50+ cities unite to fight extreme heat

June 06, 2026

More than 50 cities worldwide have joined the United Nations Environment Programme’s (UNEP) new 50@50 initiative, a global effort designed to tackle one of the most rapidly escalating climate threats: extreme urban heat.

Officially launched on Heat Action Day ahead of World Environment Day, the 50@50 activation brings together city leaders to strengthen heat resilience, evaluate preparedness systems, exchange proven strategies, and accelerate actions that both safeguard communities and reduce greenhouse gas emissions driving global warming.

Cities from diverse regions—including Antalya, Lagos, Melbourne, Mendoza, Paris, and Yangzhou—are collaborating through the 50@50 platform to share practical experiences, innovative solutions, and successful approaches to heat adaptation and emergency preparedness. The initiative, developed by UNEP in partnership with the City of Paris, supports the Beat the Heat implementation campaign introduced during the UN Climate Change Conference in Belém (COP30), which aims to boost local action on extreme heat and sustainable cooling.

The 50@50 program promotes people-focused and scalable solutions such as:

• Creating cooling islands in public areas
• Expanding urban green spaces and tree cover
• Installing public drinking water fountains
• Developing community cooling centers
• Implementing heat early warning systems
• Enhancing cycling and active transport infrastructure
• Increasing shaded public spaces
• Using reflective materials and climate-responsive urban design to reduce heat absorption

“Extreme heat is already transforming everyday life in cities around the globe and is expected to reach dangerous levels under nearly every climate scenario,” said Inger Andersen, Executive Director of UNEP. “The impacts are especially severe for smallholder farmers and vulnerable populations. Through 50@50, cities can learn from one another, adopt practical solutions faster, reduce inequalities, and build stronger urban resilience.”

As global temperatures continue to rise, cities are experiencing more frequent, prolonged, and intense heatwaves. Extreme heat contributes to nearly 500,000 deaths annually and can make schools, homes, transportation systems, and public spaces unsafe during peak temperature periods. It also increases energy demand, widens social inequalities, and places additional pressure on healthcare systems, energy infrastructure, air quality, and local economies.

“Extreme heat is emerging as one of the defining challenges facing cities today,” said Emmanuel Grégoire, Mayor of Paris. “Inspired by Paris’ own 50°C heat simulation exercise, this initiative is built on the belief that cities must work together to anticipate heat risks and better protect residents. Collaboration remains our strongest tool.”

Over the next 12 months, a select group of cities will conduct comprehensive extreme heat stress tests with support from UNEP, the C40 Cities Climate Leadership Group, and the City of Paris, which has already completed a similar assessment.

Running through World Environment Day 2026 and beyond, the 50@50 initiative is creating a global network of cities committed to advancing urban heat resilience. By fostering peer-to-peer learning and encouraging proactive urban redesign, participating cities aim to move beyond simply responding to heat emergencies and instead create healthier, safer, and more climate-resilient communities.

A complete list of participating cities will be published on the World Environment Day website.