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Through stable oxygen and carbon analyses of rapidly accumulating sediment cores from the eastern Arabian Sea, we show that the excess of evaporation over precipitation (E-P) steadily appears to have decreased during the last similar to 10 000 to similar to 2000 years, most probably due to an increasing trend in the summer monsoon rainfall, contrary to the land-based paleoclimatic data from this region, which indicate onset of aridity around 4000 years ago. Our results are consistent with the hypothesis that significant spatial variability in the monsoon rainfall observed today was persistent during most of the Holocene. Alternatively, the trend can be seen as an adjustment between two phases, one between similar to 10 000 and similar to 6000 years ago of increasing precipitation and another between 3500 and 2000 years ago after the arid episode. We also report a significant similar to 700 year periodicity, similar to that reported recently from the South China Sea, indicating that the centennial/millennial scale response of the Indian and Chinese monsoons to high latitude forcing may be alike. (C) 2000 Published by Elsevier Science B.V. All rights reserved.