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| Source: Bloomberg |
A common comment I get from denialists is "if you care so much about global warming, why are you still using a smartphone/laptop"?
OK, so just how much power do smartphones and laptops use?
It takes 1 kWh of electricity to power your smartphone for a year, and 72 kWh to power a laptop for a year (it uses much more because the screen is bigger). Now, the average US utility customer uses 10,766 kWh per annum. Let's assume each household has 3 smartphones and 3 laptops. That means that using these devices consumes 2% of total electricity demand in the US. OK, but what about making the smartphones and what about the energy used by data centres?
From The Conversation:
Having conducted a meticulous and fairly exhaustive inventory of the contribution of ICT —including devices like PCs, laptops, monitors, smartphones and tablets — and infrastructure like data centres and communication networks, we found that the relative contribution of ICT to the total global footprint is expected to grow from about one per cent in 2007 to 3.5 per cent by 2020 and reaching 14 per cent by 2040.
That’s more than half the relative contribution of the entire transportation sector worldwide.
In absolute values, emissions caused by smartphones will jump from 17 to 125 megatons of CO2 equivalent per year (Mt-CO2e/yr) in that time span, or a 730 per cent growth.
The lion’s share of this footprint (85 to 95 per cent) will be caused not by the use of the device, but rather by its production. That includes, in addition to the manufacturing energy, the energy for material mining for gold and the so-called rare-earth elements like yttrium, lanthanium and several others that today are almost exclusively available only from China.
Another guilty participant in this excessive carbon footprint are the phone plans that encourage users to get a new smartphone every two years. That accelerates the rate at which older models become obsolete and leads to an extraordinary and unnecessary amount of waste.
On the infrastructure side, we predict the combined footprint of data centres and communications networks will grow from 215 megatons of C02 equivalent a year (Mt-CO2e/yr) in 2007 to 764 MtCO2-e/yr by 2020, with data centres accounting for about two thirds of the total contribution.
Sounds bad, doesn't it? Yet most datacentres are switching to renewable power: Google has switched to 100% renewable energy, as has Apple and Amazon. Total global CO2 emissions are roughly 40,000 megatonnes (Mt) of CO2, which means manufacturing smartphones will add 125/40,000 or 0.3% of total global CO2 emissions. If datacentres weren't providing their own green power (and most are) that would add another 764/40000 or 1.9%. (I'm not sure where the author of the piece in The Conversation gets the 3.5% by 2020 quoted above)
Of course, the people who sarcastically point out that those of us who argue for a greener world are adding to the problem by using smartphones don't in fact really care. They're just trying to score a point, along the same lines as "Al Gore flies the world a lot, adding to carbon emissions, so he's a hypocrite."
What can you do? Don't buy a new smartphone every 2 years. Mine is 4 years old, and my laptop is 5. They work just fine, and a new battery is now ridiculously cheap.
And, by the way, if you want to do what you can, eat less meat and dairy. Livestock production contributes 15% of global greenhouse gas emissions. Oh, and don't vote for denialist political parties (Hint: Republicans in the US and the L/NP coalition in Australia.) The world's steadily rising temperatures will lead to disaster unless we stop emitting carbon dioxide and methane, as soon as we can.
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