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https://barcelona.cat

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
55
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
2.23g CO2 per view
FIX
2.23g CO2 per view
Critical::
2.23g CO2 per page view
This page transfers 7.9 MB, producing an estimated 2.23g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.41g, network 0.39g, end-user device 1.43g.
Got: 2.23g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 267.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 267.8 kg of CO2 annually — equivalent to charging 33473 smartphones.

2.23g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 5% of websites

Sustainable Web Design model v4 · Page size: 7.9 MB

Your site
2.23g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.41g
Network
0.39g
End-user device
1.43g
At 10,000 monthly views: Monthly: 22.3 kg · Annual: 267.8 kg · ≈ 33473 smartphone charges
D
Green Hosting
Action
Unknown
FIX
Unknown
Info::
Hosting provider could not be identified
Without knowing the provider, we cannot determine their energy sourcing. Check with your hosting provider about their renewable energy commitments.
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 HostingUnable to Determine
Hosting Not identified✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

F
Carbon Budget
Action
95th percentile
FIX
95th percentile
Warning::
2.23g 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

2.23g

95th percentile

Cleaner than 5% of websites

✗ Above the median website

vs Median 272% more
vs Target 346% more
B
Transfer Efficiency
79% efficient
REVIEW
79% efficient
Info::
Transfer efficiency: 79%
An estimated 1729 KB (21%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1729 KB of unused JavaScript. This wasted data produces 0.48g of unnecessary CO2 per page view.
79% efficient

Total waste: 1729 KB (21% of page weight)

Unused JS 1729 KB

0.48g unnecessary CO2 per visit

Actual transfer 8069 KB
Theoretical minimum 6339 KB
Potential savings 1729 KB (0.48g 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
100% cached
PASS
100% cached
Info::
100% reduction on repeat visits
Returning visitors download only 31 KB (vs 8069 KB first visit). 271 of 277 resources are served from browser cache, saving 2.22g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 2.23g)
First visit
8069 KB
Repeat visit
31 KB

100% reduction on repeat visits

Saving 2.22g CO2 per returning visitor

271 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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