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https://royalsociety.org

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
78
GRADE
C
FIX
1
REVIEW
2
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
6
3 PASS 2 REVIEW 1 FIX
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 Microsoft IIS✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

B
Transfer Efficiency
88% efficient
REVIEW
88% efficient
Info::
Transfer efficiency: 88%
An estimated 164 KB (12%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 164 KB of unused JavaScript. This wasted data produces 0.05g of unnecessary CO2 per page view.
88% efficient

Total waste: 164 KB (12% of page weight)

Unused JS 164 KB

0.05g unnecessary CO2 per visit

Actual transfer 1430 KB
Theoretical minimum 1265 KB
Potential savings 164 KB (0.05g 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
CO2 Per Page Load
0.40g CO2 per view
PASS
0.40g CO2 per view
Info::
0.40g CO2 per page view
This page transfers 1.4 MB, producing an estimated 0.40g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.07g, network 0.07g, end-user device 0.25g.
Got: 0.40g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 47.5 kg CO2/year
With 10,000 page views per month, this page would generate approximately 47.5 kg of CO2 annually — equivalent to charging 5932 smartphones.

0.40g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 71% of websites

Sustainable Web Design model v4 · Page size: 1.4 MB

Your site
0.40g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.07g
Network
0.07g
End-user device
0.25g
At 10,000 monthly views: Monthly: 4.0 kg · Annual: 47.5 kg · ≈ 5932 smartphone charges
A+
Repeat Visit Weight
93% cached
PASS
93% cached
Info::
93% reduction on repeat visits
Returning visitors download only 100 KB (vs 1430 KB first visit). 35 of 36 resources are served from browser cache, saving 0.37g CO2 per repeat visit.
Info::
Repeat visit: 0.03g CO2 (first visit: 0.40g)
First visit
1430 KB
Repeat visit
100 KB

93% reduction on repeat visits

Saving 0.37g CO2 per returning visitor

35 resources served from cache · 1 resources re-downloaded

A
Carbon Budget
29th percentile
PASS
29th percentile
Info::
0.40g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 71% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 29th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.40g

29th percentile

Cleaner than 71% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 34% cleaner ✓
vs Target 21% cleaner ✓
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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