Sustainability Scores in Design Systems

In 2025, digital sustainability is a business KPI. The 'Digital Carbon Footprint' is part of ESG reporting for major companies. Because the internet consumes more electricity than entire countries – and designers can do something about it.

• Internet power consumption: 416 TWh/year (more than UK)
• CO₂ per page view: 1.76g (average)
• 1 video stream (HD, 1h): ~36g CO₂
• Global ICT emissions: 2-4% (more than aviation!)
• Projected 2030: 8% of all global emissions

| Factor | Share | Influenced by Design | |--------|-------|---------------------| | Data centers | 15% | Medium (image sizes, caching) | | Networks | 20% | High (data volume) | | End devices | 65% | High (rendering, CPU load) |

• Black pixels = off pixels on OLED
• Energy savings: up to 60% with dark UIs
• Apple & Google recommend 'Dark First'

• 1 Variable Font = 10+ static variants
• Savings: ~100KB per page
• Roboto Flex: 1 file instead of 18

• AVIF: 50% smaller than WebP, 80% smaller than JPEG
• At same quality
• Browser support 2025: >95%

• Images, videos, iframes: Only load when visible
• `loading='lazy'` – one HTML attribute, big impact

• Video autoplay: 100x more data than still image
• Click-to-Play reduces data usage by 90%+

• -apple-system, BlinkMacSystemFont, 'Segoe UI'...
• 0 KB download, perfect rendering

• Icon font: ~50KB
• 20 SVG icons inline: ~5KB

• `@media (prefers-reduced-motion: reduce)`
• Less animation = less CPU = less energy

• Every component has a 'performance budget'
• Max. 50KB JavaScript per feature
• Lighthouse score as acceptance criterion

• Automatically resource-saving variant when:
• • Low battery
• • Poor connection
• • 'Data Saver' activated

• Server farms with 100% renewables
• Minimalist UI without tracking
• ~4g CO₂ per search (vs. 7g for Google)
• 200+ million trees planted

• 'This website runs on green power'
• The Green Web Foundation certification

• 'This order causes Xg CO₂'
• 'Offset for $0.50?'
• Patagonia: +23% offset opt-ins

• Faster pages = better conversion
• Walmart: +2% conversion per 1 second load time
• Google: Page Speed is ranking factor
• Sustainability as brand promise (Gen Z!)

Sustainability is no longer a compromise – it's a quality feature.