A new report by energy comparison site Uswitch has analysed the carbon footprint of the world’s most popular websites to highlight the environmental impact of our digital lives.

From sending emails and streaming content, to internet shopping and posting content on social media, everything we do online uses electricity. In turn, this produces carbon which negatively affects the environment and can lead to climate change. So, to shed some light on the lesser-known impact of using the internet, the study reveals which of the world’s most popular websites are the cleanest and dirtiest when it comes to carbon emissions.

 The Good, The Bad, And The Dirty

Taking the top spot as the ‘dirtiest’ website is the self-titled ‘front page of the internet’, Reddit. The website is used by millions of people around the world as a place to share news, content and discussions. According to the data, a single visit to the website leads to 13.05g of CO2 emissions.

Another highly used social network comes in as the second dirtiest website, the image sharing site Pinterest emits an estimated 12.43g of carbon from every visit to the site. The gaming website Nintendo, where you can purchase games and consoles, is the third most ‘dirty’ website – every time someone visits the site, it produces an estimated 11.43g of CO2.

In contrast, the cleanest website is one of the most visited online resources in the world, Wikipedia. The website only produces an estimated 0.04g of carbon per visitor. LinkedIn, the professional social network, comes in at second place – emitting just 0.23g of CO2 for every visit, and international fashion brand H&M follows closely behind in third, with 0.29g of carbon being emitted with each visit to their site.

Top 25 Dirtiest Websites:

  Website Website type Amount of carbon per website visit
1 reddit.com Social media 13.05
2 pinterest.com Social media 12.43
3 nintendo.com Gaming 11.43
4 accuweather.com Weather 9.71
5 espn.com Sports 6.8
6 victoriassecret.com Fashion 6.64
7 uniqlo.com Fashion 5.22
8 nytimes.com News 4.64
9 ebay.co.uk Auction site 4.53
10 alibaba.com Ecommerce 4.43
11 zoom.us Video calling 4.28
12 ikea.com Homeware 3.52
13 wayfair.com Homeware 3.21
14 twitch.tv Streaming 3.16
15 weather.com Weather 3.13
16 cnn.com News 3.07
17 bbc.co.uk News 2.95
18 shein.com Fashion 2.88
19 steampowered.com Gaming 2.72
20 currys.co.uk Technology 2.64
21 amazon.co.uk Ecommerce 2.54
22 office.com Technology 2.26
23 shutterstock.com Stock imagery 1.92
24 next.co.uk Fashion & home 1.89
25 youtube.com Video streaming 1.85

Top 25 Cleanest Websites:

  Website Website type Amount of carbon per website visit
1 wikipedia.org Resource 0.04
2 linkedin.com Social media 0.23
3 hm.com Fashion & home 0.29
4 messenger.com Social media 0.29
5 paypal.com Financial service 0.34
6 familysearch.org Ancestry database 0.40
7 wordpress.com Website platform 0.43
8 experian.com Financial service 0.44
9 marksandspencer.com Fashion & home 0.45
10 coinbase.com Financial service 0.49
11 wish.com Ecommerce 0.49
12 shopify.com Website platform 0.54
13 indeed.com Recruitment 0.58
14 spotify.com Music streaming 0.58
15 craigslist.org Listings website 0.61
16 t.me Social media 0.61
17 asus.com Technology 0.65
18 ubereats.com Food delivery 0.66
19 zara.com Fashion & home 0.67
20 sainsburys.co.uk Supermarket 0.68
21 fedex.com Courier 0.70
22 archiveofourown.org Fan fiction 0.73
23 apple.com Technology 0.75
24 dell.com Technology 0.77
25 sharepoint.com Technology 0.83


How Each Website’s Carbon Footprint Was Calculated

To estimate each site’s impact on the planet, Uswitch used a carbon calculator called Website Carbon to compare the carbon emissions of more than 200 of the world’s most popular websites.

