COP websites produce 10 times more carbon than average sites, Scottish researchers find

Websites designed for cop conferences emit up to 10 times more carbon than average internet pages, new research from the University of Edinburgh suggests.  

As cop30 starts in Brazil this week, researchers revealed that average emissions from cop conference websites rose by more than 13,000 per cent between 1995 and 2024.

“Our research shows that the carbon cost of digital presence is often overlooked by even those who care about, and are meant to protect, the environment,” said Professor Melissa Terras of the Institute for Design Informatics at Edinburgh College of Art, which is a part of the University of Edinburgh. “We hope that our recommendations, and our tool, can help institutions identify and tackle this issue.”

The research focused on the impact of an individual internet user’s visit to cop websites. Researchers analysed data from web archives to assess changes in the carbon footprint of the sites. The analysis is the first example of web archives, such as the Internet Archive, being used to track websites’ environmental impact over time the researchers claim.

Total website views during cop3 in 1997 emitted the equivalent of 0.14kg of carbon, roughly the amount of carbon that a mature tree can absorb in two days.

In contrast, it would take up to 10 mature trees a full year to absorb the levels of carbon emitted as a result of cop29 homepage visits alone, which sit at over 116kg – an increase of more than 83,000 per cent from 1997.

While the change is partly a consequence of huge growth in computing power and internet usage worldwide, the carbon footprint of cop sites is still significantly higher than the average webpage, the researchers say. The rise corresponds with cop pages increasingly using content that requires greater computing power, such as multimedia files.  

“While AI rightly captures much of today’s attention, websites remain the longest-standing and most widespread form of human–computer interaction, and one of the largest contributors to the internet’s environmental impact,” said David Mahoney, a PhD student who contributed to the project. “Our work shows how reusing web archives can expose this growing blind spot, even among organisations at the heart of climate discussions, and help identify practical ways to cut digital emissions.”

Digital emissions are estimated to make up around four per cent of global greenhouse gas emissions. This comes through the significant energy cost of running data centres, networks and the eventual end user accessing the internet.  

The researchers recommend that websites should place strict limits on page sizes, optimise site layouts to increase efficiency, and host websites on servers powered by renewable energy.

Currently it is too early to predict the potential environmental impact of the cop30 website, but the researchers highlight that the website is not hosted on “verified renewable energy infrastructure”.