I’ve been reading a lot recently about how our rapidly growing reliance on web apps is using more resources and impacting on climate change. At the same time, the usual questions that I always have around “how much is down to me?” and “what can I do about it?” seem to go unanswered. Heck, it’s hard to find out whether this is something we should even be worried about. This strikes me as ironic given the truly stunning capacity and speed of our data storage and retrieval technology that is driving the information age.

“Measure what it measurable and make measurable what is unmeasurable”

Wise words from Galileo, but applying measurement to our ever growing Internet habit proves rather tricky.  I set out to try and fix this. The answers below can only be a crude estimate and better numbers will give a better answer. I’ve had to patch information together from a range of sources. This is a starter though, and I found the result quite startling.

What we know

The global data centres that power the Internet  apparently used 417 terawatt hours of electricity in 2015. That is a lot of leccy – around 1.7% of total global electricity production of 25,500 terawatt hours, and considerably more than the total electricity output of the UK.

We also know that global Internet traffic was around 1 zettabyte of data in the same year. That is an equally jaw dropping number – a zettabyte is a trillion gigabytes, or 152 million years of high definition film watching.

On this basis, the electricity used in these data centres can be multiplied  by the world average carbon intensity average for electricity production of 500grams of CO2e (greenhouse gases) for every kilowatt hour of electricity produced.  This gives a total estimated emissions figure of 208.5 billion tonnes of greenhouse gas coming from the electricity used to power the world’s data centres.

If we then assume that all that 1 zettabyte of internet data used in 2016 was handled by one of these data centres, this means that 1 gigabyte of Broadband Internet data produces around 0.2kg CO2e of greenhouse gas per gigabyte. We also probably need to add in an amount for the ’embedded carbon’ in making the estimated 80 million servers and supporting power cables/cooling equipment etc, for which I used the estimates in this report. We could also add something for staff costs and the embedded carbon of the building itself, but it looks like these will be very small or even negligible in carbon terms, compared to the footprint of the electricity and hardware.

The Take Away

So the total of downloading 1 gigabyte of internet data works out at 0.213 kg CO2e on these numbers. Now we can put all this in terms of different bands of user, to give an idea of how much that works out for different users:

User type Description Gigabytes

per Year

Carbon footprint of Internet use (kg CO2e)
Very high super fast BroadBand use All the below plus lots of gaming 9,600 2050
High super fast Broadband use Lots of HD films, catch up TV, streaming with Netflix, Spotify, Iplayer, Youtube etc and maybe a bit of online gaming 4,800 1025
Average super fast Broadband use SD films, catch up TV, streaming with Netflix, Spotify, Iplayer, Youtube, etc 2,400 513
Light Internet use Web Browsing, emails, small amount of streaming/catch up 960 205
Very light/ non-Broadband internet use web browsing and emails 240 51

I would say that if you don’t have Broadband at home, then the total amount of data will be too low to worry about – even if you are on the internet all day. I think it would be hard to get to the higher levels of data usage without using video streaming services. The average carbon footprint across all 3.5billion users of the Internet is a meagre 61 kg CO2e per year – and this will include a substantial amount of data used exclusively by business etc. It is certainly hard to think that a user in India or China who checks emails or surfs the Internet a couple of times a week on a slow connection in an Internet cafe will be getting to anywhere near those levels of consumption.


On the evidence of this, it looks like our household’s fairly heavy Internet usage of 2,735 gigabytes annually is adding 0.6 tonnes (600 kg) of greenhouse gas to our household footprint every year. When held up against other things such as our car, heating, flights, or food, this is still actually fairly significant; if these figures are correct, then our data use could produce as much greenhouse gas as our electricity consumption at home if it continues to increase over the next few years. This requires further investigation, I feel. At a global level, our appetite for online entertainment is growing at such a mind-boggling rate, that the big numbers driving this analysis will quickly be dwarfed by our ever increasing data consumption. If all the electricity that powers the data centres came from clean renewable sources, the carbon footprint of the Internet would be extremely small. Some of the big companies are making efforts in this direction, but we aren’t anywhere near to there yet, unfortunately.

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