Thread by @simon_brooke

I have a diesel car, which has run 145,000 miles. Which would be the most carbon-efficient thing to do: run it for another 85,000 miles, or scrap it and buy a new electric car and run that 85,000 miles? The answer is not simple.
#ClimateEmergency >>>

(Actually, there is a simple answer, which I shall come to later). >>>

The average car in the UK is currently driven about 8,000 miles per year; so 85,000 miles is about ten years use.
nimblefins.co.uk/average-annual…

>>>

Burning diesel emits 10.9 kg of carbon per gallon; my car does more than 50 miles per gallon, on long term average. So in 85,000 miles it will emit 18.53 tons of carbon.

>>>

The carbon emitted in the manufacture a medium sized fossil-fuel car is about 17 tons.
theguardian.com/environment/gr…

>>>

But to manufacture the battery of an electric car costs a further ton of cabon, taking us to 18 tons.
ucsusa.org/sites/default/…

>>>

So over 85,000 miles, the carbon cost of a new electric car is the same as keeping an old diesel running.

>>>

But the simple answer is simple: we cannot afford for us each, individually, to emit 1.8 tons of carbon from personal transportation every year.

>>>

I cannot find any estimates of the carbon cost of manufacture of an electric assist pedal cycle, but the materials used are the same as the materials used in cars, and to produce a given mass of a given material will require a given amount of carbon.

>>>

If a medium sized electric car weights 1.8 tons and costs 18 tons of carbon to manufacture, that's roughly 10 tons of carbon per ton of finished weight; so an electric-assist cargo bike weighing 35Kg will have a carbon cost of 350kg.

>>>

So an electric assist cargo bike has a carbon cost of LESS THAN TWO PERCENT of an electric car.

>>>

You can't use a cargo bike for all the journeys you can use a car for; but, realistically, you can probably use it for 80%. 10% of the rest, you can use public transport. For the remaining 10%, you may have to hire a car.

>>>

But that, essentially, means that is we all replace our cars with cargo bikes (or vehicles with the same mass as cargo bikes) we have a carbon cost per year of

35Kg +
180Kg car hire +
170Kg public transport =
385Kg

>>>

So that reduces our personal transport footprint by 80% - down to 20% of the carbon cost of an electric car. But there are other benefits.

>>>

Urban roads will be a lot less congested - a bicycle, even a cargo bike, takes up far less road space than a car, when moving or when parked.

It's also far quieter and far less likely to cause injuries.



>>>

We can't all replace our existing cars with new electric cars: the planet cannot afford the carbon cost of manufacturing them. But that doesn't mean we need to greatly reduce our personal mobility.

Go buy bike!

>>>

(For comparison, one round trip from the UK to Australia for one person by air costs about SIX TONS of carbon - if you're even considering going on holiday by air, please murder your children first. It's kinder.)

theguardian.com/environment/ng…