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Views of webpages used for the Conference of the Parties (COP) sites—referring to the annual United Nations climate change summit—emit up to 10-fold more carbon emissions than average site views. Leaders from around the world—with the notable exception of the U.S.—are on their way to Belém, Brazil, for the 30th United Nations Climate Change Conference, COP30, which takes place from November 10 to 21. COP is the main decision-making body of the United Nations Framework Convention on Climate Change (UNFCCC) Researchers from the University of Edinburgh in Scotland have revealed average emissions from COP conference websites have “dramatically” risen by more than 13,000 percent between 1995 and 2024. “Some individual pages of more recent COPs measured 10 times the global average of approximately 0.36 g of CO₂e per pageview,” study author PhD student David Mahoney told Newsweek. “The COP25 website (average of 10 pages tested) emitted up to seven times more than the global average. “Emissions generated by just the recorded in-session participants have risen by over 80,000 percent between COP3 in 1997 and COP29 in 2024, rising from roughly what a tree absorbs in two days to the yearly absorption of five to 10 mature trees. This illustrates how the scale of the conference compounds the cumulative impact of these larger websites.” Newsweek has reached out to the United Nations Framework Convention on Climate Change (UNFCCC) via email. The researchers acknowledge the internet contributes more today, with 5,5 billion users, than it did in the 90s in terms of greenhouse gas emissions—an estimated 1.5 percent to 3.2 percent. That being said, they argue the carbon footprint of COP sites is still significantly higher than the average webpage. Their findings reveal emissions remained relatively low until COP14 in 2008, with sites emitting the equivalent of 0.02g carbon per page view. This continued to rise more rapidly from COP15, with pages on average emitting the equivalent of more than 2.4g of carbon per visit and some substantially more, the team report. “According to Website Carbon, a tool for measuring the emissions of websites, the average CO₂e emission per pageview globally is approximately 0.36 g,” said Mahoney, adding that the calculation of many recent COP sites being 10 times that. The rise also reflects COP pages increasingly using content that requires more computing power, like scripts and multimedia files. Larger page sizes have been found to dramatically amplify emissions as site traffic grows. The researchers noted that as COP30 had not yet taken place at the time of the study, participant numbers are not yet available and it was excluded from the analysis. Their findings are intended to showcase the growing environmental impact of COP host websites. The authors have suggested practical recommendations for reducing this digital footprint and paving the way for positive change. “Websites should be hosted on verified renewable energy infrastructure and follow best practices such as those outlined in the W3C’s Web Sustainability Guidelines. Simple interventions, such as setting a page-size budget and optimizing media can help in reducing the environmental impact of a website,” explained Mahoney. “A desired outcome would be for the UNFCCC to lead by example and ensure that for COP31 the host country agreement annex includes sustainable web design as a recommended, or ideally a required activity. “Furthermore, I hope this research highlights a persistent problem in one of the largest and longest-standing forms of human-computer interaction: websites, and raises awareness of this issue among other organizations.” Mahoney noted the UN’s Greening the Blue initiative has connected him with the UNFCCC and he has shared the results with them ahead of this paper’s publication, which came after the COP30 website went live. Do you have a tip on a science story that Newsweek should be covering? Do you have a question about website emissions? Let us know via science@newsweek.com.
