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# System prepended metadata

title: Website Carbon proxy metrics

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# Website Carbon proxy metrics

Current website CO2 calculations (such as co2.js) are *very* broad brush, and won't always change even if you make improvements. However, there are easily collectable metrics that relate well.

> Rarely, can we directly measure our application's carbon cost, but if we follow a resource chain down and it eventually has a link to carbon emissions, then that is a good proxy for carbon.

Cedd Burge

www.linkedin.com/in/cedd-burge-90507027/

github.com/ceddlyburge

[@cuddlyburger](https://twitter.com/cuddlyburger)

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| Principle              | Client    | Server                       |
| ---------------------- | --------- | ---------------------------- |
| Carbon (efficiency)    | CPU usage | CPU usage                    |
| Electricity            | CPU usage | CPU usage                    |
| Carbon intensity       | -         | Power Usage Efficiency (PUE) |
| Embodied carbon        | CPU usage | CPU usage                    |
| Energy Proportionality | -         | *Server utilisation?*        |

| Measurement        | Client                   | Server             |
| ------------------ | ------------------------ | ------------------ |
| Carbon (emissions) | -                        | Vendor calculators |
| Energy             | CPU Usage                | CPU usage          |
| Cost               | -                        | Cost               |
| Networking         | Transfer size / distance |                    |
| Performance        | CPU usage                | CPU usage          |

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|             | Total Transfer Size<br />(121 pages) | Total CPU Client (benchmarked) |
| :---------- | :----------------------------------: | :----------------------------: |
| First Load  |               7.27 Mb                |              203               |
| Second Load |               0.28 Mb                |              185               |
| Mobile      |               7.43 Mb                |              163               |

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| Reccommendations                           |                              |
| ------------------------------------------ | ---------------------------- |
| Limit robots                               |                              |
| Delete content which isn’t human reachable | This still gets read by bots |
| Sign the [Sustainable Web Manifesto](https://www.sustainablewebmanifesto.com/)         | Obviously :)                 |
| Optimise images                            |                              |
| Set cache-control headers                  |                              |
| Reduce page size and javascript            |                              |
| Reduce mobile page size                    |                              |
| Simplify css                               |                              |



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