A new study forecasts dire impact of climate-driven floods, drought to world’s major cities



CEBU CITY – A new research conducted by C40 Cities revealed that climate-related floodings and drought are expected to impact millions of people and cost world’s major cities $194 billion annually and that without urgent action, millions more people around the globe will face grave risks from river flooding, along with more frequent and severe drought by 2050.

C40 is a network of nearly 100 mayors of the world’s leading cities, currently chaired by Mayor of London Sadiq Khan; and three-term Mayor of New York City Michael Bloomberg serving as President of the Board.  The organization is working to deliver the urgent action needed right now to confront the climate crisis and create a future where everyone, everywhere can thrive.

Supported by the Grundfos Foundation, C40’s analysis, entitled “Water Safe Cities” leverages data from the network’s nearly 100 member cities to forecast the potential impacts of global temperature rise on urban economies and infrastructure.

The findings showed that if global warming continues unabated, 7.4 million people in the world’s largest cities will be exposed to severe river flooding within the next three decades, with damages to urban areas expected to cost $64 billion per year by 2050, even with current levels of global flood protections in place.


“The climate emergency is one of the biggest global threats we face today. Here in London we are already experiencing first-hand the devastating impact of the climate crisis, with flash flooding last summer impacting homes, businesses, train stations, hospitals and bringing life in parts of the capital to a halt,” Sadiq Khan, Chair of C40 Cities and Mayor of London said.


Sadiq Khan, Chair of C40 Cities and Mayor of London

Khan went on that this crisis also exacerbates social and racial injustices. The effects of the climate crisis don’t impact citizens equally. It’s the most vulnerable-particularly those in the Global South that face the worst consequences of climate change.

Poverty, deprivation and health inequalities will also reduce people’s ability to prepare for, respond to, and recover from flooding incidents.  “To address the climate emergency, mayors around the world need to create resilient cities that are adapted to the impacts of climate change including flooding.  As Chair, I’m working closely with C40 mayors to take urgent action so that our cities are safer, greener and more prosperous for all,” Khan stated.

More findings from the C40 research

C40’s research also suggests that devastating river and coastal flooding will unleash enormous economic, health, and social consequences that will affect millions across the globe.  While cities across both the Global North and Global South are going to be affected by rising sea levels, populations in the Global South are ten times more likely to be affected by flooding and drought than residents in the Global North.

Residents of Global North cities will face higher urban damage costs than residents of cities in the Global South, as many as 2,400 hospitals and healthcare facilities in C40 cities could be underwater by 2050, with nearly half of them in India, the findings read.

The research also underscores that the world’s most vulnerable populations will increasingly find themselves on the front line of the climate crisis and are forced to endure its worst impacts.

C40’s analysis showed how urgent action, such as using green solutions for water permeability and flood protection, improving water system efficiency and incorporating climate risk into urban planning can help cities to adapt to the climate emergency and work towards a climate-safe future for their residents.

Some key findings Include: River flooding is expected to cost C40 cities $136 billion in GDP each year over the next three decades.  More frequent and severe droughts will increase water losses in C40 cities by 26 percent and will cost $111 billion in damages per year over the next three decades.


Over 300 power stations across C40 cities are at risk of being flooded by 2050. More than half of the power stations affected are located in US cities. The potential loss of energy from these stations would be sufficient to power 8.4 million US homes for one year.

“Sea level rise, flooding and drought are three of the most significant climate-related risks that cities face today,” Mark Watts, Executive Director of C40 Cities noted.

Watts added that cities have a wealth of tools and knowledge at their disposal to ensure that they are adequately preparing for the realities of the climate crisis, but effective action starts with an understanding of the scope and scale of the challenge.

Commitments of C40 Cities to confront the climate-related crises

Mayors of C40 cities committed to use a science-based and people-focused approach to help the world limit global heating to 1.5°C and build healthy, equitable and resilient communities.

Through a Global Green New Deal, mayors are working alongside a broad coalition of representatives from labor, business, the youth climate movement and civil society to go further and faster than ever before.


“We are grateful to the Grundfos Foundation for supporting this critical research on climate-related water hazards, and we look forward to working together with cities in our network in the coming months and years to ensure they can effectively respond to these growing threats,” Watts said.

Following the study, C40 announced that C40 mayors will collaborate over the next several years to make and deliver upon new, ambitious commitments aimed at protecting urban populations from flooding and drought.

Phase two of the “Water Safe Cities” project, supported also by the Grundfos Foundation, will establish data-driven targets, indicators and implementation pathways to track cities’ progress in mitigating these risks.

“Grundfos’ founder, Poul Due Jensen, always said that the world is full of problems that can be solved in a better way. He also strongly believed that anyone with the skills and knowledge to make a difference in the world had an obligation to do so,” Kim Nøhr Skibsted, Executive Director of the Grundfos Foundation bared.

Skibsted bared that the organization has identified the challenges, the solutions and technologies to fix them are already available. What is needed now is to take action together. That is why the Grundfos Foundation is proud to partner with C40 Cities on the important work being done through the Climate Leadership Group, he added.

C40’s work and commitments are also supported by Bloomberg Philanthropies, Children’s Investment Fund Foundation (CIFF), and Realdania.

The Grundfos Foundation (Poul Due Jensen Foundation) is a Danish commercial foundation. Grundfos’ founder, Poul Due Jensen created the Foundation on May 19, 1975. In 2022, the Foundation pledged 250m DKK to philanthropic purposes within three strategic areas: Water, Research and Inclusion.

The Foundation has contributed US$1.6 million towards Water Safe Cities II and financed the research phase Water Safe Cities I with US$0.9 million.