The average consumer may not realize how much power goes into placing the targeted ad they see online every day. So for many, the hidden impact of digital advertising may come as a surprise: Digital advertising has a massive carbon footprint. A typical digital-ad campaign for a single brand can produce hundreds of tons of carbon dioxide. In the U.K., for example, an average digital ad campaign emits over 5.4 tons of CO2. To put that number in perspective, this accounts for one-half of one consumer’s annual emissions in the U.K. and over one-third of carbon emissions from fossil fuel per capita in the U.S.

The world is failing to reach the Paris Agreement’s target to limit the rise of global warming to 1.5 degrees Celsius in a multitude of ways, so you might be wondering: Why do we need to pay special attention to the amount of CO2 emissions contributed by online advertising specifically? Well, one reason seems obvious: such emissions often go unacknowledged.

Like it or not, the global online advertising industry has a massive influence on everyone, making us all part of the problem. Aside from being a powerful driver of our frequently excessive (and wasteful) shopping habits, the mere daily viewing of multiple search ads, banners, interstitials and video pre-rolls, in addition to hundreds of the so-to-speak digital-out-of-home ads (on the streets, in shopping malls and elsewhere) has a massive impact on the global carbon footprint.

Just think about it: A footprint of one short email is estimated at 0.3 grams of CO2, and this number can grow up to 17g for a longer version, according to Mike Berners-Lee’s research. And how many of those do you get every day? Tens, if not hundreds, and counting.

And while the jury’s still out on whether we can make online advertising carbon-neutral, this key question remains: What actual steps do we need to take to get closer to this goal?

But first, let’s define what carbon neutrality actually means.

What is carbon neutrality?

To put it simply, carbon neutrality implies the amount of carbon emissions is balanced with the amount of absorbed emissions by natural carbon sinks (e.g. rainforests).

So to count as a carbon-neutral company, a business needs to demonstrate its amount of emitted greenhouse gasses are being negated by the amount of adsorbed gasses, either by reducing the number of its emissions or by purchasing the so-to-speak carbon offset credits — in other words, permits to emit a specific amount of greenhouse gasses, like CO2.

Identifying the sources of emissions in the digital ad supply chain

The first step in reducing digital ad emissions is to identify the main sources of these emissions in the digital ad supply chain. When it comes to online advertising, aside from the travel costs, the key sources of emissions include data transmission, data center and device usage in each of the following:

• The production of ad creatives — from equipment rental to post-production and crew travel.
• Programmatic ad transactions — defined as the automated buying and selling of online advertising space — play a huge role in the production of carbon emissions. For example, WPP, the world’s largest investor in media advertising, reports that 55% of its current carbon emissions come from the programmatic supply chain that delivers campaigns on behalf of its clients.
• Ad targeting and measurement — this includes the selection of audience segments, uploading the audience segment to the advertising platform, and the continuous tracking of ad performance by multiple scripts on websites.
• The delivery of ads across desktop and mobile web, connected TVs and mobile apps — for instance, streaming a one-minute video on a 50-inch LED TV in the U.S. reportedly results in 0.98g CO2 emissions, whereas watching the same video on one’s smartphone reduces the carbon footprint by almost six times.

So, what are the possible solutions to reduce digital ad carbon emissions, and who should act on it?

Advertisers need to drive change

While every member of the advertising supply chain needs to do their part towards achieving carbon neutrality, brands and media agencies need to take an extra step, specifically in online ad production and media planning areas.

Namely, the scope of actions may include:

• The localization of ad production so it’s closer to the team’s location to reduce travel-related carbon emissions.
• The use of 3D modeling animation instead of video shooting to minimize the CO2 emissions produced by production crew travels and utilized equipment.
• The production of short video ads, instead of long ones. As a general rule, the shorter the video, the less the file weighs, and the less server load its delivery and streaming require. This, in turn, should result in reduced CO2 emissions by viewers’ devices, data transmission and data centers.
• A reduction of the size of image ads. Similarly to video ads, the lighter the image file, the fewer CO2 emissions it emits.
• The upcycling of existing media creatives by tweaking old video and image ads instead of creating new ones to curtail carbon footprint.
• The delivery of ads during non-peak times in order to balance off-peak server load, which usually requires extra power consumption and results in larger CO2 emissions.

On a broader scale, making a positive change also implies a shift in the perception of brand safety, that is, adding sustainability benchmarks to the picture.

First, this involves defining the brand purpose and actually investing in the promotion of carbon-conscious behavior among the company’s customers.

Second, this means optimizing for or even adding extra incentives for carbon-efficient publishers and ad tech partners (i.e. being willing to pay a higher price for placing ads on carbon-efficient websites, spending more money on carbon-efficient video ad servers, etc.), hence driving the further transformation of the entire ecosystem.

And third, this requires the maximization of return on CO2 emissions, in addition to ROI. In other words, brands need to strive for the maximum reduction of carbon emissions, while maintaining overall advertising efficiency. For instance, a company may choose to target smartphone users with short video ads (e.g. 5- or 10-second long) instead of longer ones, which happen to perform better in the mobile segment.

Related: 4 Ways Smart Maps Can Help Your Business Keep Its Social Promises

But real change cannot be achieved without digital ad consumers

While the majority of top-tier brands — like the members of the World Association of Advertisers (WFA) — have already made their Planet Pledge, and tech giants such as Microsoft and Google have reaffirmed their sustainability commitments, actual positive change would not be impossible without digital ad consumers.

Even though most businesses’ carbon-neutrality promises sound ambitious, chances are the reported data is being miscalculated, misrepresented or both. It’s up to us, the consumers to keep them accountable, by doing the following:

• An analysis of climate pledges that have already been made. You can do this by reviewing the brand’s website and other digital resources to find out which promises on CO2 carbon footprint reduction have already been made.
• Continuously monitoring progress achieved. For example, check if the brand publishes regular reports on how it has been reducing carbon emissions in the past quarter, year, and so on.
• Staying alert for the greenwashing red flags. A company that doesn’t share granular data on emissions, or keeps the message brief, like “We’ve cut emissions by half and now we’re carbon-neutral” are all common signs of greenwashing.
• Being ready to leave, if the expectations haven’t been met. You might find out your favorite brand has been caught lying or misrepresenting its data on CO2 emissions multiple times. Taking a stand by quitting the use of its products or services ensures they’re being held accountable for deceptive and unethical marketing practices.

Ultimately, it’s up to each of us to make our own carbon-conscious decisions, when it comes to our media perception, ad consumption and our shopping habits. If we don’t, we’ll pay an even greater price.