The internet and cloud computing are often perceived as "immaterial" and therefore "green." In reality, the physical infrastructure supporting the internet — data centers, communication networks, and user devices — consumes enormous amounts of energy. The ICT sector (Information and Communications Technology) is responsible for roughly 4% of global greenhouse gas emissions, with projections that could push it to 8–14% by 2030 without energy efficiency and decarbonization measures. This percentage already exceeds global commercial aviation (about 2.5% of emissions).

The Carbon Footprint of Major Digital Services

Not all digital services have the same footprint. Estimates based on typical usage by a European adult. HD video streaming (Netflix, YouTube, Disney+): approximately 36 g CO2eq per hour of streaming on TV (the network and data centers: a 30–40% reduction compared to earlier estimates according to Shift Project's 2020 revision). Kamiya's research (IEA, 2022) has scaled back the more alarming estimates from previous years. Standard email (without attachments): 0.3–4 g CO2eq per email. An email with a heavy attachment: 50 g CO2eq. One hour of video conferencing (Teams, Zoom, Google Meet): 150–1,000 g CO2eq depending on video quality. Turning off your camera reduces the video conference footprint by 96%. Google search: approximately 0.2 g CO2eq per search (Google's 2023 update: efficiency has improved significantly in recent years). Social media post with photo: approximately 0.2–0.5 g CO2eq per post (varies by platform and image quality). Bitcoin crypto mining: the Bitcoin blockchain consumes roughly 150 TWh per year (more than Argentina, according to Cambridge Centre for Alternative Finance 2023) — enormously higher than any other digital service.

Data Centers: The Heart of Internet Energy Consumption

Data centers consume roughly 40–45% of the total energy used by the ICT sector. A large hyperscaler data center (Google, Microsoft, Amazon) can consume 100–200 MW of electrical power — equivalent to a small power plant. The main drivers of consumption: cooling systems (40% of consumption goes to server cooling), servers (the actual computing power), uninterruptible power supply (UPS) systems, and lighting. Data center efficiency is measured by PUE (Power Usage Effectiveness): the ratio of total energy consumed to energy actually used for computing. A PUE of 1.0 is theoretically perfect (no losses). Traditional data centers have a PUE of 1.5–2.0. Major hyperscalers have achieved a PUE of 1.1–1.2, much more efficient. Google reports a global average PUE of 1.10 (2022), among the best in the world. Cooling innovations: direct liquid cooling (servers are immersed in dielectric liquids or cooled with liquid heat exchangers), sites in cold zones (Microsoft's data centers in Ireland, Google's in Finland, Meta's in Luleå, Sweden take advantage of cold climates to reduce active cooling requirements).

Major Providers' Commitments to Decarbonization

The leading hyperscalers have announced ambitious decarbonization targets: Google: 100% renewable energy since 2017 (on a global annual basis), with the goal of operating on 100% carbon-free energy on an hourly basis (not just annually) by 2030. Microsoft: carbon negative by 2030 (will remove more CO2 than it emits), zero carbon by 2050. Amazon Web Services: net-zero carbon by 2040, 100% renewable energy by 2025. Apple: all global operations already powered 100% by renewables, with the goal of carbon-neutral supply chain and products by 2030. How to verify: the annual sustainability reports from these providers are public and verifiable. The main criticism: many of these targets rely on Renewable Energy Credits (RECs) that don't guarantee the energy consumed by the data center is physically produced by renewables at the same time and place. Google is the only one explicitly targeting hourly matching (24/7 carbon-free energy): the most rigorous standard.

How to Reduce Your Digital Footprint

Actions with the greatest impact: turn off your camera during video conferences when not necessary (96% reduction in the conference footprint), choose the lowest video quality appropriate for your use (720p instead of 4K for laptop videos: 70–80% reduction in data traffic), reduce background video streaming (don't leave YouTube open for music: use a music app with compressed audio signal), use dark mode on OLED devices (reduces display consumption by 20–60% for black pixels), clean out your email inbox by deleting old emails with attachments (servers store everything: every email is an energy cost for hosting), prefer downloading to streaming for content you use frequently (watching a movie locally instead of streaming it each time saves repeated data traffic).

Choosing More Sustainable Cloud Services: A Practical Guide

Not all cloud providers are equally sustainable. How to evaluate them: check the provider's renewable energy rate (reported in annual sustainability reports), review the PUE of their data centers (lower is better), prefer providers using liquid cooling or Nordic locations, look for environmental certifications (ISO 14001, Green Star rating for data centers). Cloud providers with the best sustainability performance: Google Cloud (leader for 24/7 carbon-free energy in advanced regions), Microsoft Azure (solid commitments, specific high-renewable regions), AWS (improving but with more delays compared to Google and Microsoft). Alternative European providers with a sustainability focus: OVHcloud (France, data centers with water cooling), Hetzner (Germany, data centers powered by renewables), Infomaniak (Switzerland, 100% renewables, ecological certification). For individuals and small businesses: the choice of cloud provider has marginal impact compared to digital behavior choices. For large companies with significant cloud infrastructure: the choice of provider and geographic location of the cloud can reduce ICT footprint by 30–70%.

Jevons Paradox Applied to Digital

Jevons Paradox (or rebound effect) describes the phenomenon where improvements in a technology's efficiency lead to an increase in its total consumption instead of the expected reduction. Applied to digital: data centers become increasingly efficient, but the volume of data processed grows even faster (global internet traffic roughly doubles every 3 years). Efficiency per GB has improved enormously, but total GB has grown even more: net result = greater absolute consumption. This paradox is relevant to digital energy policy: improving server efficiency isn't enough; you also need to manage data growth (video resolution, audio quality, unnecessary metadata) and ensure additional energy comes from renewables. The key is decarbonizing electricity production, not just improving device efficiency.

The Sustainable Website: How to Measure It

Website design choices also influence the carbon footprint of the digital world. A heavy website (with unoptimized high-resolution images, autoplay videos, heavy JavaScript scripts) requires more data transmission and more processing on the user's device, therefore more energy. How to measure a website's carbon footprint: Website Carbon Calculator (websitecarbon.com): estimates emissions per visit for any public website. Ecograder (ecograder.com): evaluates your site on energy efficiency, performance, green hosting, and UX. How to reduce a website's footprint: optimize images (WebP format instead of JPEG/PNG: smaller files, same quality), reduce non-essential JavaScript scripts, use lazy loading (load images only when viewed), choose a hosting provider powered 100% by renewables (Green Web Foundation certifies green providers: thegreenwebfoundation.org), avoid autoplay videos. For blogs and editorial sites: every published article is perpetual hosting: removing outdated content reduces hosting energy.