GLOBAL CITIES MOST VULNERABLE TO EXTREME CLIMATE SHIFTS REVEALED IN NEW WATERAID REPORT

 

PRESS RELEASE

For Immediate Release

 

GLOBAL CITIES MOST VULNERABLE TO EXTREME CLIMATE SHIFTS REVEALED IN NEW WATERAID REPORT

 Download photos from city case studies here  

• WaterAid study of the 100 most populated cities unveils dramatic shifts in flooding and droughts posing a risk for urban populations and preventing communities accessing clean water worldwide
• WaterAid report reveals regional wetting hotspot in Southern Asian cities, widespread drying throughout European cities, and ‘climate whiplash’ trends across four continents including Africa
• WaterAid working on solutions for global communities on the climate frontline, but ‘can’t do it alone’ – the organisation calls on global governments, multilateral banks and the private sector to work together to unlock investment and implement solutions to tackle the climate and water crises.

 

As Australia grapples with the aftermath of Ex-Tropical Cyclone Alfred, WaterAid has released new data revealing the escalating global crisis of water-related disasters. From intensifying droughts to catastrophic flooding, urban populations worldwide face mounting threats to clean water access.

 

New WaterAid research, published today (12 March 2025), reveals which of the world’s 100 most populated cities are becoming increasingly exposed to floods and droughts – risking the security and survival of communities around the world.

The report ‘Water and Climate: Rising Risks for Urban Populations’ unveils which cities across Africa and Asia are emerging as the most at-risk to extreme climate shifts worldwide, which is having devastating impacts on access to clean water for urban communities on the frontline of climate change.

Almost 1 in 5 (17%) of cities studied emerge as experiencing ‘climate whiplash’ – which involves intensification of both droughts and floods - whereas 20% of cities have seen a major flip from one extreme to the other. Cities in Southern Asia are becoming overwhelmingly flood-prone and European cities are exhibiting significant drying trends, all of which can impact people’s clean water access and water security.

 

Figure 3. Trends in wetting and drying over the 112 cities. The more intense the colour (blue or red) is, the stronger the trend in either wetting or drying respectively.
From recent drought in cities like Madrid (Spain) and Cape Town (South Africa), to large-scale flooding across cities in Bangladesh and Pakistan, 90% of all climate disasters are driven by too little or too much water. WaterAid, the world’s leading water, sanitation and hygiene charity, warns that weather-related disasters such as flooding and drought have increased by 400% in last 50 years, putting major pressure on vital water access and sanitation systems and making it harder for communities and economies to prepare for, recover from and adapt to climate change.

The pioneering new study, developed with academics from University of Bristol and Cardiff University, compares each city’s social and water infrastructure vulnerabilities alongside 40+ years-worth of data on climate hazards – concluding which cities and communities worldwide are the most vulnerable to extreme climate changes and the least equipped to handle them.

 

And it is not just highly populated cities facing the extremes of climate change. The Pacific Islands are some of the least responsible yet most affected when it comes to climate change.

 

Collectively, The Pacific Islands account for less than 0.03% of global greenhouse gas emissions, yet they are among the most vulnerable to the impacts of climate change. 

 

Coastal erosion, saltwater intrusion into freshwater supplies and more frequent and severe cyclones threaten homes, health and futures.

 

Rising sea levels are contaminating water sources with saltwater, rendering traditional sanitation systems ineffective. 

 

Flooding and extreme rainfall events overwhelm toilets, causing contamination of communities' water supplies and spreading diseases like cholera and diarrhoea. 

 

 

The vulnerabilities the report examines range from poverty to poor water and waste systems – exposing ever-expanding urban populations at risk to intensifying floods or droughts, leading to displacement, instability and loss of life. Severe urban flooding can damage sanitation facilities, spreading diseases such as cholera and typhoid, whilst water shortages during droughts are leaving millions of families without the water they need to survive.

 

Figure 1. Example of a flip to drier extremes (Cairo) and a flip to wet extremes (Faisalabad).

 

Top report findings include:

 

• 20% of the cities studied are experiencing dramatic shifts to extreme wet or extreme dry conditions, referred to as ‘climate hazard flips.’  Approximately 13% are flipping toward a more extreme wet climate, while about 7% are flipping toward a more extreme dry climate. This amounts to over a quarter of a billion people across the world experiencing a major flip in their climate, including in cities such as Kano (Nigeria), Bogota (Colombia) and Cairo (Egypt), placing major pressure on access to safe and clean water

 

• South and Southeast Asia emerges as a regional hotspot, with Colombo (Sri Lanka), Faisalabad (Pakistan), and Lahore (Pakistan) seeing the most dramatic flip from historically dry conditions to becoming severely flood prone

 

• 17 cities across multiple continents – 15% of the cities studied – are experiencing an intensification of both extreme floods and droughts, known as ‘climate whiplash’, including Addis Ababa (Ethiopia), Hangzhou (China), and Jakarta (Indonesia).

 

• By looking at social and infrastructural vulnerability alongside the climate data, the report, with hotspots of heightened risk in two key regions: south and southeast Asia, and north and east Africa
  
  
• The cities identified as the most vulnerable include Khartoum (Sudan), Faisalabad and Lahore (Pakistan), Baghdad (Iraq), Surabaya (Indonesia), Nairobi (Kenya), and Addis Ababa (Ethiopia)

 

• Meanwhile in Europe, the data shows cities like Madrid and Paris exhibiting significant drying trends, with Europe’s older infrastructure also putting many cities at increased risk of vulnerability to extreme weather, the new data reveals.
    

