Global Urban GHG Summit Unites Science and Policy to Drive City Climate Action

Geneva Hosts Landmark Urban Greenhouse Gas Conference to Strengthen City-Level Climate Action.

From April 7 to 9, 2025, the World Meteorological Organization (WMO) headquarters in Geneva became the global hub for advancing greenhouse gas (GHG) mitigation strategies in urban environments. The occasion marked one of the most significant international gatherings focused on greenhouse gas monitoring and reduction in cities: the Urban Greenhouse Gas Conference and Stakeholder Summit 2025.

Jointly hosted by the Integrated Global Greenhouse Gas Information System (IG3IS) and the Integrated Carbon Observation System (ICOS) Cities Project, the summit brought together leading scientists, policymakers, urban planners, technology developers, and civic stakeholders. Their shared mission: to accelerate the development and application of innovative methods for urban GHG emissions monitoring and to finalize the IG3IS Urban Good Practice Guidelines—a key milestone in global urban climate governance.

The Urban Climate Challenge: A Call for Action

Although cities occupy only a small fraction of the Earth’s land surface, they are responsible for approximately 70% of global greenhouse gas emissions. Urbanization, energy use, transportation, and industrial activity have made cities both contributors to and victims of climate change. This dual role means cities are critical players in achieving the Paris Agreement targets.

"Cities are at the epicenter of the climate crisis—and the solutions," said Johan Stander, Senior Director of the WMO Services Department. "This summit embodies WMO’s 75th anniversary theme, ‘Science for Action,’ by enabling the science-policy interface that is so essential to protecting communities and improving lives."

Turning Science into Solutions

One of the summit’s primary goals was to demonstrate how scientific research can be transformed into practical tools and policies for urban leaders. Over the course of the three-day event, delegates explored dozens of innovative methods for monitoring and managing urban GHG emissions. A centerpiece of these discussions was the IG3IS Urban Good Practice Guidelines, which outline 31 proven techniques for quantifying emissions.

These methods include:

• Integration of atmospheric observations with emissions inventories

• Remote sensing and satellite data for detecting emission patterns

• Use of activity data, such as traffic or energy use, for real-time monitoring

• In-situ sensor networks deployed across urban infrastructure

• Modelling systems that simulate emissions under different policy scenarios

This wide array of techniques reflects the diversity of urban settings and the unique challenges cities face based on their size, geography, infrastructure, and policy environment.

Bridging the Gap: Science Meets Stakeholders

One of the most impactful aspects of the summit was its commitment to engaging non-technical stakeholders. While cutting-edge tools exist, their effectiveness depends on being understandable, accessible, and actionable by the policymakers, city officials, and community organizations tasked with implementation.

The third day of the conference was dedicated to stakeholder dialogue, where participants discussed:

• Specific data needs of urban decision-makers

• Barriers to implementation such as funding, capacity, or regulatory challenges

• Strategies to promote cross-sector collaboration and data-sharing

• Ways to address knowledge gaps in city administrations

A diverse group of participants, from local government officials to civil society advocates, gathered under a shared commitment to build climate-resilient cities. At one photo-op, a group stood smiling in front of the summit’s branded backdrop, holding a sign that read, “Real Data, Real Impact: Build Climate-Resilient Cities.”

Looking Ahead: A Blueprint for Cities Worldwide

The finalized IG3IS Urban Good Practice Guidelines are expected to become a global reference document for cities aiming to strengthen their climate action plans. With contributions from more than 100 experts, the guidelines provide a flexible yet rigorous framework for cities to measure, verify, and reduce their emissions based on their specific contexts.

As cities continue to set ambitious climate goals—from reaching net-zero emissions to adopting carbon budgeting—reliable, science-based data will be the cornerstone of effective policy.

The Urban Greenhouse Gas Conference and Stakeholder Summit 2025 not only advanced technical expertise but also exemplified a collaborative model for city-level climate governance. It is a reminder that real progress comes when science and society move together—city by city, block by block—toward a more sustainable future.