The most surprising sources of greenhouse gases

A server farm - one of the biggest sources of greenhouse gases
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Most people know that flying and leaving the lights on releases a lot of carbon dioxide. However, at FootprintFacts, we were curious if there were any surprising sources of greenhouse gases. We did some research and made some very surprising discoveries.

Few people know that things such as using the internet, buying glass bottles and composting food waste lead to so much carbon dioxide. In this article, we explain in detail why this is the case.

The greenhouse gases released by the internet

The internet has a bigger carbon footprint than air travel. This is shocking, since everyone is aware of the shocking impact of air travel but few people understand how bad the internet is. Aside from the manufacturing and powering of products, which can lead to huge CO2 emissions alone insert article here, one of the more surprising sources of carbon dioxide comes from the data we use. The internet itself releases around 830 million tonnes of carbon dioxide annually. That’s 2% of the global carbon footprint, or 110kg per person per year.

How does the internet actually release carbon dioxide?

The main carbon footprint of the internet come from the server farms. These are necessary since they store all the data which we use on the internet. These server farms use huge amount of energy to power and cool the equipment used to store the data. In fact, in the USA around 2% of energy usage comes from server farms.

What can I do to help this?

The internet is one of the best solutions for tackling climate change. This is because it is a great alternative to travelling for meetings or getting information in a physical location. However, there are still some ways in which we can cut unnecessary internet usage. 

  1. Cut unnecessary emails – if every person in the UK sent one less “thank you” email a day, it could save 16,433 tonnes of CO2. This is the equivalent to the carbon footprint of 2000 people.
  2. Unsubscribe from mailing lists – if you are receiving emails you don’t want, simply click unsubscribe at the bottom. This will reduce the number of emails you get sent yearly.
  3. Reduce time on the phone ­– a video call can release from 4kg-215kg of carbon dioxide into the atmosphere in a matter of hours.

However, it is also important to remember that the impact of using the internet is almost always less than travelling to meet someone. The most important thing to reduce is unnecessary internet usage.

Glass Bottles and glass manufacturing

How much CO2 does glass manufacturing release?

The production of glass can release surprisingly large volumes of CO2. Glass furnaces are always running. This uses a huge amount of energy since they operate at 1500oC and so release a lot of carbon dioxide. In the UK there are around 10 glass manufacturers, however a lot of the glass used is imported. This industry releases an estimated 2 million tonnes of carbon dioxide per year in the UK alone. 

However, using glass is not always bad. This is because glass is recyclable, whereas plastics are less recyclable. Usually, glass is recycled into another glass product, so it is not wasted and does not have to be remanufactured. However, plastics are usually transformed into plastics-based clothes. This process is “downcycling”.

The most important thing when using glass is not to waste. If you recycle, the carbon footprint of that glass will massively reduce over its lifetime. Glass is better for the environment than plastic but only if used right.

Composting is a source of greenhouse gases!

Composting is one of the most surprising sources of greenhouse gases. This is because most people expect it to be a very environmentally friendly thing to do. Recycling does not actually release carbon dioxide, but it released nitrous oxide and methane – two of the more potent greenhouse gases. You can read about the comparison of the greenhouse gases here

Methane and nitrous oxides are formed as a result of anaerobic respiration. All living being carry out respiration, which releases the energy from glucose (sugar). It is necessary to live! However, if there is insufficient oxygen (like in the middle of a compost heap), the macrobacteria that break down the compost will undergo anaerobic respiration. This releases these greenhouse gases.

This article estimates that the carbon footprint equivalent per tonne of compost is 233.4kg. However, according to this article, compost and manure can have a more environmentally friendly use. This is through energy generation.

Methane releases carbon dioxide and energy when it burns in air. This energy is ‘carbon neutral’ since it takes one carbon dioxide equivalent and converts it to carbon dioxide. Carbon dioxide is actually less dangerous for the environment than methane. Whilst producing manure for the purpose of energy generation is very inefficient – if manure and compost are a necessity, this is a good use for them.

Shipping and goods transport can be a surprising source of greenhouse gases

Maritime transport releases 940 million tonnes of carbon dioxide per year. This is more than the entire aviation industry. Most of this shipping is for the purpose of transporting goods. This arises as a side effect of globalisation.

Globalisation means that it is often cheaper for a European company to produce their products in China and ship them to Europe. Whilst this is financially beneficial, it means that a lot of carbon dioxide is released as a result of the need to transport goods halfway round the world. There are several ways that we, as consumers are able to reduce this.

  1. Research – find out or contact businesses to ask where they manufacture their products. If they manufacture closer to where you live, the carbon footprint will be lower.
  2. Check product labels – often they show where the product was produced (especially in food). Try to buy food that is produced closer to where you live.

Finally, we can advocate for more localised production. Globalisation has been dominant for several years, but it is clear that in manufacturing it is not sustainable. Whilst shipping releases almost a billion tonnes of carbon dioxide per year, we must find alternative ways to source products. However, there is hope for the future. It is likely that ships powered by more eco-friendly fuels are not too far away. You can read about the latest developments in eco shipping here.


With so many surprising sources of greenhouse gases, it is seemingly an impossible task to know the carbon impact of every action we have. However, it is very possible to be conscious of the most impactful actions so that we are able to reduce our own footprint and educate others. Checking out the latest news and climate discoveries as well as researching how to reduce our carbon footprint can have a huge impact. You can do this by taking our carbon footprint calculator, or reading our comprehensive article: “How to reduce your carbon footprint”.

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