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https://uct.ac.za

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
57
GRADE
D
FIX
3
REVIEW
2
PASS
1
INFO
0
Device:
Mobile Desktop
Checks
6
1 PASS 2 REVIEW 3 FIX
F
CO2 Per Page Load
Action
2.94g CO2 per view
FIX
2.94g CO2 per view
Critical::
2.94g CO2 per page view
This page transfers 10.4 MB, producing an estimated 2.94g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.54g, network 0.51g, end-user device 1.89g.
Got: 2.94g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 352.7 kg CO2/year
With 10,000 page views per month, this page would generate approximately 352.7 kg of CO2 annually — equivalent to charging 44091 smartphones.

2.94g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 5% of websites

Sustainable Web Design model v4 · Page size: 10.4 MB

Your site
2.94g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.54g
Network
0.51g
End-user device
1.89g
At 10,000 monthly views: Monthly: 29.4 kg · Annual: 352.7 kg · ≈ 44091 smartphone charges
D
Green Hosting
Action
Not green
FIX
Not green
Info::
No confirmed renewable energy commitment detected
Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.
Info::
Green hosting status based on known provider commitments
Green hosting detection uses a curated database of provider renewable energy commitments. This is not a real-time verification. For authoritative checks, visit thegreenwebfoundation.org.
Green HostingNot Green Hosted
Hosting Not identified✗CDN Varnish✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

F
Carbon Budget
Action
95th percentile
FIX
95th percentile
Warning::
2.94g CO2 — above the median website (0.60g)
Heavier than an estimated 5% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 95th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

2.94g

95th percentile

Cleaner than 5% of websites

✗ Above the median website

vs Median 390% more
vs Target 488% more
B
Transfer Efficiency
89% efficient
REVIEW
89% efficient
Info::
Transfer efficiency: 89%
An estimated 1180 KB (11%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1180 KB of unused JavaScript. This wasted data produces 0.33g of unnecessary CO2 per page view.
89% efficient

Total waste: 1180 KB (11% of page weight)

Unused JS 1180 KB

0.33g unnecessary CO2 per visit

Actual transfer 10628 KB
Theoretical minimum 9447 KB
Potential savings 1180 KB (0.33g CO2)

See Deep Analysis sections above for specific optimizations.

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Repeat Visit Weight
97% cached
PASS
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 335 KB (vs 10628 KB first visit). 438 of 453 resources are served from browser cache, saving 2.85g CO2 per repeat visit.
Info::
Repeat visit: 0.09g CO2 (first visit: 2.94g)
First visit
10628 KB
Repeat visit
335 KB

97% reduction on repeat visits

Saving 2.85g CO2 per returning visitor

438 resources served from cache · 15 resources re-downloaded

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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