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A Puff of Carbon Dioxide

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As appeared on London Review of Books on 19 January 2023, read here.

Dozens,​ hundreds, perhaps even thousands of online ads flash before your eyes every day, so many that you probably don’t even notice most of them. Generating the electricity to get just one ad to appear on your screen can produce a puff of carbon dioxide sufficiently large that, if it were cigarette smoke, you would be able to see it. Showing a single digital ad to a single user involves, on average, emitting between roughly a tenth and a whole pint of carbon dioxide. And the digital ad business puffs on quite a scale. No one knows exactly how many ads are shown online across the world, but informed estimates collected by the researcher Mikko Kotila suggest as many as 400 billion a day.

Many large advertisers are keen to trumpet their commitment to sustainability and the carbon neutrality of their products. Emitting lots of carbon dioxide while doing so is an obvious contradiction, and advertisers’ awareness of that has surged in the past year or so. One response can be to keep puffing away and buy an equivalent amount of carbon credits associated with emissions-reduction projects elsewhere, usually in the Global South. But directly cutting advertising’s emissions must be a better path. There’s a lot of scope for doing this: research by O’Kelley’s carbon-measurement firm Scope3 and the consultancy Ebiquity suggests that the carbon footprint of ads varies wildly, with some nearly a hundred times bigger than others.

The Hidden Cost of Digital Advertising – research report, read here.

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