Development of composite vulnerability index and district level mapping of climate change induced drought in Tamil Nadu, India

In India, Tamil Nadu is one of the states most vulnerable to drought impacting agriculture and allied activities. This study attempts to develop a new composite drought vulnerability index (CDVI) comprising both crop and dairy indicators for 30 districts of Tamil Nadu, India. The computation of index was based on the Intergovernmental Panel on Climate Change (IPCC) approach using exposure, sensitivity and adaptive capacity. Initially, indicators were normalized to make sure that all the indicators are comparable and weights were assigned to each indicator based on principal component analysis. Then, the districts were classified as high, moderate and less vulnerable on the basis of magnitude of the index. Coimbatore has the highest exposure to drought vulnerability (0.58) and the lowest was in Krishnagiri (0.35). In case of sensitivity, the highest was in Kancheepuram (0.69), while the lowest was in Tiruppur (0.26). The highest adaptive capacity was observed in Nagapattinam (0.52) and the lowest was in Tiruppur (0.24). None of the districts had higher adaptive capacity than sensitivity and exposure, combinedly. Overall, CDVI was highest in Kanchipuram (0.88), lowest in Erode (0.45) and moderate in Thanjavur (0.73). District level vulnerability mapping showed that twelve districts were categorized as highly vulnerable to drought; eight districts as moderately vulnerable; and ten districts as less vulnerable. Most of the districts in north eastern and southern agro-climatic zones; a few districts in Cauvery delta and western zones of Tamil Nadu had come under high vulnerable category, while a majority of the districts in north western, western and high rainfall zones were less vulnerable. To mitigate drought vulnerability, government should focus and aid in developing regional level adaptation strategies such as water conserving techniques/farm pond and appropriate policy measures to safeguard the livelihood from agriculture and dairying. Also, special attention may be given to local people’s understandings about drought including traditional practices to cope-up vulnerability.