A quantitative assessment of vulnerability of farming communities to extreme precipitation events in Lower Vellar River sub-basin, India

Increased occurrences of climate extremes are one of the primary indicators to identify climate change. From agricultural perspectives, vulnerability is the proneness of a region to extreme climate events which cause crop loss, yield reduction eventually leading to the decline in farmers income. An extreme weather event becomes a disaster when the society or ecosystems are unable to cope with it effectively. The vulnerability of agriculture in the Lower Vellar River sub-basin has been quantitatively assessed which can help provide guidelines to improve the adaptive capacities of the farming communities in the sub-basin. The vulnerability has been assessed with a total of 36 indicators categorised under three dimensions, namely sensitivity, exposure, and adaptive capacities, for the years, 2011 and 2015 which experienced extreme precipitation events, Cyclone Thane and the Deep Depression of Bay of Bengal, respectively. The vulnerability index results highlight that the sensitivity of coastal blocks, namely Parangipettai, Keerapalayam, and Mel Bhuvanagiri to precipitation extremes is higher when compared to the interior blocks Nallur, Mangalur, and Virudhachalam. The exposure of the coastal blocks to the extreme events in the years 2015 and 2011 was high, with the year 2011 having lower exposure values than 2015. The main cause for low exposure values in 2011 for the coastal blocks can be attributed to high temperature trends and subsequent high exposure index values in Mangalur which is an interior block in the basin. The adaptive capacities in the coastal blocks are very less making them highly vulnerable. In general, the coastal regions have medium–high vulnerability than the interior regions which have low-medium to medium vulnerability.