The sustainability tool works out the amount of energy that’s used when someone loads a page on a website – this factors in the energy that’s required at the data centre (the cloud), by the telecoms network and by the user’s computer or mobile, as well as things like whether the data centre is using green energy to power it.

With more and more of us are making changes to minimise our impact on the planet and to live more sustainably, but even some of the most environmentally conscious people might not be aware that our personal carbon footprint is also impacted by our virtual lives too.

How Different Online Industries Impact The Planet

The report also looked into specific industries to discover which sites were the best and worst in their field.

When it comes to fashion, Victoria’s Secret is the worst website for carbon emissions, with 6.64g of CO2 produced with every visit to the site. Mazda is last place in the automotive pack with an estimated 16.19g of CO2 emitted every time someone loads the website and, in the beauty industry, Urban Decay is the ‘dirtiest’ website, producing 11.29 of CO2 from every visit to the site.


Top 5 Dirtiest Websites, by industry

  Website Amount of carbon per website visit
1 victoriassecret.com 6.64
2 nastygal.com 5.67
3 uniqlo.com 5.22
4 footasylum.com 3.35
5 everything5pounds.com 3.24

  Website Amount of carbon per website visit
1 mazda.co.uk 16.19
2 jeep.co.uk 10.73
3 mitsubishi-motors.co.uk 10.07
4 kia.com 7.08
5 subaru.co.uk 4.27


  Website Amount of carbon per website visit
1 clinique.co.uk 9.63
2 trinnylondon.com 4.85
3 elfcosmetics.co.uk 4.3
4 lookfantastic.com 3.75
5 aesop.com 3.6


With much of the UK and the world still working from home, the research team also compared some of the tools that have helped with remote working recently. Given Dropbox is in the game of data storage, it’s perhaps unsurprising it’s the worst website for carbon emissions, with a visit to the site emitting 7.35g of CO2.

When comparing different travel companies, although most brands performed better than a lot of the other companies in different industries, it’s Qatar Airways’ site that’s revealed as the most carbon emitting, with 3.16g produced with every visit.

In the streaming and gaming industry, it’s the third ‘dirtiest’ website overall, Nintendo that takes the top spot for the worst streaming and gaming site for carbon emissions, with 11.43g of CO2 produced every time someone visits the site.

  Website Amount of carbon per website visit
1 dropbox.com 7.35
2 slack.com 4.72
3 zoom.us 4.3
4 asana.com 3.95
5 office.com 2.26


  Website Amount of carbon per website visit
1 qatarairways.com 3.16
2 sykescottages.co.uk 2.89
3 easyjet.com 2.4
4 expedia.com 2.1
5 skyscanner.net 1.7


Streaming and gaming
  Website Amount of carbon per website visit
1 nintendo.com 11.43
2 store.steampowered.com 3.52
3 sky.com 3.45
4 playstation.com 3.13
5 stadia.google.com 2.78

Carbon expert, Tom Greenwood from Website Carbon commented:

Improving energy efficiency and prioritising renewable energy sources are two key ways a website can reduce its carbon emissions. A good place to start is making sure the size of images, fonts and videos are kept to an absolute minimum – this will reduce the amount of data that needs to be transferred when someone uses the site, and will in turn reduce the amount of energy used. Reducing website emissions might sound a bit niche, but there’s a stack of other benefits for the customer as well as the company – from improved user experience, to better security, better accessibility and faster load times. So, it’s a win-win for people and planet.”

To find out more about the world’s best and worst sites for carbon emissions and to find out easy ways to reduce your digital carbon footprint, visit https://www.uswitch.com/gas-electricity/worlds-dirtiest-websites/

By Jim O Brien/CEO

CEO and expert in transport and Mobile tech. A fan 20 years, mobile consultant, Nokia Mobile expert, Former Nokia/Microsoft VIP,Multiple forum tech supporter with worldwide top ranking,Working in the background on mobile technology, Weekly radio show, Featured on the RTE consumer show, Cavan TV and on TRT WORLD. Award winning Technology reviewer and blogger. Security and logisitcs Professional.

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