650 million city residents will face water scarcity in 20501
1.6 billion city residents will face extreme heat by 20502
98 % of C40 cities have already faced severe climate threats3

About this sector

Cities, home to over half of the global population, deal with the challenges of drought, extreme heat, water scarcity, and flooding daily. These climate hazards, responsible for 90% of global disasters, are expected to intensify with the unfolding climate crisis.

Two-thirds of the world’s major cities, particularly coastal cities, face heightened vulnerability to rising sea levels, exposing millions to extreme flooding risks. By 2050, an estimated 7.4 million people in at-risk areas will face flooding. C40 data also shows that by 2025, two-thirds of the world could face water shortages, affecting 650 million people in cities by 2050.

And these impacts are disproportionate. Vulnerable communities bear the brunt; C40 cities in low and middle-income countries are ten times more likely to be affected by flooding and drought than those in high-income countries.

Mayors recognise the urgency of this crisis and are united in action to address water-related climate risks. To strengthen resilience, safeguard vulnerable populations, reduce water-related damage, and help build a safe and healthy future for residents, cities are:

  • Establishing early warning systems in all low-income areas where communities face a high risk of flooding and drought.
  • Developing emergency responses to protect all people during critical events with actions such as ensuring safe and accessible shelters and provision of basic needs.
  • Implementing cool surfaces and expanding urban tree cover to combat urban heat.
  • Improving river catchment management and implementing sustainable urban drainage systems to protect against flooding.
  • Preparing for sea level rise and coastal storms with nature-based and artificial barriers.
  • Improving water system efficiency, water treatment and recycling/reuse to ensure water security.

C40 supports cities to implement high-impact actions by providing research and technical assistance, focusing on critical gaps in water management such as data and monitoring, equitable water access, stewardship, water pricing integration, and sustainable drainage systems.

Learn more about our networks, programmes and activities below.

Networks & Programmes

  1. The Future We Don’t Want, 2018 report by C40 and GCOM.
  2. Same as above.
  3. CDP, 2019.

Contact the team