Thursday, 19 December 2013

When driving becomes greener than cycling...

Photo by Andrew Dressel
Two men fed with cheeseburgers cycling a mile would have a similar carbon footprint if they were together in a car driving the same distance. Or at least this is the conclusions Mike Berners-Lee draws from his expertise on carbon footprints.

In his book 'How bad are bananas', Mike Berners-Lee gives us a overview of the carbon footprint of everything and while the book clearly makes a point about not fighting pointless battles -like using an electric hand dryer vs. paper towels-, he clearly shows how much the food we eat can impact our environment.

For example, the carbon footprint of cycling a mile varies drastically depending on the food you are running (cycling) on:

  • Bananas: 65g (CO2e)
  • Cereals with milk: 90g (CO2e)
  • Bacon: 200g (CO2e)
  • Cheeseburgers: 260g (CO2e)
  • Asparagus from Peru (air-freighted): 2800g (CO2e)

He based his calculations on the assumptions that you burn 50 calories per mile. This is just an assumption and it is obvious that figures will vary with your weight, your fitness, speed, terrain and how much you brake. Although these factors impact how much energy you consume, it does not impact how green your food is.

In his CO2e calculations, he takes into account the footprint of all CO2e producing steps involved between growing your food and your plate, including greenhouse heating, cow farts (methane emissions), packaging, freight ...

All this does not mean that cycling is damaging to the environment, especially if powered by bananas or cereals which are nearly 10 times more carbon-efficient than the most efficient petrol powered cars.

So why are bananas so efficient?

  • Grown in natural environment (no heated greenhouse)
  • They keep well and can therefore be transported by boat over long distances (most efficient transportation)
  • They need very little packaging

If you however decide to ride around burning Peruvian a asparagus calories... you should just remember that it corresponds to thirsty car consuming 6 miles/gallon (~1 litre/km) ... and you would be making the environment a favour by switching to a Hummer.

More details on this article and I strongly recommend reading the book as it is full of similar enlightening facts... and while we're at it... if you don't want to buy it (to be greener) you can always try to catch the copy I released into the wild (via Bookcrossing).

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