Historical Climate Records
To put the contemporary climate change in perspective, historical, documentary evidences are very useful. Such evidences, however, are generally found scattered in many places and languages with different interpretations. Sometimes, the information is vague and fragmentary. Therefore, to extract valuable information on past climate, a systematic and logical approach is crucial in interpreting historical evidences. Relative to other parts of Asia, historical records in India and China are relatively longer. They provide informative evidences of past climate. In India, historical climate evidences are mostly related to monsoonal rain, for example, occurrence of drought or flood and no harvest due to lack of rain or good grain production. A systematic effort was made by Pant et al. (1993) to extract climate-related information, such as droughts and floods leading to famine, for the last millennium from historical records of various climatic zones of India (Fig. 3a). Relatively, fewer droughts were observed during CE 900-1600 due to non-availability of related historical information. Since CE 1600, droughts are more frequent and are more or less randomly distributed (Fig. 3b).