Technology is now ubiquitous in our lives. From morning to night we depend on it for work, rest, social relations, leisure, travel and everything else we can imagine. The drive to digitise society was initially underpinned by its green credentials: digital communications reduce travel and save paper. But while hardly anyone can ignore the climate and environmental impact of transport, deforestation or other activities anymore, there does not seem to be the same insistence on explaining that digital technologies also have a serious carbon footprint, and not just in the manufacture of the devices or their disposal, but also in their very use. The meteoric growth of this sector will only increase its climatic impact in the coming decades unless not only manufacturers and suppliers, but also users themselves, adopt more sustainable practices in our digital lives.
While we may be comfortable relying on companies and government regulations to take action on climate change, we must not forget that the ultimate recipients of many supply chains are individual citizens. The greenhouse gases (GHGs) we emit directly from our homes account for around 20% of the global total—which is already a very considerable figure—but if we add to this the indirect emissions from all the products and services we consume, the figure rises to more than 60%, or up to 80% in a high-income country such as the US. Therefore, our consumption habits also have a role to play in maintaining the status quo or transforming it towards sustainable models.
In the share of GHG emissions due to households, the usual culprits stand out: energy and transport account for 55% of the total, followed by food, which contributes almost 17%. In this distribution, other categories are more concealed in the figures; for example, the textile industry, which accounts for a large part of our consumption, is responsible for between 4% and 10% of global GHGs. Similarly, in this pie of household emissions drawn up by researchers at the University of Michigan, the contribution of the technology sector is diluted: where do we find the impact of technology? Is it in the 0.1% labelled “electronics” (which rises to 6.3% if emissions exported to other countries are taken into account)? In a part of the almost 20% corresponding to services? In another part of household energy?
Digitalisation’s false green label
First of all, and given that in the now almost distant past the digitisation of communications came with a green label—the famous “print only if necessary” at the bottom of so many emails—it is worth asking to what extent this substitution is environmentally advantageous. Of course, we know that paper is made from wood, and that wood is harvested from trees. Some estimates have calculated that digitisation could avoid 25% of paper consumption, which would result in greater conservation of forests and thus maintain the carbon they sequester.
But for their part, the paper and printing industries are quick to dismiss these anti-paper claims as greenwashing, arguing that most of the logging does not go into papermaking, that the majority of wood fibre used comes from recycling and sawmill residue, and that this sector only emits 0.8% of European GHGs. In fact, in almost all cases companies acknowledge that the transition to a paperless model has not been driven by environmental concerns at all, but by cost savings and greater business efficiency, something that 83% of respondents in the US also recognised. Be that as it may, the truth is that the paper industry’s arguments have already convinced hundreds of companies around the world to remove anti-print messages from their communications. At the very least, according to the environmental consultancy Except, the comparison between paper and digital “is complex and context-dependent”.
Of course, an essential argument in this comparison is that digitisation is by no means free of having a large carbon footprint either. A 2011 study put the CO2 emissions of digital technologies at 2% of global emissions, estimating that their carbon footprint would less than double between 2007 and 2020, but that mobile communication-specific emissions would triple in the same period, reaching the equivalent of a third of the UK’s total emissions. In 2018, another study by Canada’s McMaster University put the share of global emissions from digital technologies at between 3% and 3.6% by 2020, up from 1.5% in 2007. A 2019 study by the French energy transition think-tank The Shift Project puts the figure at 3.7%, although other estimates put it at between 1.8% and 3.2%. By way of comparison, direct emissions from livestock account for 5%, and those from aviation add up to around 2.4%. In other words, emissions from digital technologies already exceed those from aviation, and are approaching those from livestock.
Smartphones and carbon footprint
The McMaster University study broke the data down into the factors responsible: data centres take the biggest burden, with 45% of the total, followed by networks with 24%. The rest is due to devices, with smartphones outweighing desktops, laptops, monitors and tablets. “The big surprise however in our findings is the disproportionate impact of smart phones by 2020, and its vertiginous growth from 4% in 2010 to 11% in 2020 in relative terms,” the authors wrote.
For mobile phones, their manufacturing phase accounts for between 85% and 95% of their entire carbon footprint—the production of one phone emits as much as 10 years of use—to which must be added other environmental impacts. The mining of materials, including so-called rare earths (metals with peculiar magnetic properties used in electronic devices), causes deforestation and produces toxic waste that destroys ecosystems. This is compounded by the pollution associated with the disposal of the devices, with little and inefficient recycling, generating large quantities of electronic waste.
