If it takes you three minutes to write an email on a smartphone then the total CO2 involved in that exercise could amount to about 1 gram. Writing the same email on a laptop could amount to 5 grams of CO2, while on a desktop it could be as much as 11 grams.

The above figures take account of the CO2 produced in manufacturing a particular device and the CO2 created during use. For many digital products, up to 80% of the CO2 is generated during manufacture. So, for example, manufacturing a typical smartphone results in about 60 kg of CO2, while using that smartphone for a year creates 4–6 kg of CO2.

Thus, if you want to reduce your digital CO2 impact you should choose the smallest and least energy-intensive device possible and hold on to it as long as possible. Because when most of the CO2 occurs during manufacture, the life of the device becomes critical if we want to reduce its CO2 impact.

Unfortunately, in the digital world we have a perfect storm of pollution, a truly vicious circle of planned obsolescence. The average smartphone is replaced after a couple of years. It’s estimated that we would need to keep our laptops for twenty years if we were to properly account for the emissions they cause during manufacture, but we only hold on to them for about five. Added to this disturbing picture is the fact that fewer than 20% of digital products are recycled. Digital is a dirty industry, however shiny it looks on the surface.

Digital trains us to treat energy as a limitless, free resource. We are constantly encouraged to consume more of it, whether through techniques that autoplay the next video, or the psychological tricks that encourage us to be relentlessly engaged and scrolling on social media. In the tech industry, the more energy we consume the more money they make. The tech business model involves the maximum exploitation of cheap energy. These cheap and “free” models feed the fires of the climate emergency.

We can slowly withdraw from our digital addictions, and one of the ways is to set limits to the amount of energy we consume using digital devices, both our own personal energy and the electrical energy required.

We can choose to try and use the least energy possible when using digital. One way of doing that is to choose the device with the smallest CO2 impact. However, when I did a recent survey and asked people if they tried to use digital devices that consume the least energy possible (smartphones instead of laptops, laptops instead of desktops, small screens instead of large screens), 65% said no.

Digital is physical. The Cloud is on the ground. The digital industry is producing over 50 million tons of e-waste every year. That’s the equivalent of dumping 1,000 laptops every second. The problem is getting worse. The total quantity of e-waste is doubling roughly every 15 years. We can solve this problem. But we need a radical rethink of how we see technology. Buy to last. Use sparingly.