Your code runs somewhere. At Grade 11 that was a laptop; by the time anything you write is used by strangers, it is a rack in a building that draws power continuously and is cooled continuously. The environmental question stops being about the device on your desk and starts being about the system you designed.
Where the cost actually sits
- Manufacturing. Most of a device’s lifetime carbon is spent before it is switched on — mining, refining, assembly, shipping. Which is why a repaired five-year-old laptop beats a new efficient one, and why “upgrade the fleet to save power” is usually arithmetic that does not work.
- Running the servers. A request that takes ten times as long costs roughly ten times the energy. Efficiency is not only a user-experience concern — it is the environmental one, which makes Efficiency and Big-O a sustainability topic as much as a performance one.
- Cooling. A large fraction of a data centre’s power removes heat rather than doing computation. Where the building is, and what its power comes from, matter as much as what runs inside it.
- End of life. Electronics carry lead, mercury, and cadmium. In landfill those reach soil and water; in informal recycling abroad, people.
- Human health, at the desk. Repetitive strain, eye strain, posture, sleep disrupted by late screens, and the effects of being permanently reachable. These are occupational health issues in this profession, not lifestyle advice.
What a developer can actually change
| Decision | Why it matters |
|---|---|
| A better algorithm | The largest lever you personally control; an solution where an one was doing costs orders of magnitude less energy at scale |
| Cache what does not change | Work not done costs nothing |
| Batch and schedule | Overnight jobs can run when the grid is cleanest |
| Send less | Smaller payloads, fewer round trips, images sized for the screen |
| Do not poll | Waking a device every second to ask “anything yet?” is a battery bug and a server bug |
| Support old devices | Software that forces hardware replacement has an emissions cost you caused |
Programs and agencies that exist for this
In Ontario, end-of-life equipment has a settled route, and there are organisations whose whole purpose is to keep working machines working:
- Recycle My Electronics / EPRA Ontario — the approved provincial electronics recycling program, free to residents at approved depots, overseen by the Resource Productivity and Recovery Authority.
- Renewed Computer Technology, which delivers Computers for Schools Plus in Ontario — refurbishing donated equipment for schools, libraries, non-profits, and low-income households, with paid youth internships doing the refurbishment.
- Municipal hazardous- and electronic-waste depots, which take what retailers will not.
- Environment and Climate Change Canada and the Ontario Ministry of the Environment, Conservation and Parks for the reporting, regulation, and data behind any claim you want to make.
Details change — programs are renamed and rules rewritten — so verify against the current source before you cite any of it, including this page.
The honest counterweight
Computing also makes environmental work possible: climate models, sensor networks, grid optimisation, precision agriculture, routing that removes kilometres. Both things are true at once, and a report that gives only one side is not finished. The Efficiency Case is where you have to hold both.
Curriculum connection
D1.1
outline strategies to reduce the impact of computers and related technologies on the environment (e.g., reduce, reuse, and recycle; turn computers and monitors off at end of day; participate in printer cartridge recycling) and on human health (e.g. ergonomic standards);
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D1.2
investigate and report on governmental and community initiatives that encourage environmental stewardship and promote programs and practices that support sustainability (e.g., local community recycling centres, private companies that refurbish computers, printer cartridge recycling programs).
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