Your Website Carbon Footprint: The Impact Of Slow Page Speed

Last updated on Feb 15th, 2024 | 4 min

TL;DR: Achieving faster page load times reduces carbon emissions by decreasing energy use across data centers, networks, and devices. Solutions include optimizing images, minimizing code, leveraging efficient hosting, and adopting green web practices.

When we talk about having a slow website, we usually mention how it will negatively affect your users’ experience and bottom line. 

But did you know that the cost of a sluggish website extends beyond just losing sales?

It actually pollutes the environment! 

Yes, you read that right. 

And in this article, we will discuss how that is even possible, what tools you can use to monitor and measure your site’s carbon emissions, and most importantly - how to reduce them. 

Read on! 

How Websites Contribute to Higher Carbon Emissions

Given its immaterial nature, it’s hard to comprehend how our websites or doing anything online can negatively impact the environment. 

When we talk about carbon emissions, footprint, and pollution, the last thing we’d mention is the Internet. We discuss burning fossil fuels, deforestation, and heavy industrial processes — all things we can see and have seen with our own eyes. 

Well, you might be surprised by the next sentence:

Every action we take online produces a carbon footprint.

How is that possible?

The answer - electricity.

The internet's energy consumption and emissions are massive. It powers data centers, telecommunication networks, and the devices we use to browse the web.

To understand how much electricity is used:

The internet consumes 416.2TWh per year. That's more than the entire United Kingdom.

But let’s zone in a little bit. How does a website contribute to this astonishing number? 

Well, every interaction with your website results in electricity being used. Just think about it:

  • For a visitor to load your page, they send an HTTP request to your server.
  • Then, the server needs to send back a response.
  • Finally, the browser has to process the received data.

Each of these processes uses electricity. And that’s just one user loading a single page. Now multiply this by 10, 100, 1000. You get the point. 

Also, let’s not forget the data centers where all your site’s information is stored. The amount of energy they need to operate 24/7 is HUGE. 

In fact, according to NowVertical:

“Data centers account for around 2% of all global carbon emissions. In the US alone, 0.5% of total greenhouse gas emissions are attributed to data centers.”

For reference, the aviation industry is responsible for around 2.5% of global CO2 emissions. That’s how impactful the Internet is. 

We should make something clear:

Not all websites are equal. Depending on their size, traffic, and level of optimization, the CO2 footprint can vary. 

But one thing is for sure:

The slow-loading websites are the worse. 

Here’s why…

Why Slow Websites Make Things Even Worse

One of the main reasons slow websites are problematic is because of their page weight. 

Page weight refers to the total size of a webpage, including all the files, images, scripts, and other content downloaded when a user visits a website. 

The larger the page weight, the more data needs to be transmitted. In turn, the site takes longer to load, and more electricity is used. 

Unfortunately, Page Weight is a metric that has continuously grown in the last ten years, and it doesn’t seem to stop any soon.

According to the HTTP Archive, a website's average page weight has steadily increased over the years. 

From 524.4 KB (desktop) and 202.5 KB (mobile) in 2011:

Page Weight 2011 stats

To 2361.1 KB (desktop) and 2076.9 KB (mobile) in 2023:

Page Weight 2023 stats

Another issue with slow websites is that because they take forever to load, users often refresh the page multiple times, trying to get it to load faster. 

Each refresh sends another request to the server, using more data and electricity. This not only wastes time and resources but also puts unnecessary strain on the website's servers and infrastructure.

So what we’re trying to say is: 

Reducing a site’s carbon footprint goes hand-in-hand with improving its performance.

But before doing that, you need to know how much CO2 emissions your website emits. 

How to Measure Your Website Carbon Footprint

Searching for “website carbon calculator” will bring up all kinds of results. 

But our go-to testing tool is Website Carbon Calculator from Wholegrain Digital, a London-based WordPress sustainable agency.

To calculate the energy and emission of a web page, they use the following data points:

  • Data transfer over the wire
  • Energy intensity of web data
  • Energy source used by the data center
  • Carbon intensity of electricity
  • Website traffic

But all of this is happening in the background. 

