How Dirty Is Your Website? Here Are the Top 100 US Advertisers by CO2 Emissions

When you think of carbon emissions, what comes to mind? The dirty smokestacks of an oil refinery? Clouds of diesel exhaust? While those sources of emissions are very real—and very visceral—the complicated truth is that nearly everything we do has some kind of climate impact. And given the drastic emissions cuts society must make to meet the goals scientists say will mitigate the worst impacts of climate change, every bit counts. Even from places that feel less intuitive. A new report from agency Footsprint aims to highlight the emissions created from a source that's harder to visualize: internet traffic. Focusing on the top 100 U.S. advertisers based on media spend, the group ranked the companies' websites from lowest to highest in terms of the carbon emissions created with each pageview. Did Patagonia’s Founder Just Launch Us Further Into the Green Vortex? "It's all linked to energy," explained Elisa Boivin, managing director at Footsprint and lead author on the new report. Footsprint, a division of French digital marketing performance agency Labelium, launched in April. "When you look at the emissions generated by a website, there [are] three key sources," she said. Those include data centers, transmission networks and user equipment (mostly cellphones and laptops). To calculate how each segment generates emissions, Footsprint looked at the full lifecycle of each category—including production, manufacturing and usage. Brands are ranked in the report according to how much carbon is emitted each time someone visits their main webpage. It also lists yearly emissions for each website based on traffic. "We see opportunities where brands can pioneer on this and be perceived as leaders in the sector and drive change," Boivin said. The hidden cost of clicks Based on Footsprint's methodology, annual carbon emissions from internet traffic amount to roughly 10 million tons. That's about the same as the electricity it takes to power all the homes in Los Angeles for a year, the report notes. Traffic to the top 100 U.S. advertisers' websites alone emits about 161,000 tons of carbon emissions each year, according to the report. It takes more than 7 million trees to sequester that much of the pollutant. Media agencies have begun work to measure the climate impact of digital advertising, largely through carbon calculators. A group of media and tech companies including dentsu, Netflix and BBC launched Dimpact to this end in 2019, for example, and GroupM released its own methodology for measurement over the summer. But the crucial next step for the industry is standardization of these measurement tools—for both website traffic and digital advertising. "What the industry really lacks is standardization," Boivin said. "Our efforts are to really focus on working with the institutions that will be dictating the norm of tomorrow." So, who's winning? The website with the lowest impact based on carbon emissions is, admittedly, almost a joke. Berkshire Hathaway's basic html landing page emits just 0.006 grams of CO2. The company's measly traffic generates 0.02 grams of CO2 in a year. "Their website is from, like, 1997 or something," Tom Greenwood, co-founder of Whole Grain Digital, told Adweek through laughter. Still, it's a really useful page to highlight, he said, because it points out how software has developed over the last 30 years. "The hardware is getting more efficient, but the software is getting less efficient," he said. "We should look at ourselves in the mirror and say, 'Well, what's happening here? What's led to this massive increase in data consumption and computational consumption? Is it all necessary?'" Greenwood wrote a 2021 book called Sustainable Web Design. He's been working on the issue for around 20 years. Although Greenwood wasn't involved with Footsprint's report, he spoke to Adweek about how this research could help nudge the industry in the right direction. "There are some companies that have got really good websites that are really efficient," he said, "and then you've got PepsiCo, at No. 100." PepsiCo's website was the heaviest, according to the report, in terms of carbon emissions per pageview. One visit emits 1.155 grams of CO2. A lot of those extra emissions can be trimmed away through better design, the report explains. Simple fixes include finding green servers for data, compressing and resizing content, and integrating "lazy loading" so that the lower part of the webpage is only downloaded if the user scrolls to it. Those can all make big impacts—especially if a website gets a lot of traffic. Adweek reached out to Berkshire Hathaway, Intuit, Facebook, GlaxoSmithKline, Dish and PepsiCo for comment on this story. None responded by press time. Achieving ‘Mainstream Green’ is Key in Accelerating Transition to a More Sustainable Economy Facing the skeptics Footsprint is careful not to over- or understate the overall climate impact of digital activities. Juan Sotés, the agency's impact measurement director, initially approached the topic with skepticism. In the face of carbon-intensive industries like agriculture and construction, one may wonder, should we really be focusing on websites? What shifted Sotés' thinking was taking a long-term view of energy demand, especially as we work to move away from fossil fuels. Electrifying our homes, cars and everything else is going to put a lot of strain on the grid. To mitigate that strain, everything—especially our ever-expanding digital world—must become more efficient. "What we are facing is a huge spike in electricity demand in the next 20 years, and a lot of problems to meet this demand with green energy," Sotés told Adweek. "It doesn't matter if [electricity consumption is] coming from a car from our laptops. We need to do our best to limit all kinds of electricity consumption. Our grids are in trouble."