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ScienceMay 6, 2024

The climate cost of your digital life


How worried should we be about the cloud?

This is an excerpt from our weekly environmental newsletter Future Proof. Sign up here.

I currently have a few thousand unread emails languishing in my inbox, mostly old marketing newsletters and piles of unread science journal press releases. I have a similar number of photos backed up from my phone: screenshots, sunset snaps, and many, many pictures of my dog.

Collectively, everyone’s data adds up. We’re creating content at a mind-boggling pace and scale: 54,000 photos are taken every second, and this year we’re estimated to create around 120 zettabytes of data. By 2035, data creation is predicted to exceed 2,000 zettabytes. Printing out just one zettabyte would require paper from 20 trillion trees (except we only have 3.5 trillion trees on Earth), or would fill more than 212 billion standard DVDs.

Much of our digital information exists in the “Cloud” – which sounds like an airy, non-physical concept, but in reality is a very physical, very large hard drive somewhere: in a data centre stuffed with servers. These data centres require electricity to power them and (often) water to keep them cool. Millions of servers become e-waste every year. This means that all your digital memories have an environmental cost, as Shanti Mathias points out in this excellent story.

Consuming data also has a carbon cost. Video streaming takes up the lion’s share of the world’s digital footprint: one hour of watching Netflix emits about 55g of carbon in Europe – a figure that varies widely between users based on the mix of renewables/fossil fuels powering the electricity grid, the resolution you’re watching at, and what sort of device you’re using to watch.

Data centres are responsible for about 1% of the world’s energy-related greenhouse gas emissions, according to the International Energy Agency. Another estimate puts the carbon footprint of the internet and all its associated gadgets as bigger than that of the airline industry. One silver lining is that the energy efficiency of data centres and devices has improved rapidly, meaning energy demand hasn’t ballooned in-step with the data boom.

Here in New Zealand, Mathias notes, data centres mostly use renewable energy. But if you use an international service like Google, your selfie photoshoots and email archives could be stored in a data centre powered by fossil fuels. As more companies look to build data centres in Aotearoa – including global behemoths like Amazon – we face challenges including water use and growing our renewable energy capacity to keep pace (not just with data needs, but with electrification of other things like transport). The incipient artificial intelligence revolution is set to send the digital economy’s carbon emissions into overdrive, too.

What does this mean for me, and you, as senders of emails and snap-happy smartphone photographers? You can go on a cathartic deleting spree (which has the added bonus of extending the life of your gadget) but really, the climate impact for an individual is pretty negligible. Even streaming your favourite show is a fairly low-emitting activity, in the scheme of emitting activities.

Nonetheless, I think there’s something valuable about being more considered in our digital habits: deleting the duds and only keeping the best, unsubscribing from emails that encourage us to buy, buy, buy, unscheduling Zooms that could be emails instead. And more often, simply switching off.

Keep going!