holocene climate records from lake sediments in India: Assessment of coherence across climate zones

Holocene lake records constitute an important archive for the reconstruction of paleoclimate. Despite the overall climatic stability of the Holocene, the monsoons in India, both summer, and winter, show various episodes of weakening and strengthening during this time interval. As the Holocene lake records are distributed across the various geomorphic and climatic zones of India, they offer the possibility of understanding regional scale variations in terms of both qualitative and quantitative assessment of the available proxy data. The present-day precipitation in India varies from < 200 to similar to 3800 mm (IMD), and the climate changes from arid to humid generally from west to east. The compiled lake records were aggregated into eight different zones based on their climatic and geomorphic settings. Data has been compiled from 76 lake records from India and then classified as per the various geomorphic-climatic zones of the country. The multiple lake proxies indicate fluctuating lake levels throughout the Holocene and also show regional scale coherence for specific climatic events. A majority of the records witness a peak in monsoon strength between 9 and 5 kyr BP, corresponding to the globally recorded warm and wet period of the Holocene Climate Optima. After 4 kyr BP, a general trend in aridity is recorded throughout India. This assessment shows that 17 lake records have a reasonable stratigraphic resolution, and only 9 other lake records provide paleoclimate information for a duration extending more than 8 kyr. This study also emphasizes the importance of assessing the sensitivity of the lakes with respect to their geomorphic climatic settings. We suggest that several sites across the different geomorphic-climatic zones should be reoccupied to generate high fidelity records with a stronger chronological framework to strengthen the Holocene climatic reconstructions of the Indian sub-continent.