qwen.ai/blog?id=qwen3.8

The numbers

First visit

0.728 g CO₂e

Return visit

0.030 g CO₂e

Hosting

unknown

LCP

1.45 s

CLS

0.097

TTFB

182 ms

At 10,000 views a month this page emits about 66.4 kg CO₂e a year, roughly 272 km in an average petrol car. The estimate assumes 75% new and 25% returning visitors, a measured cache reload ratio of 4%, and world-average grid intensity. How we calculate this

1. Audit third-party servicessave ~0.270 g/visit (2.40 MB)High impact · moderate effort

   17 third-party domains account for 4.80 MB (98% of the page).

   Remove services that no longer earn their place; load the rest on interaction (facades for embeds, delayed consent-gated tags). Each third party is also a privacy and performance dependency.

   • qianwen-res.oss-cn-beijing.aliyuncs.com1.52 MB
   • g.alicdn.com1.19 MB
   • img.alicdn.com898 kB
   • docs.qwenlm.ai381 kB
   • cdn.jsdelivr.net372 kB
   • gstatic.loli.net107 kB

   WSG 3.5: Treat third parties the same as first parties
2. Convert and compress imagessave ~0.100 g/visit (883 kB)High impact · quick fix

   12 images (1.61 MB) ship in legacy formats (JPEG/PNG/GIF); 1 image exceeds 300 kB apiece.

   Serve AVIF (or WebP) with responsive srcset sizes, and re-compress oversized files. AVIF typically halves JPEG weight at the same visual quality.

   • performance.png1.21 MB
   • O1CN01TOLJZy7eq7E5aQk4_!!6000000000033-2-tps-…470 kB
   • harness-generalization-3.8.png158 kB
   • training-score-vs-envs-scale.png155 kB
   • logo.png83 kB

   WSG 2.9: Optimize media to reduce resource use
3. Reduce JavaScript payloadsave ~0.031 g/visit (274 kB)High impact · moderate effort

   40 scripts total 1.10 MB on the wire (3.62 MB decoded). Bundles this size usually carry a lot of unused code.

   Split bundles per route, tree-shake dependencies, and audit with a bundle analyzer or coverage profile. A 25% cut is a conservative target for bundles this size.

   • 9509.js131 kB
   • et_f.js112 kB
   • 2766.js105 kB
   • b3cb5cc6.js78 kB
   • eee9d9dd.js78 kB

   WSG 3.2: Minify and remove unused codeWSG 3.3: Modularize bandwidth-heavy components
4. Lazy-load below-the-fold mediasave ~0.0074 g/visit (66 kB)High impact · quick fix

   8 below-the-fold images/iframes (1.22 MB) download immediately for every visitor.

   Add loading="lazy" to below-fold img and iframe elements (and keep it off the LCP image). Browsers then fetch them only when scrolling approaches.

   • performance.png1.21 MB
   • O1CN01OwlzsC1cRTnZrFfXa_!!6000000003597-2-tps…2.9 kB
   • O1CN01DJfj2R28G5Z6O677U_!!6000000007904-2-tps…1.6 kB
   • O1CN01696apl1pyzhNJ40bg_!!6000000005430-2-tps…1.4 kB
   • O1CN01LF6pFa1PE79GHDehi_!!6000000001808-2-tps…1.2 kB

   WSG 2.9: Optimize media to reduce resource use
5. Optimize web fontssave ~0.029 g/visit (261 kB)Medium impact · quick fix

   12 font files total 587 kB, 4 not in WOFF2.

   Subset fonts to used glyphs, prefer one variable font over multiple weights, serve WOFF2 only, and consider system fonts for UI text.

   • Roboto-BoldItalic.ttf95 kB
   • Roboto-Italic.ttf95 kB
   • Roboto-Bold.ttf89 kB
   • Roboto-Regular.ttf89 kB
   • font_4808287_y5yts1vlc7q.woff258 kB

   WSG 2.11: Use optimized web typography
6. Fix caching for returning visitorssave ~0.0046 g/visit (31 kB)Medium impact · quick fix

   On a repeat visit 123 kB of static assets were re-downloaded instead of coming from cache.

   Serve static assets with Cache-Control: public, max-age=31536000, immutable and versioned filenames so returning visitors download almost nothing.

