https://bbc.co.uk
Sustainability
· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
78
GRADE
C
FIX
2
REVIEW
2
PASS
3
INFO
1
Checks
83 PASS 2 REVIEW 2 FIX
DCO2 Per Page LoadAction0.85g CO2 per viewFIX
CO2 Per Page Load
Action0.85g CO2 per view
0.85g CO2 per view
Info::
0.85g CO2 per page view
This page transfers 3.6 MB, producing an estimated 0.85g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.18g, end-user device 0.66g.
Got: 0.85g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 102.5 kg CO2/year
With 10,000 page views per month, this page would generate approximately 102.5 kg of CO2 annually — equivalent to charging 12809 smartphones.
Info::
Green hosting reduces data center emissions
0.85g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 43% of websites
Sustainable Web Design model v4 · Page size: 3.6 MB
Your site
0.85g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.02g
Network
0.18g
End-user device
0.66g
At 10,000 monthly views: Monthly: 8.5 kg · Annual: 102.5 kg · ≈ 12809 smartphone charges
DCarbon BudgetAction57th percentileFIX
Carbon Budget
Action57th percentile
57th percentile
Warning::
0.85g CO2 — above the median website (0.60g)
Heavier than an estimated 43% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 57th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.85g
57th percentile
Cleaner than 43% of websites
✗ Above the median website
vs Median 42% more
vs Target 71% more
BTransfer Efficiency87% efficientREVIEW
Transfer Efficiency
87% efficient
87% efficient
Info::
Transfer efficiency: 87%
An estimated 464 KB (13%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 464 KB of unused JavaScript. This wasted data produces 0.11g of unnecessary CO2 per page view.
Total waste: 464 KB (13% of page weight)
Unused JS 464 KB
0.11g unnecessary CO2 per visit
Actual transfer 3694 KB
Theoretical minimum 3230 KB
Potential savings 464 KB (0.11g CO2)
See Deep Analysis sections above for specific optimizations.
BWeb Font Weight VariantsNo detectable Google Fonts weightsREVIEW
Web Font Weight Variants
No detectable Google Fonts weights
No detectable Google Fonts weights
Info::
No detectable Google Fonts weights
The analyzer detects font weights via Google Fonts URL parameters (~70% of font-using sites). Self-hosted fonts and non-Google CDN fonts aren't visible to URL-based detection. If you self-host fonts, manually audit how many @font-face weights you ship -- 2-3 weights per family is typically enough; 5+ is usually unused payload.
A+Green HostingGreen (both)PASS
Green Hosting
Green (both)
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Next.js, CDN: Fastly
Info::
Next.js: Verified by the Green Web Foundation
Info::
Fastly: 100% renewable energy for edge network
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 Hosting✓ Green Hosted
Hosting Next.js✓CDN Fastly✓
Next.js: Verified by the Green Web Foundation
Fastly: 100% renewable energy for edge network
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight95% cachedPASS
Repeat Visit Weight
95% cached
95% cached
Info::
95% reduction on repeat visits
Returning visitors download only 184 KB (vs 3694 KB first visit). 223 of 227 resources are served from browser cache, saving 0.81g CO2 per repeat visit.
Info::
Repeat visit: 0.04g CO2 (first visit: 0.85g)
First visit
3694 KB
Repeat visit
184 KB
95% reduction on repeat visits
Saving 0.81g CO2 per returning visitor
223 resources served from cache · 4 resources re-downloaded
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
Whether the site is served from green-energy infrastructure
Green Hosting
This site is hosted on green energy infrastructure
Provider: Fastly
Image Optimization137 images, 80 KB total, 0 KB wastedINFO
Image Optimization
137 images, 80 KB total, 0 KB wasted
Image Optimization Audit
Total Images
137
Total Size
80 KB
67 missing alt text 137 missing dimensions 67 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.