The cloud has a physical cost

Every time you run software, something physical happens: a machine somewhere draws electricity, and water goes into keeping it cool. AI has pushed both up sharply. The useful part for you is that where and how you run things changes the footprint, and running leaner usually shrinks it.

The footprint is larger than most people realise

The scale has grown fast enough to become a mainstream concern. A 2026 report from the United Nations University found that data centres’ environmental footprint already rivals some of the world’s largest countries, and it expects their energy and water use to roughly double within four years as AI grows. On electricity alone, the report projects data centres reaching around 945 terawatt-hours a year by 2030, with AI the main driver. Over the same period, AI goes from a small slice of that demand to a large one.

Where the cost lands

It lands in two forms. The first is electricity, drawn from grids that are still partly fossil-powered, so a busy data centre carries real carbon emissions. The second is water, used to cool the machines: the same report put data centres’ water use at roughly 4.5 trillion litres last year, and that demand climbs in hot weather, which is exactly when the surrounding area is most likely to be short of water too. These costs are real, and worth understanding rather than waving away.

The good news: running lean shrinks the footprint too

The choices that shrink an environmental footprint are mostly the same ones that cut waste in general, so you’re not trading one against the other. A few worth looking at:

• Switch off machines sitting idle. Compute left running through nights and weekends burns power for nothing.

• Right-size before you scale up. A smaller machine that does the job uses less of everything.

• Choose your region with care. Providers run different regions on cleaner or dirtier grids, and they publish the figures, so the greener choice is usually there to see.

• Run heavy jobs when it makes sense rather than the instant they’re queued, so capacity gets used well.

A fairer, more transparent cloud industry means being honest about this part too. The footprint isn’t a reason for guilt, and no single company fixes it alone. It’s worth understanding, and paying attention to it tends to leave you with a leaner setup as well.