Why Now: A Standard the Industry Has Been Waiting For

For years, one of the most persistent barriers to sustainable media planning was fragmentation. Advertisers who wanted to understand the carbon impact of their campaigns faced a patchwork of competing methodologies, inconsistent data from media partners, and no agreed baseline for comparison. A digital impression measured by one method could produce a carbon figure three times higher than the same impression measured by another. That inconsistency did not just create confusion. It gave organisations a ready-made excuse to defer action.

That excuse no longer holds. In June 2025 at Cannes Lions, Ad Net Zero published GMSF v1.2, a major update to the Global Media Sustainability Framework that now includes standardised formulae for all six major media channels: Digital, TV, Out-of-Home, Print, Audio and Cinema (Ad Net Zero, 2025). The framework is the result of more than a year of collaboration across the world's six largest advertising holding companies, leading global advertisers, media owners, tech companies and trade associations, including the IAB, IPA, WFA and GARM.

This is not a niche initiative. Supporters include Google, Meta, GroupM, Omnicom, Publicis Groupe, Dentsu, L'Oréal, Mastercard, Diageo and Unilever (Ad Net Zero, 2025). When the infrastructure of global advertising aligns around a single digital advertising carbon measurement standard, adoption stops being optional.

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The Evidence: What We Know About Advertising's Carbon Footprint

The urgency behind the GMSF is grounded in data, not sentiment. Advertising's environmental footprint is substantial and, until recently, almost entirely invisible to the teams responsible for it.

Research from sustainable ad tech company Good-Loop estimates that a significant volume of carbon is generated with every digital ad impression at scale. Multiply that across billions of daily impressions and the cumulative figure becomes material (Good-Loop, 2024). According to Purpose Disruptors, advertised emissions (the carbon generated by products and services people purchase as a result of advertising) rose by more than 10% between 2019 and 2022 (Purpose Disruptors, 2023).

Despite this, awareness remains low. Good-Loop found that over 66% of brand marketers feel there is insufficient education and training on sustainable media, with many saying they want to act but do not know where to start (Good-Loop, 2024). This is precisely the gap the GMSF is designed to close: not just providing a framework, but giving marketers the language, methodology and confidence to embed carbon into every media plan.

The digital channel now has the most detailed data guidance available. GMSF v1.2 includes comprehensive Digital Data Guidance developed by IAB Europe's Methodology and Framework Working Group, covering formulae, data levels and default values specifically for digital advertising (Ad Net Zero, 2025). For campaigns where log-level data is available, it is possible to go well beyond baseline estimates and produce highly accurate, campaign-level emissions figures.

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What Leading Brands and Agencies Are Already Doing

The GMSF is voluntary. The major players are not waiting to be told.

Several of the world's largest advertisers have already begun integrating carbon measurement into their media planning processes, and the early movers are finding commercial benefits alongside the sustainability credentials. IPG Mediabrands committed to tracking the environmental impact of media campaigns using GMSF-consistent metrics. Martin Bryan, Global Chief Sustainability Officer at IPG Mediabrands, described the framework as enabling the "critical work of reducing the climate impact of media campaigns on behalf of our clients" (Ad Net Zero, 2025). GroupM, the world's largest media agency group, was a founding supporter throughout the GMSF development process.

The pattern among early adopters is consistent. Building carbon measurement into media planning workflows identifies waste, improves supply chain transparency and strengthens positioning in pitches and procurement conversations. Agencies that can present clients with verified campaign-level carbon data are differentiating themselves in a market where sustainability credentials are increasingly a commercial requirement, not just a reputational one.

The business logic is straightforward. Media supply chains that are high in carbon tend to be high in waste. Programmatic inventory with inflated carbon footprints typically involves excessive intermediary layers, poor viewability and low-quality placements. Cleaning up a media plan for sustainability reasons and cleaning it up for performance reasons tend to produce the same result: fewer wasted impressions, better working media ratios and stronger return on investment.

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The Practical Framework: Four Steps to GMSF Compliance

Implementing the GMSF does not require starting from scratch. For most marketing teams and agencies, the path to compliance follows a clear sequence.

