Joint behaviour of climate extremes across India: Past and future

Climate change significantly influences the global hydrological cycle and consequently affects climatic extremes. Therefore, the present study focuses upon the varying patterns of climate extremes across India for past and future. Here, a comprehensive methodological framework incorporating univariate and joint probabilistic analysis (using copulas) has been proposed to study the climate extremes. Moreover, multi-model ensembles of climate extreme indices are developed using reliability ensemble averaging (REA) technique for reducing uncertainty in projecting future climate extremes. The datasets used are daily precipitation, maximum temperature and minimum temperature for past (1975-2019), and future (2025-2095) under RCP4.5 and RCP8.5 scenario. A preliminary assessment of climate extremes indicates that R20, R95p, consecutive wet days (CWD), TXx, TNx, TX90p, TN90p, TNn and TXn show a positive trend predominantly across India in future. The bivariate assessment of precipitation extreme indices for the period (1989-2019) suggests that parts of north-western, north-eastern, southern, western region and Western Ghats are highly prone to floods and a large portion of country is vulnerable towards co-occurrence of floods and droughts. Moreover, integrated assessment of extreme number of hot days (TX90p) and nights (TN90p) indicate that along with the projected increase in hot days/nights, the frequency of their concurrence in a year is likely to increase in future over the country. The present study provides useful information on the regional distribution of climate extremes and can further contribute to facilitate an effective adaptation strategy.