Abstract
Sustainable Development Goal 13 emphasized the demand for climate action, which is crucial for understanding climatic variability and its consequences on agricultural planning as well as water resource management. The present study analyzed the trend, frequency, and magnitude of rainfall, temperature, and their extreme climate events using daily time series data for 42 years (1982-2023) with a special focus on coastal climate change in the West Bengal coast. The Mann-Kendall and descriptive statistics, Sequential Mann-Kendall, Innovative Trend, and 21 extreme climate indices have been measured. The results reveal a statistically significant decreasing trend of maximum temperature at the stations Contai and Diamond Harbour, whereas, an increasing trend at Digha and Sagar Island. The minimum temperatures with rising trends have been detected for all the stations. A statistically significant upward trend in rainfall has been observed in this area. The seasonal analysis indicates a notable increase in rainfall trends across all seasons within the region. Surprisingly, post-monsoonal rainfall increases with greater magnitude at all stations and exceeds the magnitude of monsoon rainfall, leading to a shifting of the rainfall pattern. Alterations in rainfall patterns negatively impact both the environment and the economy, leading to an increased likelihood of flooding during the post-monsoon season. This situation can adversely affect agricultural output and may give rise to concerns regarding food security. The Sequential Mann-Kendall test measured significant multiple change points of annual rainfall. The number of Consecutive Wet Days (CWD) in this area has been increasing, potentially affecting the hydrology of groundwater recharge. A prolonged series of wet days allows for greater rainwater absorption into the soil, thereby improving the replenishment of groundwater resources. The area may have experienced storm surge and extreme coastal flood due to increasing RX1 days and RX5 days. These results will enhance the understanding of the seasonal and annual water budget, which is essential for agricultural planning and the overall well-being of the region.