Do any of these calculators account for all the energy needed to create and support the infrastructure needed for cars? The comparable infrastructure for bicycles would be a tiny fraction of that.

I think some calculations do try to factor in indirect energy. But it's a pretty complex equations. You have the cost of fuel. But you also have the cost of maintaining armies to protect your fuel. You have the cost of refining gasoline, but how do you make an estimate of the cost of damage to the environment you live in? I'm guessing it's a bit overwhelming trying to figure it out.

I think some calculations do try to factor in indirect energy. But it's a pretty complex equations. You have the cost of fuel. But you also have the cost of maintaining armies to protect your fuel. You have the cost of refining gasoline, but how do you make an estimate of the cost of damage to the environment you live in which you've sort of transferred to another generation?

I'm guessing it's a bit overwhelming trying to figure it out.

Hello,

I too have just read 'How Bad Are Bananas: The carbon footprint of everything'. Page 23 is where it claims that cycling a mile is responsible for a minimum of 65 grams of co2 - that being the carbon footprint of the banana you would consume to cover that distance.


But clearly this doesnt make any sense because cycling 1 mile wouldnt actually require the consumption of anything at all, not when it's only 3 or 4 minutes of exercise. So i'm trying to work out a more accurate figure for emissions per mile so i can present the information to the author of the book. When i do my long ride at the weekend, it is usually about 60-80 miles and I take with me 1 banana, a protein bar, and two bottles of psp22. My water bottles are 1 litre capacity and they have about 75grams of psp22 in each one. So i'm probably getting through 3 grams of psp22 per mile, at an endurance intensity with a corresponding HR of about 140bpm.



If you know of anyone who has worked out the carbon footprint of sports drinks and energy bars that would be very helpful.



I'm also interested in knowing more about the carbon footprint of the materials that go into making a bike. Im more of a traditionalist myself and like a steel frameset with lugs, but i wondered if a hand-made steel frame from a small local framebuilder is better for the environment than a carbon-fibre frame from a factory in China?


I dont expect to ever reach a conclusive figure because there are so many variables, but good accurate information would be very useful.

Thanks.

In one sense, CF (like all plastics made from petroleum) actually sequesters carbon from the atmosphere. That means that the carbon that goes into the bike frame can't go into the atmosphere and therefore can't contribute to climate change. I believe that steel also contains some carbon, but it probably wouldn't be sequestered for as many years as the carbon in CF.

The whole cycling thing is a red herring. Clearly active and fit people will consume more, irrespective of whether they cycle or drive. I don't think that anyone would argue that we should attack sustainability and carbon emissions by striving to be as sedentary as possible. All the author is really saying is that Cheeseburgers have a high carbon footprint.

Meat is notorious for it's high carbon foot-print, but that's also because Americans eat far more meat than is nutritionally essential.

In regards to biking on a cheeseburger, you could make the model even more complex by comparing the relative health of a cyclist and a driver, and factor in how much carbon is used to feed and transport the doctors that gave them the triple bypass, fed the scientists and engineers that had to design the stint, the list goes on.

For even more complexity, while meat is an energy intensive food to produce, but it is also a generally highly efficient food source (your body uses 64% of the protein in tofu, while it uses 74.3% of the protein in beef, and can use a whopping 96% of the total protein in whey). So if soy is 2/3 as efficient a nutrient source as whey, you would need to eat 1.5 times as much tofu as whey to get the same nutritional value.

The short of this is these books do quick and dirty calculations the more reflect the assumptions of the author than the intricate and complex reality of the situation.

I think the last two posts really got to the meat of the issue.

Carbon emissions are not the end all be all of everything though. Something that for some reason a lot of people seem to be oblivious to.

Think about the bike Vs. a car. 4000lbs. of material vs. 20-25lbs. of material. Think about tires. Most scrapped tires are burned. Then you have batteries - actually modern car batteries can be recycled in their entirety, but a whole lot of older ones cannot be. Used motor oil? Some of it is recycled. Some of it is burned. Some of it leaks into the ground.

It's a lot more complicated of an issue than fuel in, emissions out.

Cars require magnitudes more materials - thousands of pounds of metal, hundreds of pounds of rubber, and exhaust isn't the only pollution a motor vehicle makes.

I think it would be exactly that simple. But the problem is figuring out all the inputs. Of course, bicycles are wonderful machine, but they will use some fossil fuel in their manufacture and of course parts do wear out.

Not only that but the energy to ride is not free. If you do a century ride some day, you'll probably notice the difference when you sit down for dinner and starting inhaling your food.

Nonetheless, in terms of bang for the buck, a bicycle is an almost perfect distance vehicle.

The original premise is stupid. The 2 people in the car also ate a cheeseburger - they just got in a car instead of riding a bike. They wasted the cheeseburger energy because it was either turned to fat or excreted. It also ignores the carbon footprint of manufacturing the car verses manufacturing the bike.

Yes, the industrial food system is wasteful. That point could be made in a much better way. Also, a vegan diet isn't always the "greenest" diet although it usually is when strictly talking about industrial civilization. Hunter gatherers that kill their own meat are much greener than any vegan munching on slabs of tofu.

I'll remember this thread when I meet a motorist who doesn't eat any food at all.

I'll remember these posts next time I eat a motorist