The hidden carbon cost of digital advertising – and what we can (and should) do to tackle it.

From how and why emissions are generated to what we can do to start decarbonizing our media campaigns: everything you need to know about the hidden carbon cost of digital advertising.

Have you heard about the heavy toll of digital advertising? Today, learn more about the environmental cost of our media campaigns from main contributing factors to opportunities to tackle the issue.

The heavy toll of digital advertising: what are we talking about?

Worldwide digital activity is estimated at 1.2 billion tons of CO₂e per year, more than any country aside from China and the USA. The digital sector today accounts for 2 to 4% of total global emissions, and most of those emissions are related to the energy and materials needed to manufacture data centers, transmission networks and our end devices (laptops, smartphones, etc.). The other main source of emissions is the electricity consumption needed to operate the infrastructure, called operational emissions.  

More than half of the operational emissions in the internet are generated by video streaming, the rest are split between websites, online gaming, cloud storage and others. There is, however, one source of emissions that is often not included in the analysis: the emissions linked to digital advertising.

In recent years, we have seen a significant shift of advertising dollars from traditional to digital channels. In 2022, the global digital advertising market is valued at $600B, or 66% of the overall expenditure in media ads (eMarketer). And digital advertising growth is showing no signs of stopping: projections from industry experts forecast sustained growth over the next few years, despite a relative slow down in growth rate. By 2025, the sector is forecasted to grow to pass the $800B bar. 

Yet digital advertising campaigns carry a cost for the planet. Our recent analysis shows that a typical Youtube campaign in the US can generate 6.7tCO per 100K$ invested for distribution only. At sector level, this means our $600B in digital media are estimated to generate about 40M tCO each year, which is almost as much as a country like Sweden. If we include creative production (shooting and editing content) into our analysis, this estimate is likely to double. 

Why and how do digital campaigns generate carbon emissions?

In other blog articles, we will go more in depth on the impact of creative production, but for today we will focus on the impact of media distribution across the digital ecosystemThe carbon impact of digital ads takes place in several places across the digital ecosystem: in data centers where ads are stored, in the networks where they are distributed, and in the devices where they are finally displayed (see infographics)

The focus of this article is to explain the characteristics of those ads that determine the climate impact of an impression in its journey from the data centers to our devices, and what we can do to mitigate them. 

The impact of an impression is directly related to the amount of energy needed to store, transfer and display it, combined with the carbon intensity of the energy source. The main variables that affect this energy consumption are:

The amount of energy needed to send an ad through the internet is directly correlated with the quantity of data transferred, which can vary based on several characteristics:

(1) Ad type: Videos are heavier than images and will have a higher energy needs and therefore more carbon impact per impression.

(2) Video length: The longer the videos the more data will be transferred, watching a 30-second ad will generate twice as much emissions as watching a 15-second one.

(3) Compression rate: Creatives undergo different levels of compression depending on the platform, device and network quality. If we manage to optimize ad compression, it is possible to significantly reduce their impact. For example, a video with a 720p resolution is 3 times more energy consuming than one at 480p, with minimum difference in quality specially in smaller screens like our smartphones .  

Even if ads require the same amount of energy regardless of location, how this energy is generated can vary significantly depending on the proportion of energy generated with fossil fuels

(1) Location: Each grid has a different mix of electricity generators, those with a higher proportion of renewable sources will generate less emissions per kWh. For example, an ad displayed in Texas will generate more than 200 times more emissions than the same ad displayed in Quebec.

(2) Time: Even within the same grid, the amount of energy generated with fossil fuels varies depending on total demand, which follows a similar daily pattern.

As we increase our activities, toward the end of the afternoon, electricity grids need to use more energy, requiring fossil fuel generators to increase production and therefore the overall grid’s carbon intensity. Avoiding this peak time in ad distribution, normally between 4pm and 7pm, will reduce the campaign’s overall climate impacts.

The energy required to display an ad in the end device varies significantly. For example, accounting for full lifetime impacts,  the same ad displayed in a smartphone will require twice as much energy as one displayed in a computer.

Ads travel from data centers to our end devices via different transmission networks, each one of them with different energy requirements. An ad distributed via mobile networks (4G, 5G, etc.) will require five times more energy than via WiFi.

What can we do to start decarbonizing our media campaigns?

The good news is that we can take immediate action to reduce the emissions generated by our media campaigns. 

Our studies show that by taking direct action on some of the key optimization pillars listed above, we can reduce the carbon emissions of a single video campaign by up to 80% without impacting media performances. But where should we start? 

The key to reconcile sustainability with performance is to integrate environmental performance as a new dimension into our rigorous media performance management process.

To do this, three key steps are fundamental: 

The first critical stage to the journey is to begin with measuring and visualizing the environmental performance of our media campaigns. This first stage requires the establishment of rigorous environmental metrics tied to our campaigns, such as CO emitted per thousand impressions.

This visualization will enable us to identify high reduction potential channels, and to view our media results through a new lens.

Just like in regular account management, structural quick wins can go a long way in improving performances.

Identifying and implementing the low risk – high impact wins that will tangibly reduce emissions on high reduction potential channels is a critical milestone in the journey

Yet, and again, just like in regular account management, structural quick wins and continuous improvement are two very different things.

This stage requires continuous A/B testing and monitoring of our campaigns so that we can set our environmental metrics and a continuous reduction path, in a similar fashion to our ongoing optimization of media unitary costs.

A look beyond digital emissions...

Beyond direct carbon emissions generated by advertising, governments and companies are starting to look into the types of behaviors and consumerism that advertising is actively promoting

New regulations, such as the “Contrat Climat Publicité” in France, are forcing brands to take a close look at the type of products they are putting advertising dollars behind, as well as the type of purchasing patterns they are encouraging. 

More and more, brands will be accountable for driving consumption patterns towards more durable products, consistent with sustainable lifestyles, and advertising has a tremendous role (thus responsibility) to play in this. 

And brands should see this as an opportunity rather than a constraint, for this is in line with new customer expectations. When 45% of Gen Z stop purchasing brands because of sustainability or ethics concerns as a main factor (NielsenIQ – Global, 2021), we can be sure that this shift should be a business priority for brands to stay relevant in the years to come. 

Let's act now!

At footsprint, we elaborate tailored plans to help mitigate your carbon emissions while delivering on business performance. Reach out to our experts at solutions@footsprint.agency

Elisa Boivin


Elisa joined Labelium 7 years ago and focused as a Media Director on accompanying large, fast-growing brands specializing in the Luxury, Fashion and Beauty industries. In 2020, she joined the Labelium Americas Marketing & Consulting team as Program Director, overseeing large international RFPs for the agency and developing new services for the region. In 2021, she was named ESG Director for the region spearheading Labelium’s first ESG materiality analysis and uncovering a gap in today’s ESG auditing methodologies in measuring the carbon footprint of digital advertising.

Juan Sotés


Throughout his more than 10 years of experience in environmental sciences and global warming, Juan has worked in both private and public sectors, and more specifically for the Toronto Atmospheric Fund as carbon and co-benefits analyst. He joined footsprint in order to help the industry accelerate the transition towards digital sobriety. His expertise in carbon measurement and GHG protocols will contribute to develop and strengthen industry frameworks.

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