Figure 2: Critical cities that rank highly both for climate hazard trends and vulnerability (based on the average of social and infrastructural vulnerability scores). The graph presents the top 20 cities with a high-risk ranking (combining vulnerability and climate hazard) for cities experiencing a wetting (blue) and drying (red).

Tom Muller, WaterAid Australia’s Chief Executive, said:

“With 90% of all climate disasters driven by too little or too much water, there is an urgent need for governments around the world to recognise the importance of investing in long-term plans to manage water resources and guarantee access to drinking water.”

 

Unfortunately, this research comes at an incredibly pivotal time, as globally we are seeing sweeping cuts to overseas aid which undermines our collective ability to respond to the impacts of climate change.

Highlighting an increase in climate whiplash across global cities - with the impact felt most clearly in low-income countries, but with global implications – the report is a reminder that now more than ever, Australia needs to continue to be at the forefront of global efforts to address climate change.”

 

WaterAid is working with partners globally to make sure people have the water they need to adapt to the impacts of our changing climate – including in some urban and peri-urban settings. The solutions can be simple: harvesting rainwater to provide clean and safe water through drought; monitoring water levels so communities can prepare for extreme weather; installing toilets designed to withstand floods and keep water sources clean.  

But the organisation warns it is not the role of civil society alone to solve these issues and is calling on global decision makers to prioritise and invest in these key solutions that strengthen community resilience against extreme weather— to protect livelihoods, save lives, and strengthen global security in a turbulent world.

Tom Muller, WaterAid Australia’s Chief Executive, added:

“Now is the time for urgent collective action from global leaders, multilateral banks and the private sector to unlock investment so that communities can recover from disasters, stay healthy, and be ready for whatever the future holds. This will make the world a safer place for all.  It all starts with clean water.”

WaterAid is calling for:

• Greater investment to tackle the water crisis – Development partners, multilateral banks and the private sector should work together to unlock investment in climate-resilient water, sanitation and hygiene systems that benefits the most vulnerable.

• Global leadership to accelerate action on water – Governments and development partners must work through the existing multilateral platforms to deliver ambitious action on climate and water, including through the UNFCCC, the G7 Water Coalition and the G20 Call to Action on Strengthening Drinking-water, Sanitation, and Hygiene Services.

 

• National government leadership to urgently deliver water plans – Governments in affected countries to mainstream and implement water, sanitation and hygiene measures into their national and city-level climate adaptation plans with a focus on vulnerable groups, especially women and girls.

 

• Prioritise the most vulnerable communities - All decision-makers to recognise overlapping vulnerabilities and prioritise the leadership and needs of women, girls and marginalised groups in climate-resilient water, sanitation, and hygiene plans.
  
  

Professor Katerina Michaelides, Lead Scientist from University of Bristol, said:

“The findings from our study illustrate just how differently and dramatically climate change is expressing around the globe – there is no one-size-fits-all. Places that were historically wet are becoming dry and vice versa. Other places are now increasingly battered by both extreme floods and droughts. A deeper understanding of localised climate hazards and the changing global water cycle can support more intelligent and bespoke planning in major cities.”

Professor Michael Singer, Lead Scientist from Cardiff University, added:  

“One interesting outcome of this study is how many of the climate hazard trends appear to spread over broad regions, suggesting that there may be significant adaptation challenges to new hazard regimes, but also regional opportunities for collaboration between nations to become more resilient to the climate and water crisis in urban centres.”

-ENDS -

 

 

Notes to editors  

‘Water and Climate: Rising Risks for Urban Populations’: Find full report here, including full findings, data visuals and methodology.

Download photos from city case studies here

• Commissioned by WaterAid and carried out by academics from the Universities of Bristol and Cardiff, the ‘Water and Climate: Rising Risks for Urban Populations’ report, published today (12 March 2025), uncovers the change in climate hazards over the last 42 years for over 100 cities globally ranked by population size.
• Combining climate hazard trends with a new city-scale ‘urban vulnerability’ to floods and droughts for each city across social and infrastructure measures, the report unveils which cities worldwide rank as the most at-risk to climate impacts. 
• This report examines extreme shifts in wetting and drying patterns by analysing the global water cycle—changes in rainfall supply and evaporative demand. These shifts are reflected in droughts and floods rather than climate disasters like wildfires and hurricanes.

 

 

Key Facts:

• 703 million people in the world – almost one in ten – don’t have clean water close to home.[1]
• 2.2 billion people in the world – more than one in four – don’t have safe water.[2]
• 1.5 billion people in the world – almost one in five – don’t have a decent toilet of their own.[3]
• Almost 400,000 children under five die every year due to diseases caused by unsafe water, sanitation and hygiene. That's more than 1000 children a day, or almost one child every one and a half minutes.[4]
• Investing in safely managed water, sanitation and hygiene services provides up to 21 times more value than it costs.[5]

 

 

About us:

WaterAid

WaterAid is an international not-for-profit determined to make clean water, decent toilets and good hygiene normal for everyone, everywhere within a generation. We work alongside communities in 22 countries to secure these three essentials that transform people’s lives. Since 1981, WaterAid UK and its Country Programmes have reached 29 million people with clean water and 29 million people with decent toilets.

To find out more visit www.wateraid.org.au  follow @wateraidaustralia on Instagram or find WaterAid Australia on Facebook at www.facebook.com/wateraidaustralia

Contact details:

Our spokespeople are available for interview.

To book in interviews or for any media queries, please contact:

Tegan Dunne, WaterAid Australia Public Relations and Communications Manager

Ph: 0415 714 589

E: tegan.dunne@wateraid.org.au