International Journal of Science, Engineering and TechnologyAuthors: Muhammad Nura, Zahrahtul Amani Zakaria
Abstract: Floods are the most common natural disaster associated with our changing climate, accounting for more than 40% of all weather-related events worldwide. Since 2000, they have affected over 1.6 billion people. As the planet warms, the global water cycle is intensifying, resulting in heavier and more frequent downpours that cover wider areas, particularly in tropical and monsoon regions. At the same time, social and economic factors such as rapid population growth, unplanned urban expansion, changes in land use, and weak local institutions have made communities more susceptible and vulnerable to floods. These issues have also led to significant differences between regions in the severity of floods and their preparedness to handle them. This paper presents a global perspective on the evolving patterns of heavy rainfall and flood risks, with a focus on variations across Asia, Africa, Europe, and North America. It also explores how natural climate patterns like El Niño and La Niña (together known as ENSO), the Indian Ocean Dipole (IOD), and the Atlantic Multidecadal Oscillation (AMO) influence flood risks over periods ranging from a few years to several decades. These natural influences make it hard to rely on the old assumption that flood patterns stay constant over time. This creates challenges when estimating design floods or predicting the frequency of extreme floods, especially in areas with limited data or highly variable weather conditions. The review also examines the implications of these changes for measuring and understanding flood risk. It emphasizes the importance of using reliable statistical methods, such as Trimmed L-moment-based Regional Frequency Analysis (RFA), to obtain more accurate results. By being less affected by outliers and allowing data to be shared across regions, these methods offer a helpful way to make estimates of extreme rainfall and flooding more reliable. This helps improve planning and supports stronger, climate-resilient flood-risk management in a changing world. This review does not introduce any new statistical methods. Instead, it synthesizes existing research to explain when and where strong regional frequency approaches are most effective in a climate that’s no longer stable or predictable.
