www.yale.edu

The numbers

First visit

0.249 g CO₂e

Return visit

0.0047 g CO₂e

Hosting

unknown

LCP

416 ms

CLS

0.004

TTFB

35 ms

At 10,000 views a month this page emits about 22.5 kg CO₂e a year, roughly 92 km in an average petrol car. The estimate assumes 75% new and 25% returning visitors, a measured cache reload ratio of 2%, and world-average grid intensity. How we calculate this

1. Audit third-party servicessave ~0.030 g/visit (272 kB)High impact · moderate effort

   9 third-party domains account for 544 kB (32% 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.

   • www.googletagmanager.com419 kB
   • siteimproveanalytics.com41 kB
   • ajax.googleapis.com34 kB
   • www.google-analytics.com21 kB
   • js-agent.newrelic.com20 kB
   • maxcdn.bootstrapcdn.com7.5 kB

   WSG 3.5: Treat third parties the same as first parties
2. Reduce JavaScript payloadsave ~0.022 g/visit (193 kB)High impact · moderate effort

   17 scripts total 771 kB on the wire (2.18 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.

   • js164 kB
   • gtm.js130 kB
   • js124 kB
   • js97 kB
   • site.js75 kB

   WSG 3.2: Minify and remove unused codeWSG 3.3: Modularize bandwidth-heavy components
3. Optimize web fontssave ~0.026 g/visit (235 kB)Medium impact · quick fix

   6 font files total 408 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.

   • Mallory-LightItalic.woff78 kB
   • Mallory-Bold.woff77 kB
   • Mallory-Medium.woff77 kB
   • Mallory-Light.woff74 kB
   • fontawesome-webfont.woff272 kB

   WSG 2.11: Use optimized web typography
4. Lazy-load below-the-fold mediasave ~0.019 g/visit (168 kB)Medium impact · quick fix

   12 below-the-fold images/iframes (335 kB) 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.

   • 7743dc7e-bbcb-4a78-834a-4055133234a8.jpg68 kB
   • 2011_07_12_01-07-06_dsc_0311_1_1.jpg59 kB
   • hora_mountain_from_afar_jacob_davis-yn_copy.png36 kB
   • vangogh_-12507-002.jpg32 kB
   • 2-aegueicxtjcwehtbjx6qkd31goorbvsrar0pkzbuq_0…28 kB

   WSG 2.9: Optimize media to reduce resource use
5. 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
6. Upgrade compression beyond gzipsave ~0.0074 g/visit (66 kB)Advisory · quick fix

   443 kB 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.

   • js97 kB
   • site.js75 kB
   • site.css61 kB
   • siteanalyze_66356571.js41 kB
   • jquery.min.js34 kB

   WSG 4.3: Reduce data transfer with compression
7. Remove the entry redirectAdvisory · quick fix

   The address that was scanned goes through 1 redirect before the document is served, ending at https://www.yale.edu/. Every hop is a full round trip on a connection that has not warmed up yet.

   Point links, sitemaps and canonical tags at the final address, and make the host redirect in one hop rather than chaining http to https to www.

   • https://yale.edu/redirects to https://www.yale.edu/

   WSG 4.4: Setup necessary error pages and redirection links

Where the bytes are

• JavaScript771 kB · 17 req
• Fonts408 kB · 6 req
• Images385 kB · 19 req
• CSS84 kB · 12 req
• HTML30 kB · 1 req
• Data (XHR)1.2 kB · 2 req
• Data (fetch)0 B · 1 req