GMSF 1.3 Just Raised the Bar on Ad Carbon Measurement: Here's What Pyure Sees Changing

The GMSF is the advertising industry's shared methodology for calculating greenhouse gas emissions from media campaigns. While it doesn't do the calculating itself, you can think of it as the rulebook that measurement tools build on, so a number produced in London means the same thing as a number produced in Tokyo.

Version 1.2, released at Cannes Lions 2025, was a strong foundation — it moved the industry toward activity-based measurement: real impressions, real data transfer, real video seconds. Countless organizations, including many of our clients, have built reliable reporting on top of it. Version 1.3 builds on that same foundation and extends it further.

Every few years, an industry standard takes a meaningful step forward. GMSF 1.3 is one of those moments. Unveiled by Ad Net Zero at Cannes Lions 2026, it's the most significant update yet to the Global Media Sustainability Framework, the industry's shared methodology for measuring carbon emissions across media.

At Pyure, we spend our days elbow-deep in media data, normalizing it, reconciling it, making sense of it across every platform that touches a campaign. So when a framework like GMSF evolves, we pay close attention to what it means in practice. Here's our take on what's new, and why we're excited about where it's heading.

GMSF's reach just got significantly wider. Coverage now extends to media representing roughly 95% of worldwide ad spend, the broadest the framework has ever offered. It's a natural next step for a standard that's been steadily expanding since launch.

Version 1.3 introduces dedicated implementation guidance for television, OOH, and print, alongside a refreshed digital methodology. This is one of the changes we're most excited about. It means even more channels benefit from the same level of consistency and rigor that digital has had. Audio and cinema guidance is on the way later in 2026, rounding things out further and taking the specific methodology beyond considering these as video-like channels.

This is exactly the kind of allocation challenge we deal with constantly at Pyure: how do you fairly attribute a shared cost — in this case, a company's overhead emissions — across campaigns and clients? Version 1.3 introduces a clear, standardized answer, adding another layer of consistency to reporting.

Guidelines now include the standardization of an uncertainty indicator. This transparency signal shows how much of a given figure is based on activity data versus modeled defaults. It's a thoughtful addition that gives teams even more confidence and clarity when presenting numbers to stakeholders or auditors.

Version 1.2 gave the industry a strong, activity-based way to measure the energy consumed during ad delivery and viewing. Version 1.3 builds on that by additionally incorporating a life-cycle perspective, helping to account for things like the manufacturing footprint of hardware in the delivery chain, a more granular read on programmatic chain depth, and updated emission factor datasets.

Because 1.3 captures more of the full picture, campaigns measured under the new methodology will naturally show different — potentially higher — totals than the same campaigns measured under 1.2. That's simply because the scope of what's being measured has expanded, not because anything about earlier reporting was inaccurate. Numbers produced under 1.2 reflected exactly what that version was designed to measure, and remain a solid, trustworthy baseline for the comparisons and trends built on them.