Consumption and emissions belong together – just like cause and effect. If consumption goes up, the footprint gets bigger. If awareness goes up, action will follow. Expectations are evolving. So we raise awareness.
Websites come to life in the user's browser – not on the server. The server only delivers the building blocks. How a page actually looks, behaves and performs is determined in the browser. Anyone testing only on the server is checking the plan, not the result. Whether a page truly works becomes visible on the screen where it appears. That's where we look.
The average web page has grown 100× heavier in 20 years. Every unnecessary kilobyte costs conversion rates, Core Web Vitals scores, hosting bandwidth, and CO₂ emissions.
Images account for over 50% of page weight on most websites. When served in the wrong format (JPEG instead of WebP/AVIF) or at the wrong size, the page loads noticeably slower. The Largest Contentful Paint — a key Google ranking factor — suffers directly. For users, this means waiting. For operators: fewer conversions and higher hosting costs.
Without compression (gzip or Brotli), HTML, CSS, and JavaScript are transferred at full size — 60 to 80% larger than necessary. It is like sending a letter without an envelope: the content is the same, but transport costs several times more. Every page view wastes bandwidth, energy, and therefore CO₂.
Analytics, chat widgets, tracking pixels, A/B testing tools — each embedded script loads additional code, opens network connections, and blocks page rendering. Many of these scripts were introduced once and never removed. They cost performance, generate CO₂, and often raise additional privacy concerns.
Without correct cache headers, the browser re-downloads all resources on every visit — even when nothing has changed. This strains the server, slows the page for returning visitors, and wastes energy on both ends of the connection.
Images that only become visible on scroll should only be loaded then. Without lazy loading, the browser loads all images at once — including those the user may never see. This slows the initial page load and wastes bandwidth.
When CSS and JavaScript files block page rendering, the user sees a white screen until everything has loaded. The more blocking resources, the longer the wait. Google measures this via Time to Interactive — a slow page means worse rankings and higher bounce rates.
A website's carbon footprint depends not only on its weight, but also on where the data center's electricity comes from. Hosting on renewable energy can reduce CO₂ output by 80-90%. For companies with ESG commitments or CSRD reporting obligations, green hosting is a concrete, measurable lever.
Every single HTTP request — whether image, script, stylesheet, or font — costs time and energy. A page with over 100 requests strains server, network, and device significantly more than one with 30. Fewer requests mean faster load times, less energy consumption, and a smaller carbon footprint.
Common questions about website carbon footprint and sustainability.