Mathematical Modelling of Rainfall and Water Security in Ranchi Using Prophet under Climate Change

Climate change significantly affects water availability in monsoon-dependent Ranchi, India. This study analyzes historical weather data (1979–2024) and uses the Prophet forecasting model to project monthly rainfall (PRCP) and average temperature (TAVG) through 2045. Based on regional trends, a 7% increase in monsoon rainfall and a 0.2°C/decade temperature rise is integrated. Rainfall deficits are calculated against a 100 mm/month baseline, adjusted for evaporation losses. Results show persistent non-monsoon deficits (e.g., 100 mm in December–February), with monsoon peaks rising to 268 mm by 2045. Temperature increases (0.4–0.6°C by 2045) exacerbate deficits, especially in May (31.2°C). These findings underscore the need for adaptive water management, such as enhanced storage and irrigation, to ensure water security in a warming climate.