Why does a website cause CO₂ emissions in the first place? Quite simply, it requires energy for servers to provide it, networks to transmit it, and the end devices. Because electricity is still too often produced using fossil fuels, carbon emissions are caused. Not much energy is often required to call up a single, average website, so this often involves only a few grams of CO₂ (depending on the client - a PC desktop requires significantly more energy than an iPhone, for example). But there are about 2 billion websites with many individual web pages and billions of Internet users. So that adds up - to millions of tons of carbon dioxide.
An individual Internet user may be able to limit his or her use in the process and avoid certain applications altogether (such as TikTok because of its particularly poor energy and CO₂ footprint), but he or she has no influence on significant aspects of the overall energy demand and associated emissions. Of course, economical end devices and green electricity help, but that is just one part of the so-called "digital carbon footprint."
That's why this is part of the website operator's Scope 3 emissions - only he or she can ensure CO₂ neutrality, which should really be a given for everyone. Just as it is socially unacceptable to poop in the hotel pool, there should be social (and legal) consequences for those whose emissions make life on our planet worse; even more so when emissions are easy to avoid and offset.
Various tools can be used to measure the performance of a website when it is accessed. The best known is certainly Google PageSpeed Insights. If you reduce the loading time and other aspects of the presentation, you usually also reduce the energy consumption in general. Of course, servers and infrastructure are neglected in this analysis. If you want to know more precisely, you can use other tools to calculate the approximate emissions for individual page impressions for different locations, end devices and situations (e.g. recurring visitors, where less data needs to be transferred due to a local buffer) and extrapolate accordingly based on your own website statistics. In onEco +Analytics, these three aspects are linked together, technical performance, total emissions and website statistics are evaluated and merged in a GDPR-compliant manner.
Regardless of the specific results of a measurement, there are some tips that can help reduce data volume, processing time, energy requirements and emissions:
Renewables for server and infrastructure
Run your own servers and infrastructure on renewable energy or choose providers that do.
Content delivery networks can save energy
With a good content delivery network (CDN), load times and server load can be reduced. If you have to take care of this yourself, you will need some technical knowledge. In case of doubt, the GDPR can also be an issue, which must then be taken into account.
Modern file formats for images
Optimize images - with modern file formats like WebP (bitmap) and SVG (vector data) the amount of data to be transferred can be reduced considerably compared to older formats like GIF, PNG and JPEG. This often even improves the display quality, for example when typical logos are included as SVG rather than PNG.
Properly sized images
Responsive images not only adapt to different end devices in terms of display size, but also in terms of the size transferred - different (smaller) images are therefore transferred to smartphones than to desktop browsers.
Load only when needed (also known as lazy-load) - load data-intensive website content such as images or videos only when they are needed because they are in the visible part of a web page.
Avoid videos - especially if videos are only decorative, they should be avoided altogether. Sorry.
Switch off light – on the screen
Dark backgrounds - many modern screens use much less power when pixels are dark and not bright. Dark backgrounds are therefore a very simple means, which should be a matter of course at least in night mode.
Data compression - a web page can also be compressed automatically if the server and browser support it. This can be set at the server level. This reduces the loading time and the amount of data to be transferred.
Use server cache to reduce server load - this works for database queries and views.
Enable browser cache - by providing the right header information, the browser cache can be used optimally to reduce the amount of data and loading time for recurring visits.
HTTPS and HTTP/2 - both are not only better in their own right, but also help reduce energy consumption.
Even if you operate your own website on climate-neutral servers, the infrastructure and end devices regularly produce emissions from fossil fuels in power generation, which are then part of your own Scope 3 emissions. These can be reduced through appropriate measures - but not completely avoided. What remains should therefore be offset by emission certificates. There are many providers for this - depending on certification, projects and transparency, the price varies considerably. With onEco +Analytics, unavoidable emissions are automatically offset.
There is the saying "Do good and talk about it". That may be true. But here it is still more a simple question of transparency, which is possible even without disclosing one's own website statistics, for those who just don't want to. Because this transparency can be established by the certification of website efficiency and compensation of remaining emissions by a third party as well. This is exactly what onEco +Analytics offers through the connection to onEco +Disclosure. Via a badge from onEco on your own website, every user can then access the report on the certification of your website's climate friendliness.