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https://cochranelibrary.com

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
87
GRADE
B
FIX
0
REVIEW
2
PASS
4
INFO
0
Device:
Mobile Desktop
Checks
6
4 PASS 2 REVIEW
B
Carbon Budget
34th percentile
REVIEW
34th percentile
Info::
0.44g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 66% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 34th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.44g

34th percentile

Cleaner than 66% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 27% cleaner ✓
vs Target 12% cleaner ✓
B
Transfer Efficiency
81% efficient
REVIEW
81% efficient
Info::
Transfer efficiency: 81%
An estimated 360 KB (19%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 360 KB of unused JavaScript. This wasted data produces 0.08g of unnecessary CO2 per page view.
81% efficient

Total waste: 360 KB (19% of page weight)

Unused JS 360 KB

0.08g unnecessary CO2 per visit

Actual transfer 1904 KB
Theoretical minimum 1543 KB
Potential savings 360 KB (0.08g CO2)

See Deep Analysis sections above for specific optimizations.

A
CO2 Per Page Load
0.44g CO2 per view
PASS
0.44g CO2 per view
Info::
0.44g CO2 per page view
This page transfers 1.9 MB, producing an estimated 0.44g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.09g, end-user device 0.34g.
Got: 0.44g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 52.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 52.8 kg of CO2 annually — equivalent to charging 6602 smartphones.
Info::
Green hosting reduces data center emissions

0.44g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 66% of websites

Sustainable Web Design model v4 · Page size: 1.9 MB

Your site
0.44g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.09g
End-user device
0.34g
At 10,000 monthly views: Monthly: 4.4 kg · Annual: 52.8 kg · ≈ 6602 smartphone charges
A+
Green Hosting
Green (both)
PASS
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Cloudflare, CDN: Cloudflare
Info::
Cloudflare: Verified by the Green Web Foundation
Info::
Cloudflare: 100% renewable energy for global network since 2019
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 Cloudflare✓CDN Cloudflare✓

Cloudflare: Verified by the Green Web Foundation

Cloudflare: 100% renewable energy for global network since 2019

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 21 KB (vs 1904 KB first visit). 116 of 119 resources are served from browser cache, saving 0.44g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.44g)
First visit
1904 KB
Repeat visit
21 KB

99% reduction on repeat visits

Saving 0.44g CO2 per returning visitor

116 resources served from cache · 3 resources re-downloaded

A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

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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