Digital technology: an industry with a colossal carbon footprint
We often imagine the digital industry as clean, immaterial, with no visible smoke or waste. The reality is quite different. The global digital sector is responsible for approximately 3.5 to 4% of worldwide greenhouse gas emissions — roughly the same as international air transport, or even more depending on the calculation methodology used. And unlike many sectors, this footprint continues to grow: it could double by 2030 if nothing is done.
In France, ADEME and ARCEP published a landmark study in 2023 estimating the carbon footprint of the French digital sector at 17.4 million tonnes of CO₂ equivalent per year, or about 2.5% of the total national footprint. This figure puts the digital sector on par with French domestic aviation.
Where does the digital carbon footprint come from?
Device manufacturing: the dominant factor
Contrary to what one might think, the largest share of the digital carbon footprint does not come from using devices, but from their manufacturing. For a smartphone, production accounts for 80 to 85% of its total footprint over its lifetime. For a laptop, it is around 70%.
Why? Because the manufacture of electronic components — processors, memory, screens — is extremely energy-intensive and requires rare mineral resources (cobalt, lithium, rare earths) whose extraction is itself highly impactful.
- Smartphone: 60 to 80 kg of CO₂e for manufacturing
- Laptop: 300 to 400 kg of CO₂e
- Desktop computer + monitor: 500 to 700 kg of CO₂e
- Television: 400 to 600 kg of CO₂e depending on size
Data centers: the energy behemoths
Data centers house the servers that power the internet: websites, applications, cloud services, streaming, email. Globally, data centers consume approximately 200 to 250 TWh of electricity per year, roughly 1% of global consumption. In France, they account for about 3% of national electricity consumption, and their usage grows by 5 to 10% annually.
The relatively good news: many data center operators (Google, Microsoft, Amazon) are increasingly sourcing renewable energy and improving their energy efficiency (PUE — Power Usage Effectiveness). The bad news: demand is growing faster than efficiency gains.
Networks: the invisible infrastructure
Telecommunications networks (fiber, 4G/5G antennas, undersea cables, network equipment) consume roughly as much energy as data centers. 5G, while more performant, is paradoxically more energy-hungry per antenna than 4G — even though it is more efficient per gigabyte transmitted. The massive rollout of 5G is expected to significantly increase network energy consumption by 2025-2030.
The most impactful uses
Video streaming: the data heavyweight
Online video alone accounts for 82% of global internet traffic (Cisco, 2022) and approximately 1% of global CO₂ emissions. Netflix alone generates about 0.08 kg of CO₂ per hour of HD viewing. Multiplied by 240 million subscribers watching an average of 2 hours per day, the numbers become staggering.
An important nuance: the footprint of streaming depends heavily on the network used. WiFi emits about 10 times less than 4G to transmit the same volume of data. Watching a series over 4G produces about 4 times more emissions than the same content over WiFi.
Emails: a drop in the ocean, but symbolic
A simple email emits about 4 grams of CO₂. An email with a large attachment can reach 50 grams. These figures seem tiny, but at a global scale — 300 billion emails sent every day — they add up to significant emissions.
More importantly: spam accounts for 85% of global email traffic and a considerable, entirely useless carbon footprint. Unsubscribing from unwanted newsletters is therefore a real gesture (even if a modest one).
Cloud and storage
Every file stored in the cloud — photo, document, video — permanently occupies space on servers running 24/7. The amount of data stored worldwide doubles every two years. Regularly cleaning up your cloud storage and deleting unnecessary data is a digital hygiene habit worth taking seriously.
Bitcoin and cryptocurrencies
Bitcoin mining is an extraordinarily energy-intensive activity. In 2022, the Bitcoin network consumed more electricity than Finland — approximately 120 TWh per year. Its carbon footprint is estimated at 65 million tonnes of CO₂ per year, as much as the entire country of Greece.
How to reduce your digital carbon footprint?
High-impact actions
- Keep your devices as long as possible: this is the most effective action. Going from 2 to 4 years of smartphone use cuts its annual footprint by 50%.
- Buy refurbished: a refurbished smartphone emits 70 to 80% less CO₂ at purchase than an equivalent new model.
- Repair rather than replace: the repairability index, mandatory in France since 2021, helps you choose durable devices.
Medium-impact actions
- Prefer WiFi over 4G/5G: for intensive use (streaming, downloads), WiFi consumes 10 times less network energy.
- Reduce streaming quality: switching from 4K to HD reduces data consumption by 75% without noticeable degradation on a standard screen.
- Turn off devices rather than leaving them on standby: an internet router on standby consumes almost as much as in normal operation.
- Clean up your cloud storage: delete duplicate photos, old backups, and large attachments.
Low-impact but symbolically useful actions
- Unsubscribe from useless newsletters
- Delete unused applications
- Choose a less energy-intensive search engine (Ecosia, which plants trees)
- Use dark mode (saves energy on OLED screens)
For practical tips on your overall daily carbon footprint, see our complete guide: 15 practical steps to reduce your daily carbon footprint.
Generative AI: the new threat to the digital carbon footprint
The meteoric rise of generative artificial intelligence (ChatGPT, Gemini, Midjourney) is upending the energy equation of the digital sector. A ChatGPT query consumes approximately 10 times more energy than a standard Google search. Microsoft announced that its CO₂ emissions increased by 29% between 2020 and 2023, primarily due to AI. Google saw its emissions rise by 48% over the same period.
This trend is concerning because it risks canceling out progress made elsewhere in data center energy efficiency.
Calculating your own digital footprint
Several tools allow you to assess the footprint of your digital habits:
- GreenIT-Analysis: a browser extension that measures the impact of the web pages you visit
- Carbonalyser: a Firefox extension that measures the energy consumption of your browsing in real time
- Nos Gestes Climat (ADEME): includes a digital module in its general calculator
To calculate your entire personal carbon footprint, including your digital usage, read our article: How to calculate your personal carbon footprint.
Conclusion: digital sobriety, a forward-looking choice
Digital sobriety does not mean giving up technological progress, but adopting a more conscious and thoughtful relationship with our usage. Extending the lifespan of our devices, reducing the most energy-intensive uses, and supporting energy efficiency policies for data centers are levers within everyone's reach. In a sector whose emissions could double by 2030, every action counts.