For all these reasons, the first measure available to consumers for a more responsible use of technology is obvious: to exhaust the useful life of mobile phones and other devices. Smartphones are currently used for an average of 2-3 years, and in many cases they are replaced when they are still working due to the launch of new models. According to the McMaster researchers, “clearly this business model, while highly profitable to the smartphone manufacturers and the telecom industry, is unsustainable and quite detrimental to global efforts in GHG reductions”. A study by the European Environmental Bureau calculated that extending the use of electronic devices by one year would save the EU as much carbon emissions as taking two million cars off the road.
Energy-draining vampire devices
But this does not mean that consumers are powerless to reduce the climate impact of the technology we use. More than two thirds of emissions in this sector are reported to come from data centres and networks, i.e. usage. Carbon footprint researcher Mike Berners-Lee of Lancaster University estimated that using a mobile phone for one hour a day generates 1.25 tonnes of CO2 in a year. Every WhatsApp message, every interaction on social networks, every internet consultation, every song or streaming video has a carbon footprint. Many experts therefore call for a measured and moderate use of devices, limiting it to what is really necessary (see box below).
Finally, there is another aspect that penalises the environmental and climate cost of electronic devices, which is that many of them are never switched off. “Turn off your device when you don’t use it,” advises the consultancy Except. But how many smartphones, routers, home automation systems, personal assistants, laptops and other electronic devices stay on 24 hours a day, 365 days a year? Even those that are left idle, such as televisions or laptops, continue to consume energy. In the US, the Lawrence Berkeley National Laboratory has extensively studied this energy consumption, concluding that in the average home there are about 40 devices of all kinds on standby at any one time, which together consume almost 10% of residential electricity use; another study by the Natural Resources Defense Council in California increased this share to 23%.
In short, in the words of Tim Unwin, UNESCO Chair in ICT4D (Information and Communication Technologies for Development) at Royal Holloway, University of London, “the digital technology sector is very largely based on business models that have been designed specifically to be unsustainable.” But on the other hand, as noted in an editorial signed by more than thirty experts in the International Journal of Information Management, “technology is an integral component of the global efforts to get to net zero.” The World Economic Forum argues that digital technologies could reduce global emissions by 15%, a third of the reduction needed by 2030. Which way the balance of digital technologies tips in the climate emergency may largely depend on us, the users.
Is digital consumerism sustainable?
he rise of new technologies and the intensive use of smartphones have given rise to a new kind of consumerism: digital. At our fingertips are millions of songs, films and series, billions of emails, WhatsApp messages and social media posts. All of this may seem innocent, but the truth is that it is responsible for a large part of the carbon footprint of digital technologies. According to The Shift Project, “the current trend of digital over-consumption in the world is not sustainable”.
Although estimates vary, here are some published figures. The Shift Project puts internet traffic from online video viewing at 60%, which generates 300 million tonnes of CO2 annually, 1% of global emissions. A 2021 study estimated that watching streaming videos in HD or 4K (calculated specifically for Netflix) generates almost half a kilo of CO2 equivalent (CO2e) per hour; if 70 million users reduced the quality of videos to standard, 3.5 million tonnes of CO2e (t CO2e) would be saved each month, similar to eliminating 1.7 million tonnes of coal (however, other estimates of the footprint of online videos are considerably lower). One hour of video conferencing emits between 150 grams and 1 kilo of CO2. University of East London engineer Rabih Bashroush estimated that the five billion views of the 2017 Latino hit Despacito emitted around 250,000 tonnes of CO2.
In terms of communications, a study by OVO Energy calculated that if every email user in the UK avoided just one ‘thank you’ email every day—the most frequent message in more than 64 million unnecessary emails sent in the UK every day—it would save more than 16,000 tonnes of carbon per year, the equivalent of more than 81,000 flights from London to Madrid. According to an article at Reset.org, every search query emits 1.45 grams of CO2. Multiplied by billions of users, this results in a carbon footprint that, in the case of Google and according to data from the company itself (2016), amounts to 2.9 million t CO2e. SMS is the most sustainable messaging option (0.014 grams of CO2 per message), while a tweet produces 0.2 g, and a WhatsApp message only slightly less than an email. One minute of a phone call emits only slightly more than an SMS.
So here are some recommendations from the experts (in addition to the first and most fundamental one of prolonging the life of devices and recycling them): avoid unnecessary messages. Use social networks in moderation. Talk on the phone or send SMS rather than emails, and use emails responsibly, unsubscribing from mailing lists that do not interest you, avoiding “reply all” and limiting attachments; even an emoji adds up. Use documents in the cloud. Don’t leave the TV on if you are not watching it. Don’t play videos if you are only interested in the audio, which also applies to phone calls and video conferences. As far as possible, reduce the quality of videos and the brightness of screens, or use dark backgrounds.
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