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https://sierraclub.org

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
64
GRADE
D
FIX
3
REVIEW
2
PASS
1
INFO
0
Device:
Mobile Desktop
Checks
6
1 PASS 2 REVIEW 3 FIX
D
CO2 Per Page Load
Action
0.99g CO2 per view
FIX
0.99g CO2 per view
Info::
0.99g CO2 per page view
This page transfers 3.5 MB, producing an estimated 0.99g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.18g, network 0.17g, end-user device 0.64g.
Got: 0.99g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 119.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 119.3 kg of CO2 annually — equivalent to charging 14907 smartphones.

0.99g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 39% of websites

Sustainable Web Design model v4 · Page size: 3.5 MB

Your site
0.99g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.18g
Network
0.17g
End-user device
0.64g
At 10,000 monthly views: Monthly: 9.9 kg · Annual: 119.3 kg · ≈ 14907 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 Platform.sh✗CDN Incapsula✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

D
Carbon Budget
Action
61th percentile
FIX
61th percentile
Warning::
0.99g CO2 — above the median website (0.60g)
Heavier than an estimated 39% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 61th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.99g

61st percentile

Cleaner than 39% of websites

✗ Above the median website

vs Median 66% more
vs Target 99% more
B
Transfer Efficiency
86% efficient
REVIEW
86% efficient
Info::
Transfer efficiency: 86%
An estimated 485 KB (14%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 485 KB of unused JavaScript. This wasted data produces 0.13g of unnecessary CO2 per page view.
86% efficient

Total waste: 485 KB (14% of page weight)

Unused JS 485 KB

0.13g unnecessary CO2 per visit

Actual transfer 3593 KB
Theoretical minimum 3107 KB
Potential savings 485 KB (0.13g 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
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 37 KB (vs 3593 KB first visit). 143 of 149 resources are served from browser cache, saving 0.98g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.99g)
First visit
3593 KB
Repeat visit
37 KB

99% reduction on repeat visits

Saving 0.98g CO2 per returning visitor

143 resources served from cache · 6 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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