Audit your current measurement approach. The GMSF includes a disclosure form that allows advertisers to assess the scope, data quality and scientific validation of any existing sustainability measurement they have in place. If your current approach does not align with GMSF methodology, the first step is understanding the gap. Ad Net Zero has published guidance specifically for advertisers on the right questions to ask (Ad Net Zero, 2025).

Establish a baseline across your media mix. Before you can reduce, you need to measure. The GMSF provides default values for all six channels, meaning complete log-level data is not required to begin. For the digital channel in particular, detailed data guidance now makes it possible to produce campaign-level emissions figures using existing data inputs. Platforms like EcoMetrics automate this process by integrating directly with your live campaign data across Google Analytics, Meta, YouTube, LinkedIn, TikTok and email marketing tools, calculating your carbon baseline without adding complexity to your team's workflow.

Make carbon a live consideration in media planning. The GMSF guidance explicitly asks agencies to make greenhouse gas emissions a consideration for all media plans (Ad Net Zero, 2025). In practice, this means including a carbon metric alongside reach, frequency and CPM in media evaluation. It does not require sacrificing performance. Research consistently shows that lower-carbon inventory also tends to be higher-quality inventory, delivering better return on investment because it cuts out the layers of waste that generate unnecessary emissions in the first place.

Report and disclose with verified data. Advertising emissions typically fall under Scope 3 of corporate carbon accounting, the category that covers indirect emissions across the value chain. As corporate sustainability reporting requirements tighten under the EU's Corporate Sustainability Reporting Directive (CSRD) and equivalent frameworks in other markets, having verifiable, methodology-compliant data is becoming a finance and legal requirement as much as a marketing one. EcoMetrics is built around GMSF-aligned methodology developed in partnership with Sheffield Hallam University, giving marketing teams data that can feed directly into verified sustainability reporting rather than sitting in a separate silo.

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The Opportunity Ahead

The GMSF is a first iteration, not a finished product. Ad Net Zero has signalled two significant workstreams for 2025 and beyond. The first is an Audit and Verification process to third-party certify GMSF-compliant carbon calculators, ensuring the data underpinning sustainability claims can withstand scrutiny. The second is a centralised Data Collection and Access system that will allow emissions data to flow between media buyers and sellers at scale, replacing today's fragmented bilateral approach with something closer to a common currency (Ad Net Zero, 2025).

When that infrastructure is in place, carbon data will move through the media supply chain in the same way viewability data does today. Media owners who cannot provide GMSF-compliant emissions figures will face questions from buyers. Advertisers who cannot produce verified campaign-level carbon data will face questions from procurement teams, investors and regulators.

The IPA's Director of Media Affairs framed the significance of the framework directly: "Having agreed standards for calculating media supply chain emissions is the cornerstone of decarbonising commercial media" (IPA, 2025). That cornerstone is now in place. What gets built on top of it depends on the decisions marketing teams make over the next twelve months.

Sebastian Munden, Chair of Ad Net Zero, described this moment as "the business opportunity of a generation" for the advertising industry (Ad Net Zero, 2025). That framing matters. This is not a compliance burden being imposed on an unwilling industry. It is a structural shift in how media value will be assessed, procured and reported over the coming decade, and the organisations that move now will be significantly better positioned than those that wait.

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Conclusion: The Measurement Era Has Arrived

The GMSF has resolved advertising's most persistent excuse for inaction on digital advertising carbon measurement: the absence of a common standard. The framework now exists. It has industry-wide support from the largest brands, agencies, media owners and platforms in the world. The methodology is clear, the tools are available and the business case is well-established.

For marketing teams, the next step is operational. Building carbon measurement into media planning now, using GMSF-aligned data that connects to both campaign performance and corporate sustainability reporting, is the move that separates leaders from laggards. For agencies, it is a genuine commercial opportunity to guide clients through the transition before procurement teams and investors start demanding it.

EcoMetrics exists precisely for this moment, giving marketing teams the cross-channel measurement, campaign-level data and verified reporting infrastructure to make digital advertising carbon measurement a live part of how they plan, buy and evaluate media. The standard is in place. The window for first-mover advantage is open.

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