Report Maps the Cities Most at Risk from Water Extremes

Water is essential for a city’s growth, stability, and the well-being of its residents. It forms the foundation of a thriving society, yet both water scarcity and excess present significant threats.

Currently, 90% of natural disasters are water-related, and cities, particularly those in low-income countries, are often the most vulnerable to these events. Understanding these challenges and identifying those most at risk is crucial.

A 2025 study by WaterAid, in collaboration with researchers from Cardiff University and the University of Bristol, examined climate hazard trends and vulnerabilities across the world’s 100 most-populated cities plus 12 cities where WaterAid has worked in the last 40 years.

This report highlights that cities most severely affected by climate impacts are often those with the highest social vulnerabilities. When water, sanitation, and hygiene (WASH) systems struggle to cope with increasingly unpredictable and severe climate events, it is typically the most vulnerable and marginalised populations who bear the brunt. These impacts on health, education, and livelihoods only push them deeper into poverty.

Many communities experience a “whiplash” effect, shifting from droughts that deplete water sources to floods that overwhelm infrastructure, destroying sanitation systems and contaminating drinking water. Other cities are witnessing dramatic climate shifts, with areas once accustomed to heavy rainfall now facing droughts, while historically dry regions are now experiencing unexpected flooding.

Today, more than half of the world’s population —approximately 4.4 billion people —resides in urban areas, and this trend is expected to continue. By 2050, approximately 75% of the global population is expected to reside in urban and peri-urban areas.

With population growth and the escalating effects of climate change, decision-makers will need to grasp the increasing impacts on infrastructure and society fully. This understanding is crucial for planning and preparation, particularly in ensuring universal access to water, sanitation, and hygiene in urban areas and densely populated regions.

The report’s findings reveal that 15% of cities are experiencing a “climate whiplash,” a phenomenon where extreme dry conditions are followed by extremely wet conditions, or vice versa, are becoming significantly more frequent. These rapid shifts between extremes can be especially challenging for communities to anticipate and recover from. Cities experiencing this trend span the globe, from Asia and the Middle East to Africa and the USA.

South and Southeast Asia are emerging as regional hotspots with a significant increase in rainfall. Cities at the forefront of this trend include Colombo, Sri Lanka; Faisalabad, Pakistan; and Surat, western India. This region is experiencing an increase in wet and extremely wet conditions, which heightens the risk of severe flooding. Many of the world’s largest cities are located in this area.

In contrast, Europe, the Middle East, and North Africa, including cities such as Cairo, Amman, and Khartoum, are experiencing a drying trend, making them more susceptible to frequent and prolonged droughts.

More than 20% of cities are seeing a shift in their climate extremes. Around 13% are transitioning from arid conditions to extremely wet ones, including cities like Lucknow, Surat, and Kano, while about 7% are moving from extremely wet to dry climates, such as Cairo, Madrid, and Riyadh.

The intersection of social and infrastructure vulnerabilities with these changing climate patterns creates high-risk hotspots in two major regions: South and Southeast Asia, where wet extremes are intensifying, and North and East Africa, where both damp and dry extremes are on the rise.

In response to the accelerating trends of extreme events and shifting climate patterns, the report proposes several solutions, including harvesting rainwater to ensure a supply of clean and safe water during droughts, monitoring water levels to help communities prepare for extreme weather, and installing flood-resistant toilets to protect sanitation systems and keep water sources clean.

The report highlights that the impacts of climate change are most severe in low-income countries, where water scarcity not only presents a significant challenge but also poses a serious threat to human life.

Read the whole report by clicking the link below.