How your online life is polluting the planet

Choosing digital meetings, shopping and even exercise classes over their in-person alternatives can substantially reduce greenhouse gas emissions by avoiding transport-related pollution, but the environmental impact of our digital lives is also surprisingly high.

We don't often think about the various infrastructures required to do simple things like send an email or hold our photos—these digital things are stored in data centers that are often out of sight, out of mind.

However, digital activity has a surprisingly high environmental impact too, according to experts.

Along with the greenhouse gas emissions from substantial energy use by our personal computers, data centers and communication equipment, this impact also includes the water use and land impact from mining, building and distributing the metals and other materials that make up our vast global digital infrastructure.

Many researchers have attempted to calculate the individual carbon footprints of various technologies, and these often focus on the energy used by servers, home wi-fi and computers and even a tiny share of the carbon emitted to construct data center buildings.

Some of our greenhouse-gassiest digital activities include:

• Video calls: Just one hour of videoconferencing can emit up to 1 kg of CO₂, require up to 12 liters of water and demand a land area adding up to approximately the size of an iPad Mini, according to recent research from MIT, Purdue and Yale University—but switch off the camera and you'll save over 98 percent of those emissions.
• Emails: Professor Mike Berners-Lee calculated that a short email sent phone-to-phone over Wi-Fi equates to 0.3 grams of CO₂, a short email sent laptop-to-laptop emits 17g of CO₂ and a long email with attachment sent from laptop could produce 50g of CO₂.
• Digital hoarding: Data transfer and storage of thousands of photo, audio and video files, messages, emails and documents in an average US data center emits around 0.2 tons of CO₂ each year, for every 100 gigabyte of storage.
• Binge-watching in High Definition: Just one hour of HD streaming a day emits 160kg of CO₂ each year—but swap to Standard Definition video quality and that drops to around 8kg of CO₂ annually.
• Using supercomputers: Australian astronomers each produce 15 kilotons of CO₂ a year from super-computer work—more than their combined emissions from operating observatories, taking international flights and powering office buildings. However, Dutch astronomers produce about 4 percent of these emissions, as the Netherlands national supercomputer uses 100 percent renewable energy.
• Artificial Intelligence: Training a large AI model emits 315 times more carbon than a round-the-world flight.

But many of these figures will change depending on things like the use of renewable energy that is being taken up by some digital corporations and many individuals.

Concepts like the paperless office, remote work and virtual conferences often come with a promise of lower environmental impacts—but experts  say these can be examples of "digital solutionism."

So they think individuals cannot be expected to resolve these issues; governments need to regulate and corporations need to act, to improve our digital future  and make it sustainable.

Jessica McLean et al, Digital (un)sustainability at an urban university in Sydney, Australia, Cities (2022). DOI: 10.1016/j.cities.2022.103746