Websites produced for COP conferences emit up to 10 times more carbon than average internet pages, according to a new study.
As this year's United Nations climate summit kicks off in Brazil, researchers have revealed a sharp increase in the carbon emissions generated by the conference's websites over time.
Analysis indicates that between 1995 – when the first Conference of the Parties (COP) was held – and 2024, average emissions from COP host websites have risen by more than 13,000 per cent.
And this year's page is set to emit the equivalent of 313kg of CO2 – the amount of carbon that would take 15 mature trees a whole year to absorb.
While the increase is partly the result of huge growth in computing power and internet use, the carbon footprint of COP sites is still significantly higher than the average webpage, scientists said.
This is likely due to COP pages increasingly using content that requires greater computing power, such as high–res images and videos, they explained.
'We chose first to look at the COP conferences themselves, given they are the focus of so much discussion on climate change,' Professor Melissa Terras, from Edinburgh University, said.
'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.'
For their study, the team analysed web archive data to assess changes in the carbon footprint of COP websites over a 30–year period.
Their findings, published in the journal PLOS Climate, revealed emissions remained relatively low until COP14 in 2008, with sites emitting the equivalent of 0.02g carbon per page view.
However, from COP15 onwards emissions have risen sharply, with pages emitting the equivalent of more than 2.4g of carbon per visit on average, with some emitting substantially more.
In contrast, the average website emits the equivalent of 0.36g of carbon per page view, the team said.
PhD student David Mahoney, who also worked on the study, said: '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.
'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.'
The homepage for last year's COP, which was held in Baku, Azerbaijan, features a moving video at the top of the screen along with photographs that expand when a mouse is hovered over them.
Meanwhile the homepage for COP28, held in Dubai, features three main videos and a moveable sliding 'status report'.
The conference with the highest average CO2 emissions per page view was from COP25, which was held in Madrid, the study indicates.
The website created for that conference was 'heavily media based…with some individual webpage links dynamically updating content', the paper reads.
This kind of multimedia requires greater computing power than older websites, which will have been much more basic.
The team suggest several ways to reduce the carbon footprint of websites including placing strict limits on page sizes, optimising layouts and hosting websites on servers powered by renewable energy.
