The Intergovernmental Panel on Climate Change (IPCC) has opened the expert review of the First Order Draft (FOD) of its Special Report on Climate Change and Cities, marking a critical step toward the organization’s seventh assessment cycle.

At its Forty-third Session in Nairobi, Kenya (11–13 April 2016), the IPCC decided to dedicate a special report to the complex links between climate change and urban environments. Following a global call for nominations in August 2024, Coordinating Lead Authors, Lead Authors and Review Editors were selected in December 2024. These authors have now prepared the first draft, which is available for expert review from 17 October to 12 December 2025 (midnight GMT +1).

To provide more details on the review process and how scientists can get involved as reviewers, IAP and the IPCC Focal Point for Italy hosted a webinar on 18 September, which was attended by more than 100 interested researchers from around the world. The webinar recording is available to view on Youtube, while a Quick Guide summarizing the main information, timings and links can be downloaded below.

Why This Review Matters

The expert review is designed to ensure that the report offers a balanced, transparent, and comprehensive assessment of the latest science. According to IPCC procedures, the process is open to a wide range of independent experts –  scientists, practitioners, and policy specialists – representing diverse disciplines and regions.

Governments and accredited observer organizations, including IAP, are encouraged to invite additional experts to participate. Individuals who were nominated for author roles but not selected will receive separate invitations to register.

Key Dates and Registration

• Review period: 17 October – 12 December 2025 (midnight GMT +1)
• Registration deadline: 30 November 2025 (midnight GMT +1)
• Registration link: Register here as an Expert Reviewer

Questions about the process can be directed to the IPCC Working Group II Technical Support Unit at tsu@ipccwg2.org

Resources for Prospective Reviewers

To support participation, the IPCC and partners provide several helpful materials and webinars:

• How to Review IPCC Assessment Reports: Webinars and Guidance for Climate Experts
• Outline of the Special Report on Climate Change and Cities
• Register here as an Expert Reviewer by 30 November 2025
• You can find the drafts and review products of the WGII AR6 here
• Mini E-course Webinar 1: How does the IPCC work?
• Mini E-course Webinar 2: How to conduct an IPCC review

Next Steps

This expert review precedes the government and expert review of the Second Order Draft, scheduled for 8 May to 3 July 2026.

Experts worldwide are urged to lend their knowledge to this critical assessment, helping ensure that cities – where more than half of the global population now lives – are effectively represented in global climate science and policy discussions.

Revisit the Webinar

Revisit the webinar recording — available on Youtube and hear an in-depth discussion of the expert review process.
Anna Pirani, IPCC National Focal Point for Italy and AR7 Lead Author, and Andrew Okem, Head of Science, IPCC WGII Technical Support Unit, share their insights, with moderation by Peter McGrath, IAP Coordinator.