https://www.nature.com
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
90
GRADE
A
FIX
0
REVIEW
2
PASS
4
INFO
0
Checks
64 PASS 2 REVIEW
BTransfer Efficiency85% efficientREVIEW
Transfer Efficiency
85% efficient
85% efficient
Info::
Transfer efficiency: 85%
An estimated 214 KB (15%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 214 KB of unused JavaScript. This wasted data produces 0.05g of unnecessary CO2 per page view.
Total waste: 214 KB (15% of page weight)
Unused JS 214 KB
0.05g unnecessary CO2 per visit
Actual transfer 1435 KB
Theoretical minimum 1220 KB
Potential savings 214 KB (0.05g CO2)
See Deep Analysis sections above for specific optimizations.
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
ActionWhether the site is served from green-energy infrastructure
Green Hosting
No green hosting detected
ACO2 Per Page Load0.33g CO2 per viewPASS
CO2 Per Page Load
0.33g CO2 per view
0.33g CO2 per view
Info::
0.33g CO2 per page view
This page transfers 1.4 MB, producing an estimated 0.33g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.07g, end-user device 0.25g.
Got: 0.33g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 39.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 39.8 kg of CO2 annually — equivalent to charging 4975 smartphones.
Info::
Green hosting reduces data center emissions
0.33g
Carbon Footprint per page view
✓ Below sustainability target (0.50g)
Cleaner than 77% of websites
Sustainable Web Design model v4 · Page size: 1.4 MB
Your site
0.33g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.07g
End-user device
0.25g
At 10,000 monthly views: Monthly: 3.3 kg · Annual: 39.8 kg · ≈ 4975 smartphone charges
A+Green HostingGreen (both)PASS
Green Hosting
Green (both)
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Google Cloud, CDN: Fastly
Info::
Google Cloud: Carbon-neutral since 2007, 100% renewable energy matched since 2017
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 Google Cloud✓CDN Fastly✓
Google Cloud: Carbon-neutral since 2007, 100% renewable energy matched since 2017
Fastly: 100% renewable energy for edge network
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight96% cachedPASS
Repeat Visit Weight
96% cached
96% cached
Info::
96% reduction on repeat visits
Returning visitors download only 50 KB (vs 1435 KB first visit). 54 of 55 resources are served from browser cache, saving 0.32g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.33g)
First visit
1435 KB
Repeat visit
50 KB
96% reduction on repeat visits
Saving 0.32g CO2 per returning visitor
54 resources served from cache · 1 resources re-downloaded
ACarbon Budget23th percentilePASS
Carbon Budget
23th percentile
23th percentile
Info::
0.33g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 77% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 23th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.33g
23rd percentile
Cleaner than 77% of websites
✓ Below the Web Sustainability Guidelines target
vs Median 45% cleaner ✓
vs Target 34% cleaner ✓
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.