Decarbonizing the Internet: Understanding and Reducing Internet CO2 Emissions

Written by Project Analyst Rob Hewitt.

Did you know that using the internet generates 229 kilograms of CO₂ per person each year—roughly the same as burning 97 litres of gasoline? While it might not be as visible as car exhaust, our daily online habits have a real impact on the planet. While the emissions may be less apparent in day-to-day life than the tailpipe emissions from a fossil fuel-powered vehicle, the internet has a considerable global carbon footprint due to the continuous need for electricity. From the smartwatch to the network cell tower to the data centre, the entire internet ecosystem demands electricity to fulfill the end-user’s requests. With the internet now playing a vital role in many people’s everyday lives, the constant call for power from the internet is only expected to grow. To foster sustainable internet use, we must first understand how internet use generates GHG emissions, how we measure them, and how we can ultimately reduce them.  

How Browsing Produces CO₂ Emissions

Picture a typical workday for an office employee. The morning may start with several minutes spent scrolling through social media and news apps on their phone before work. While riding transit to the office, their phone streams a podcast, and they answer personal emails. Once at work, the day consists of video conference calls, scrolling through web pages and articles, and responding to more emails. After work, while at home, a TV series streams in the background, and a cooking video plays on the phone as dinner is being prepared.  

Every one of these seemingly routine activities throughout the day required the internet. While inherently small, this constant internet connectivity requires energy to facilitate data flow to and from the end-user’s device. When viewed individually, the emissions from these activities are small, but when multiplied by the fact that most of the world uses the internet every day, the demand for energy and the resulting emissions suddenly become much more significant.  

The scenario above details the operational emissions of a digital footprint, which describes the act of using the internet. However, these are only part of the equation for calculating digital emissions. When considering the full impact of digital browsing, the emissions associated with the production of devices, networks, and data centers used to carry out these activities must also be taken into account. These are called embodied emissions, and they account for the energy and materials required to manufacture the equipment and systems used when accessing the internet. 

Combined, the impact from both the operational and embodied emissions from the Information and Communication Technology sector accounted for 1.8% – 2.8% of the world’s human-related emissions in 2020. This is equivalent to 1.0-1.7 gigatonnes of CO₂e or the emissions from 1.1 billion passenger vehicles. 

Measuring Internet CO₂ Emissions: The SWDM Approach

Now that we understand the source of digital emissions, effectively managing them requires measuring them. By measuring the emissions, a baseline value is established, which can be used to track the effectiveness and progress of sustainable actions. As described above, there are two components to digital emissions: operational and embodied. We know that electricity consumption generates operational emissions, as energy is required for digital systems to remain active. However, without access to individualized energy demand tracking for all components of a digital system, how can emissions be accurately calculated if we don’t know the exact amount of electricity consumed? 

Developed by the World Wide Web Consortium, the Sustainable Web Design Model (SWDM) is an attempt to address this challenge by employing a top-down approach to electricity consumption. This enables users of the model to estimate electricity consumption using a standard conversion factor. Think of the SWDM as a way to translate all the energy used online into a simple, understandable number—like how much CO₂ your browsing creates. 

How it works: The SWDM first determines the total energy demand from the digital world over a one-year period. To do so, the SWDM utilizes information from the International Energy Agency, which publishes energy demand data for data centers, networks, and end-users. To translate the total energy consumed by each digital system into an individual activity or user, the SWDM evaluates the amount of “work” or output produced by the digital world from the total energy consumed. For simplicity, the metric chosen by SWDM is the amount of data in gigabytes transferred across the internet. With this metric of total energy consumed by the digital world per the total data transferred by the digital world (kWh/GB,) the model can now be used to compare individual activities across digital systems. To measure the embodied emissions, the same top-down approach is followed; however, the global energy required to produce data centers, networks, and end-user devices is applied to the total data transferred by the digital world. Displayed below is a simplified version of the SWDM formula. To fully account for digital emissions, the model also considers other factors, such as return and new visitor ratios, data cache ratios, and green hosting. Based on this approach, it is clear that activities requiring more data to be transferred, such as high-resolution video, translate to increased energy consumption and ultimately more operational emissions. 

