Why podcasts are one of the most environmentally sustainable advertising mediums — and why it’s time for advertisers to start thinking about EPM

Why podcasts are one of the most environmentally sustainable advertising mediums — and why it’s time for advertisers to start thinking about EPM

Written by Johan Billgrenco-founder and Chief Innovation Officer2022.09.28

As the hottest summer on record winds down, it’s evident to all (or, at least, most) of us that tackling climate change and protecting the environment needs to be prioritized. We all know what we should be doing at home — recycling, switching off the lights and avoiding single-use plastics, for example — but how many of us regularly stop to consider how the technology we use every day impacts the environment?

Whether you’re sending a DM or an email, streaming a video or listening to a podcast, you’re using energy — not just via your hardware, but also through the servers and networks that power it. And it all adds up. 

Today, the internet and its operation represents at least 3.7% of global greenhouse gas emissions — with some groups such as the French think tank The Shift Project claiming this figure could be even higher. Such energy consumption is increasing year by year, with no sign of slowing down. 

In fact, internet emissions now equal those of the oft-cited “scourge of the environment”, the aviation industry*. 

With so many industries so reliant on the internet, it’s no surprise that companies across the world are looking at how they can offset or reduce their impact — and the media industry, including Acast, is no different. There’s increasing awareness among our advertiser partners, podcasters, their listeners and internally within our own business, of the environmental cost of the things we can’t necessarily touch or see.

Perhaps it’s time for media buyers to not only consider the CPM (cost per mille) of a project, but the EPM (emissions per mille), too?

Are podcasts the most sustainable advertising option?

Fortunately for podcasting companies such as Acast, and especially when compared to other advertising mediums, we’re already at an advantage.

While it would be extremely difficult for any digital company to operate at net zero, Essence Global has ranked different media channels by metric tons of CO2 emitted per £1 of media investment — to highlight their relative environmental impact.

According to Essence, online video and display advertising were the worst offenders — followed by cinema, digital audio, and online PPC ads, all significantly lower than video and display. The lowest-ranking channels were newspaper and radio, due to the high recyclability of the former and the low device energy consumption of the latter. 

But there are other important factors to take into account — ones that contribute to digital audio (and in particular podcasts) being even less energy intensive: 

  • Production: In general, producing audio and audio ads requires fewer resources, and very little kit — it’s often as simple as a microphone, a laptop and a voice. Compare that to the creation of visual commercials — be those video or even stills — which usually require a full production crew, travel, lighting, cameras, and so on. It’s clear that, from creation to distribution, the vast majority of audio uses far less energy than any type of visual advertising.
  • Storage, streaming and scalability: Audio files tend to be far smaller than their video equivalents, meaning less energy is needed to upload, store, play and stream them. An ad campaign booked for one million impressions, for example, is going to need far more energy if it’s streaming video versus audio. Or consider how out-of-home ads need to be lit in the evening, or played on video screens over and over — needing a constant power supply.

It can certainly be claimed that shifting to audio ads is better for the environment but, realistically, that’s never going to be the only consideration for a profitable business. 

As Swedish ad tech company SeenThis aptly puts it in The Time is Now, its report on reducing the internet’s CO2 impact, “business decisions that are good for the environment but bad for profit are not truly sustainable.” Environmental, Social and Governance (ESG) strategy will always need to be balanced with return on investment.

But here’s where podcast advertising excels once again. Podcast ads command the highest attention levels of any media channel**, listeners are least likely to avoid podcast ads across a plethora of other options as given***, and, when asked which types of media channel they’re most focused on while consuming, podcasts came second only to watching films at the cinema — ahead of video streaming, video games, radio and live TV****.

With that in mind, you could also argue that podcasting has the highest impact per unit of CO2 emitted. 

People are looking for sustainable brands to champion 

Consumers and investors alike now expect brands to have ESG plans in place, and with sustainability a core pillar. As Right Thing Media, a company specializing in social impact media, says: “Profits with purpose deliver consumer and shareholder confidence. Embedding a social or environmental impact into your responsible investment strategy can be achieved seamlessly without increasing budgets or losing share of voice.” 

And, according to a recent Kantar study, 80% of UK consumers agree that “companies should be doing more to be sustainable”. Numerous studies in recent years have supported the idea that people believe big brands should play as much of a role as governments when it comes to tackling climate change and protecting the environment.

What else do media agencies and advertisers need to consider?

In 2020, the Advertising Association (AA) in partnership with the IPA and ISBA launched Ad Net Zero — an industry-wide initiative aimed at UK advertising, but with guidelines and advice open to all respond to the climate crisis caused by CO2 emissions. 

To mark the launch, the AA published a report by its Climate Action Working Group with Credos, a UK advertising think tank. The report estimated that total UK agency operational CO2e emissions exceeded 84,000 metric tons a year, and the industry as a whole could have a carbon footprint of nearer one million tons. It also revealed that  71% of people working in the industry are worried about its negative impact on the environment, and more people want their agencies to take climate action.

As with so many things, prevention is better than cure. A carbon reduction strategy — which means you’re not causing the need to offset in the first place — is the most impactful choice for both the environment and your own business or brand’s sustainability goals.

Acast’s own ESG strategy, including on climate action and emissions, is aligned with the UN Sustainable Development Goals and additionally work to ensure our service providers and vendors have their own sustainability goals in place. 

We’re committed to measurement, tracking and reduction initiatives, and have already begun work to measure our own environmental impact. This will include the measurement of emissions from our use of electricity, business travel, purchase of IT equipment, and so on. That’s in addition, of course, to the streaming emissions caused by people listening to our podcasts — which is where the majority of our environmental impact comes from. 

If you’re interested in hearing more about podcast advertising as a sustainable medium, contact Acast via We’re working with Right Thing Media, a B Corp for-profit business that empowers brands to deliver on their corporate social and environmental  responsibilities through advertising. To find out more, please contact

*Mike Hazas, researcher at Lancaster University, cited by the BBC

** Nielsen’s Podcast Ad Effectiveness (PAE), Sept 2021

*** Source: Cumulus Media and Signal Hill Insights’ Podcast Download - Spring 2021 Report

**** Q: How immersed/focused are you, in the moment, when participating in the following activities? A: Top 2 boxes (‘Always/Usually focused’) selected on a scale of 5 | Base: All Respondents, Total N=2002 Prepared for: Acast | Podcast Listeners Landscape | Source: Acast/Nielsen Media Analytics Podcast Listener Landscape UK/Ireland Research 2022

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