On the front, all you have to do is input your site’s URL, and in a couple of seconds, you get all the information presented with beautiful graphics:

Website Carbon Calculator results page

But these stats could be hard to understand when they are nothing to compare. Luckily, Wholegrain Digital thought about that, so when you scroll, you will see all kinds of real-life comparisons:

Website Carbon Calculator comparison section

Of course, there are other testing solutions you can try:

Regardless of your choice, the most crucial part comes after you test your website - how to reduce your site’s carbon footprint.

How to Reduce Your Website’s Carbon Footprint

It’s a two-fold strategy:

  1. Move to a sustainably-powered hosting provider
  2. Optimize your site’s performance

Move to a sustainably-powered hosting provider

You already know that the majority of the carbon emissions produced by the Internet originate from the extensive data centers that support websites worldwide. 

The need to consume a lot of energy to operate the servers and maintain their cool temperature, among other things. And this energy consumption is unavoidable. 

Nevertheless, selecting a hosting service that employs environmentally friendly energy sources to power its data centers is one way to diminish your website's carbon footprint. This approach ensures that the energy utilized by your site will have a less damaging effect on the environment.

The Green Web Foundation maintains a directory of 440+ green hosting companies in 37 countries all over the world. Some of the most popular include:

  • A2 Hosting
  • Kinsta
  • Cloudflare
  • Siteground
  • AWS
  • Dreamhost

And 434 more. So there’s plenty to choose from. 

Optimize your site’s performance

Switching to a green hosting provider is a massive step toward fewer CO2 emissions. 

But the most environmentally-friendly solution is to ensure your site uses less power in the first place.

You can achieve that by optimizing your resources so that the next time a user visits your site, your servers and their mobile device use less electricity. And here are some web performance techniques that can help:

  • Image optimization - When images are not optimized, they can be too large, which means they take longer to load and require more data to be transferred. This can cause delays and increase the energy required to transmit the data. However, by applying different optimizations such as compression, WebP conversion, and lazy loading, your images will load faster, reducing the amount of data that needs to be transferred and the energy required.
  • Enable caching - Every time a user visits your site, they have to download a lot of files like images and code. Caching stores these files closer to them, so they don't have to be downloaded again when they revisit your website. This means fewer data has to be sent between the servers and their device, which saves energy and reduces carbon emissions.
  • Code minification -  Your site’s code probably contains unnecessary characters, spaces, and comments that increase the file size, which means it requires more energy to be transmitted. Applying minification will remove all unnecessary characters and spaces from the code while keeping the code's functionality intact. As a result, your code files will be leaner, smaller, and less energy-demanding.
  • Lazy loading - With lazy loading, only the content immediately visible on the user's screen is loaded initially, and the rest is loaded as they scroll down the page. This means they don’t have to download all the content at once, which reduces the amount of data that needs to be transferred and the energy required to transmit it.
  • Use a CDN - A Content Delivery Network can reduce your CO2 footprint by reducing the distance that data has to travel between servers and users' devices, which in turn reduces the amount of energy required.

Speed Up Your Website and Lower CO2 Emissions with NitroPack

It’s up to you to find the most environmental-friendly hosting provider that best suits your needs. 

For everything performance-related, you can use NitroPack

NitroPack is a web performance solution that provides your with 35+ speed optimization features:

  • Advanced caching
  • Image compressions, lazy loading, and WebP conversion
  • Built-in CDN
  • Code minification and compression
  • JavaScript lazy loading 
  • Font optimization
  • And more…

But the best part is that all optimizations are applied automatically. All you have to do is install it, and shortly your site’s carbon emission will drop like a stone.

Don’t believe us?

Here’s our website with and without NitroPack enabled:

NitroPack CO2 emissions without NitroPack enabled

Without NitroPack 

NitroPack CO2 emissions with NitroPack enabled

With NitroPack

And these are the results of one of our clients:

NewBeauty CO2 emissions without NitroPack

Without NitroPack

NewBeauty CO2 emissions with NitroPack

With NitroPack

Put simply:

With NitroPack, businesses reduce their impact on the environment massively. 

Lower your site’s CO2 emissions automatically. Install NitroPack today →

Niko Kaleev
Web Performance Geek

Niko has 5+ years of experience turning those “it’s too technical for me” topics into “I can’t believe I get it” content pieces. He specializes in dissecting nuanced topics like Core Web Vitals, web performance metrics, and site speed optimization techniques. When he’s taking a breather from researching his next content piece, you’ll find him deep into the latest performance news.