The 100 most populated cities in the world are becoming increasingly exposed to floods and droughts, risking the security and survival of their communities, according to a new report.
The research, developed by WaterAid with academics from Cardiff University and the University of Bristol, exposes how cities across Africa and Asia are emerging as the most at-risk to extreme climate shifts worldwide.
These shifts bring devastating impacts on access to clean water for urban communities on the frontline of climate change, the authors say.
The pioneering new study compares each city's social and water infrastructure vulnerabilities alongside 40+ years-worth of new 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.
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.
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 localized climate hazards can support more intelligent and bespoke planning in major cities.
Almost 1 in 5 (17%) of the cities studied emerge as experiencing 'climate whiplash' – the intensification of both droughts and floods – and 20% of cities have seen a major flip from one extreme to the other.
The report shows how 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.
All European cities analysed exhibit drying trends over the last 42 years, including Madrid, Paris and London – which could lead to the region facing more frequent and long-lasting droughts.
Madrid and Barcelona both show 'climate hazard flips', with Madrid ranking second on the list of cities experiencing a flip to extreme dry conditions.
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 climate change in urban centres.
WaterAid is working with partners globally to make sure people have the water they need to adapt to the impacts of climate change – including in some urban and peri-urban settings.
The solutions include 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.
Tim Wainwright, WaterAid UK's Chief Executive, said: "This research comes at a pivotal time, as we're seeing a sweep of global aid cuts, which could leave basic human rights hanging in the balance.
"It highlights the devastating shifts in extreme climate patterns across all continents, with the impact felt most clearly on low-income countries, where the absence of water becomes not just a challenge, but a matter of life and death."
Floods and droughts are stripping away people's foundation of survival - water. But with a reliable supply of clean water, communities can recover from disasters, stay healthy, and be ready for whatever the future holds. It all starts with clean water.
The report, ' Water and Climate: Rising Risks for Urban Populations ' report, is published by WaterAid.
