We present a near‐annually resolved record of the Indian summer monsoon (ISM) rainfall variations for the core monsoon region of India that spans from 600 to 1500 A.D. from a 230Th‐dated stalagmite oxygen isotope record from Dandak Cave. Our rainfall reconstruction, which spans the Medieval Warm Period (MWP) and the earliest portion of the Little Ice Age (LIA), indicates that the short instrumental record of ISM underestimates the magnitude of monsoon rainfall variability. Periods of severe drought, lasting decades, occurred during the 14th and mid 15th centuries and coincided with several of India's most devastating famines.

The potential of tropical speleothems as a climate proxy has been investigated. Amplitudes of 180 and 813C variations are found to be large and are likely to be primarily controlled by past rainfall. Contribution from past temperature variations seems to be relatively small. The amount effect in rainfall has been observed and quantified by analysing rainwater samples collected during a monsoon season. A tentative chronology to these speleothems is asssigned by the 14C radiometric dating method. Assuming that the variations in the 180 of cave carbonates are solely due to the past variations in rainfall, a history of the latter has been reconstructed. A high-resolution rainfall reconstruction up to the last ∼3400 years is now available from Gupteswar cave, Orissa, subject to validation of dates by the U-Th method. It is observed that in a tropical speleothem 513C is dominantly controlled by rainfall. The study has shown that tropical Indian speleothems faithfully record the annual (∼monsoon) rainfall in the cave site.

An actively growing stalagmite collected from a cave located in the hills of the Western Ghats in the Uttar Kannada District of Karnataka, India, has been studied for stable isotope ratios of oxygen and carbon, width of growth layers and grey-level changes. Distinct carbonate layers, alternate coarse and compact, are seen in cross-section. Each couplet of compact and coarse layer is found to represent a single year. A total of 331 such couplets has been counted, indicating that the stalagmite started growing in AD 1666 and continued until it was sampled. Stable isotope ratios of oxygen (δ18O) and carbon (δ13C) show variations ranging from-13.6 to-7.9%° and from-2.7 to 1.6%°, respectively. We have reconstructed past rainfall changes of the cave site using the‘amount effect’ in &δ18O of rain. Speleothemδ18O and instrumental rainfall data from the associated climate subdivision show a significant correlation (r =-0.62, decadal average). Several sharp spikes of enrichment and depletion in 18O are indicative of the past deficiency and excess in rainfall. Most of the severe drought years recorded independently by meteorological observations are found registered in the stalagmite layers. During the 331-year-period, rainfall was highest at Añ 1666 and lowest around AD 1900. The stalagmite-generated past rainfall record can serve as a reasonable proxy for testing monsoon models.

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