Climate risks are emerging faster in cities than many realise, new global study finds
Research involving Prof. Felix Creutzig provides the first global assessment of how multiple climate hazards are unfolding across 11,000 cities, revealing that many urban areas are experiencing stronger climate impacts than their surrounding regions and that smaller cities face particularly acute risks.
Cities are home to more than half of the world’s population and generate most global economic activity. Yet many climate assessments focus on national or regional trends, overlooking how risks emerge in individual urban areas.
A new study published in Urban Climate by an international team of researchers provides the first global assessment of when and where multiple climate hazards become detectable across almost 11,000 cities worldwide.
Using high-resolution climate models, the researchers examined six major hazards: extreme heat, heat stress, heavy rainfall, drought, wildfire risk and coastal flooding. The findings show that climate change is already having clear impacts on cities across the globe, with heat-related hazards emerging earlier and more consistently than any other climate threat.
Heat is the defining urban climate challenge
The study finds that extreme heat has already emerged beyond historical climate variability in virtually all cities analysed. Rising temperatures, increasingly hot days and warmer nights are no longer future risks but present-day realities.
Other hazards, including heat stress, drought and wildfire-conducive conditions, are also expected to affect the vast majority of cities over the coming decades. In contrast, changes in extreme rainfall emerge later and vary more significantly between regions.
The findings suggest that urban policymakers should treat heat adaptation as an immediate priority, alongside efforts to reduce emissions.
Cities experience climate risks differently
One of the study’s most important conclusions is that cities often experience stronger climate hazards than the wider regions in which they are located.
The researchers found that risks linked to heat stress and wildfire conditions frequently intensify within urban areas, highlighting the importance of city-specific climate assessments. Relying solely on regional climate projections may underestimate the scale of challenges facing urban populations.
For policymakers, this reinforces the need for localised climate planning that reflects the specific vulnerabilities of cities rather than broader regional averages.
Emissions reductions can buy valuable time
The research also demonstrates the benefits of climate mitigation.
Under lower-emissions scenarios, the emergence of several climate hazards can be delayed by five to ten years or more. This additional time gives governments and communities greater opportunities to implement adaptation measures, improve resilience and protect vulnerable populations.
The study therefore highlights the importance of pursuing mitigation and adaptation together. Reducing emissions does not eliminate climate risks, but it can significantly slow their escalation.
Coastal flooding could deepen inequality
The researchers also examined future exposure to coastal flooding in around 1,000 coastal cities worldwide.
Without adequate protection, poorer cities are projected to face substantially greater flood exposure than wealthier urban areas, particularly in parts of Africa and Central and South America. Climate change therefore risks reinforcing existing global inequalities.
However, the study finds that investments in coastal protection can dramatically reduce these disparities. Strengthening flood defences and resilience infrastructure could significantly lower future risks, regardless of a city’s income level.
Why smaller cities need more attention
While climate discussions often focus on major metropolitan centres, the research shows that smaller and medium-sized cities may face some of the greatest challenges.
Many of these cities are expected to experience high levels of climate risk but have fewer resources to prepare for and respond to emerging hazards. The authors argue that adaptation funding and policy support should be directed not only towards megacities but also towards smaller urban areas that may be particularly vulnerable.
For governments, city leaders and international organisations, the message is simple: climate risks are no longer a future urban challenge. They are already unfolding, and effective policy must combine rapid emissions reductions with targeted investments in resilience and adaptation.
Read the paper: Global cities under multiple climate hazards