   • db54c4fbbb70811a.mp4no Cache-Control header · 46 kB
   • stylesheet.310efffca058470270cf97873a2d9dbce2…no Cache-Control header · 28 kB
   • 9gD33bvv2spA4mCSNno Cache-Control header · 24 kB
   • 4cVZN2Vn2iIs9IJBjOq+XKY4LEnabImko5lgcRiS57xwY…no Cache-Control header · 24 kB
   • index.jsCache-Control: max-age=15,s-maxage=3600 · 497 B

   WSG 4.2: Optimize caching and support offline access
7. Defer video and audiosave ~0.0026 g/visit (23 kB)Medium impact · quick fix

   6 videos preload data without preload="none".

   Never autoload media: use preload="none" with a poster image, load players on interaction, and stream in an efficient codec (AV1/HEVC).

   • db54c4fbbb70811a.mp446 kB
   • G8A_8_CruafTxUNTh9MrBNmKmI9mScSBKfY3WH--asg.mp40 B
   • 1h6qXKSnAjXp6lHfSDX1xfKukA0Y5hUUQ73qqUtY4aQ.mp40 B
   • g1Iouht-8GIF-k6peB4RPgL0xYvGf6OK_THgInrMdb4.mp40 B
   • 3lqSB8ahF_uFyftvfwYyHG2HTv0XmGsSWTbPjSLlbwg.mp40 B

   WSG 2.9: Optimize media to reduce resource use
8. Serve images at the size they displayMedium impact · quick fix

   1 image is encoded at more than twice the pixels the layout shows, even accounting for this viewport's pixel density.

   Generate multiple sizes and let the browser pick with srcset/sizes; a 4000px original behind a 400px slot spends bandwidth no screen displays.

   • performance.png1.21 MB

   WSG 2.9: Optimize media to reduce resource use
9. Verify your hosting energyMedium impact · moderate effort

   This host has not published renewable energy evidence with the Green Web Foundation, so its energy source is unknown.

   Choose a provider listed in the Green Web Directory, or ask your current provider to publish evidence (and a carbon.txt). This cuts the data-center share of every single page view.

   • carbon.txtNo carbon.txt found at the site root; publishing one is the lightest first step.

   WSG 4.1: Use sustainable hosting
10. Upgrade compression beyond gzipsave ~0.030 g/visit (264 kB)Advisory · quick fix

    1.76 MB of text ships gzip-compressed; Brotli or Zstandard would cut roughly another 15-20%, and browsers without them fall back to gzip automatically.

    Serve precompressed Brotli for static text assets (highest level, compressed at build time) and enable Brotli or zstd for dynamic responses; keep gzip only as the fallback.

    • QfeH4_www2025_animation_v5_1.html315 kB
    • 9509.js131 kB
    • et_f.js112 kB
    • 2766.js105 kB
    • 2766.css78 kB

    WSG 4.3: Reduce data transfer with compression
11. Set a page-weight budgetAdvisory · moderate effort

    At 4.91 MB per view this page rates F. The findings above list where the weight is.

    Agree a transfer budget (e.g. under 975 kB reaches a B), enforce it in CI, and re-scan after each change to hold the line.

    WSG 3.1: Set goals based on performance and energy impact
12. Simplify the document structureAdvisory · larger effort

    The page renders 2552 DOM elements, above the 1,500 guideline. Large trees cost memory and CPU on every visitor's device.

    Flatten wrapper markup, render long lists virtually or paginate, and prefer semantic elements over nested divs.

    WSG 3.6: Ensure code follows good semantic practices
13. Upgrade connections to HTTP/2 or HTTP/3Advisory · quick fix

    1 host serves five or more resources over HTTP/1.1, paying per-request connection and header overhead newer protocols eliminate.

    Enable HTTP/2 (or HTTP/3) on the server or move the assets behind a CDN that speaks it; multiplexing makes many small requests nearly free.

    • aplus.qwen.ai5 requests over http/1.1

    WSG 3.1: Set goals based on performance and energy impact

Where the bytes are

• Images2.51 MB · 35 req
• JavaScript1.10 MB · 40 req
• Fonts587 kB · 12 req
• HTML409 kB · 3 req
• CSS151 kB · 13 req
• Data (fetch)64 kB · 2 req
• Data (XHR)48 kB · 3 req
• Audio / video46 kB · 8 req
• Other2.8 kB · 5 req