While the developers of the SWDM have noted that data transfer is not a perfect metric for equating digital activity to emissions, without an alternative that is accessible and consistent, data transfer remains the best option.  

Here’s a quick snapshot of how much energy different parts of the internet use per gigabyte of data. It helps put digital emissions into perspective. 

Digital Segment	Operational Energy Intensity (kWh/GB)	Embodied Energy Intensity (kWh/GB)
Data Centers (DC)	0.055	0.012
Network (N)	0.059	0.013
User Devices (UD)	0.080	0.081

Average Emissions per Page View (gCO₂e) = (OP_dc + EM_dc) + (OP_N + EM_N) + (OP_UD + EM_UD) 

• OP – Operational Emissions 

• EM – Embodied Emissions 

Ways to Reduce Your Digital CO₂ Emissions 

Now that we know where digital emissions come from, let’s explore how you can take action to reduce your own internet CO₂ footprint. 

Opportunities for reducing digital emissions exist across the digital landscape. Digital professionals and developers of apps, websites, and browsers may all play a role through intentional design. This can include streamlining code, lightweight webpages, and optimized media files. Elsewhere in the digital environment, data centers, which require a considerable supply of energy, should continue to be developed with access to renewable energy. Finally, as the end-user, intentional use of digital services can play a key role in reducing the overall energy consumption of your activity. Simple actions like those listed below do not restrict one’s access to the digital world but rather help to minimize the footprint of the activities: 

• Be mindful of streaming and cloud use – every little bit helps! 
  • Download rather than stream repeatedly 
  • Turn off auto-play or reduce video resolution 
  • Use carbon-neutral browsers like Shift 
• Clean your digital clutter 
  • Delete old emails, unsubscribe from lists, empty cloud trash 
  • Close apps and tabs 
• Manage Device Energy Consumption 
  • Turn on power saving modes 
  • Choose Dark mode or lower screen brightness – easier on your eyes, too. 
  • Unplug devices when not in use—you’re saving energy and your bill! 
• Upgrade at end-of-life 
  • Choose to repair and maintain devices rather than upgrading to the latest model – better for your wallet and the planet. 

Conclusion

Even though our daily internet use often feels invisible, it comes with a real environmental cost. The continuous electricity demands of data centers, networks, and devices mean that an average internet user generates 229 kilograms of CO₂e each year—roughly equivalent to burning 100 litres of gasoline. 

Accurately measuring digital emissions is the first step to decarbonizing internet use, and tools like the Sustainable Web Design Model (SWDM) help to estimate the full lifecycle emissions of digital systems, including data centers, networks, and user devices. With this information, we can make intentional choices to reduce our digital footprint. Organizations like Synergy have supported companies such as SHIFT by validating their Carbon Meter methodology against the Sustainable Web Design Model (SWDM) and by conducting a comprehensive Annual Greenhouse Gas Inventory, including Category 11 emissions from digital products.

Decarbonization is a shared responsibility. Users can make mindful choices about streaming and device use, developers can optimize apps and websites, and infrastructure operators can transition to renewable energy. By taking intentional steps across the digital ecosystem, we can collectively reduce the internet’s electricity demand and lower its carbon impact.
 

Curious about your own digital footprint? Measure your company’s internet CO₂ emissions and explore practical ways to reduce them. Book a free 30-minute exploration call to get personalized guidance. 

Want to learn how Shift partnered with Synergy to become one of the first browsers to offer carbon-neutral browsing, using the Sustainable Web Design Model? Read the Case Study.

 

References

Freitag, C., Berners-Lee, M., Widdicks, K., Knowles, B., Blair, G. S., & Friday, A. (2021). The real climate and transformative impact of ICT: A critique of estimates, trends, and regulations. Patterns, 2(9), 100340.https://www.sciencedirect.com/science/article/pii/S2666389921001884 

Sustainable Web Design. (2025). Home – Sustainable web design.https://sustainablewebdesign.org/ 

Natural Resources Canada. (n.d.). Greenhouse gas equivalencies calculator. Government of Canada. https://oee.nrcan.gc.ca/corporate/statistics/neud/dpa/calculator/ghg-calculator.cfm