Cyclists pollute more than cars, claims Swiss economist; Scary HGV close pass video sparks cycling infra debate; Why can’t all cyclist v driver clips be like this? Cyclist hits van and apologises; Arty bike stand divides opinion + more on the live blog

Hang about - you're not going to riff this into "A modest proposal" RE: the cost of living are you?

I think rich_cb is veggie or vegan (?) - hope you're not being provocative!

I try and eat very little meat but am not vege etc.

I'm fully in agreement with Ktache though, if we're going to eat meat it makes sense to eat meat with a low marginal CO2 cost. Veal as a byproduct of the dairy industry is a good example but the best is probably culled venison.

Wild venison chilli con carne is superb.

For some reason I thought you were - don't know why.  Anyway happy to help out by eating venison (I also don't eat much meat).  Us folks here in Scotland could certainly eat more deer given that it's being culled!  And likely e.g. farmed rabbit, fresh sea food etc.  I'd definitely find it difficult to give up cheese though.  I did once by fiat once living in a country with no tradition of dairy product use until recently - discovered that it was important then!  I have trained myself to use soy milk though.  (Does that make me part of the wokerati?)

chrisonatrike wrote:

I have trained myself to use soy milk though.

But what are the baby soys going to drink?

I still don't understand soy milk.  As the song says - how do you milk a bean?

https://www.youtube.com/watch?v=KHBFnx7P8GM

Rich_cb wrote:

I try and eat very little meat but am not vege etc. I'm fully in agreement with Ktache though, if we're going to eat meat it makes sense to eat meat with a low marginal CO2 cost. Veal as a byproduct of the dairy industry is a good example but the best is probably culled venison. Wild venison chilli con carne is superb.

I had a kangaroo meat burger, years ago.  In the UK.  In hindsight, I dread to think what the carbon footprint of that (very tasty) burger was...

brooksby wrote:

I had a kangaroo meat burger, years ago.  In the UK.  In hindsight, I dread to think what the carbon footprint of that (very tasty) burger was...

Kangaroos are considered pests, so I doubt that it was farmed which should help with its carbon footprint. Mrs HawkinsPeter tried kangaroo once whilst in Australia (she found it a bit tough), but I guess that flying over to Australia is far worse in terms of CO2 than getting a steak shipped to the UK (to be fair, we didn't go over there just to try a steak).

If it was shipped it probably wouldn't be too bad. Shipping is surprisingly low carbon on a per kg basis.

If it was flown it would be awful.

On that note, out of season Asparagus (air freighted from Peru) is IIRC the worst food from a CO2 per calorie perspective.

Rich_cb wrote:

If it was shipped it probably wouldn't be too bad. Shipping is surprisingly low carbon on a per kg basis. If it was flown it would be awful. On that note, out of season Asparagus (air freighted from Peru) is IIRC the worst food from a CO2 per calorie perspective.

How about celery? That's often considered to have negative calories when you factor in the chewing.

That's a good point.

To save the planet we'll all have to stop chewing our celery.

Rich_cb wrote:

That's a good point. To save the planet we'll all have to stop chewing our celery.

Luckily enough, I consume all of mine Intravenously.

To ethically eat meat, if all vertebrate lives matter equally, we should minimize the deaths per pound of meat. Therefore, we should only eat blue wales, or barring that, elephants.

At 100,000 kg, the meat of one blue whale would easily supply two cyclists for their entire lives with the required two kilos of meat per day to commute.

We'd need big deep freezers, though.

How do you feel about parasitism?  Don't need to eat the whale all at once, you could just take small chunks like a cookiecutter shark.

Not as unlikely as it sounds as several human cultures have used animals for literal vampirism (e.g. as renewable supplies of blood).

I make it 56 which might be achieved on a longer trip constant speed. But would make more sense to use a typical journey of up to 5 miles for comparison.
 

Cycling as a form of exercise does consume calories. A human burns more calories when cycling than at rest, that's just a fact. However, that's pretty much the only part of the economist's analysis that holds water - which I find pretty indicative of the accuracy (or more to the point, the lack of accuracy) of economic analysis.

Is it?

From a carbon perspective you're probably better off taking certain forms of public transport than cycling.

Just looking at trip emissions you may even be better off sharing a car for some trips too.

Rich_cb wrote:

Just looking at trip emissions you may even be better off sharing a car for some trips too.

But that's the problem, looking at just trip emissions (and I'm somewhat dubious of those numbers), you're ignoring all of the externalities that absolutley contribute to the carbon footprint of driving.

E: and as pointed out in the main blog - walking is less efficient in calorie use than cycling, so if you honestly think that cycling five miles is worse for the environment than driving five miles, then you must also think that walking five miles is worse than both? C'mon, really?

Not just that, the 12kg is just for burning fuel so that is being compared with the footprint of food production ignoring the footprint of fuel production and delivery.

It depends on how you look at it.

Driving a car yourself for a short trip will never be less carbon intensive than walking/cycling.

Sharing a trip is a different matter.

If a vehicle is already travelling where you want to go then the marginal cost of carrying an extra passenger is minimal in carbon terms.

Eg Carbon cost of a 10km journey in a car is x kg CO2.
Carbon cost of same journey with an additional passenger is y kg CO2 the marginal cost of catching that lift is y-x. This is likely to be very low even for a car. For a train it's going to be absolutely tiny.

Most of the calculations simply divide the entire x by number of passengers which isn't always appropriate.

This is all true. However, you'd then need to consider whether the car trip has to be a car trip (and the whole argument sort of relies on that assumption) - if not, you should be comparing four people on bikes going 10km vs four people in an car of "average fuel efficiency". Otherwise, what you're doing is saying that the only one who has any significant carbon footprint is the driver who has decided to make the trip by car, and the three passengers are almost irrelevant. Then, the only way you're making the comparison favour the car is by ignoring the driver and comparing the cyclist to one of the passengers. I think that's maybe a little disingenuous.

In your example, say you want to go the park and you spot a car with three people in it being driven to the park (that, for some reason has to be a car journey), so you flag it down and jump in. In this case, you're right in saying that the weight of the extra passenger has a minimal effect on carbon emissions (though whether this is less than cycling the same trip depends on the car - you can't just assume, as the professor has done, that the car in question is unreasonably fuel efficient compared to the average car).

However, this is a somewhat far-fetched example. In reality, it's going to be four people who have made the joint-decision to take the car. In this case, you have to consider whether the journey has to be made by car. Then, you are dividing the "x" number by the number of occupants (along with all of the other externalities of the car - you can't count the production/transport of the cyclist's fuel and ignore the production/transport of the car's fuel, you have to consider the impact of the car existing in the first place compared to the bike), and compare this to the four of them cycling to the park instead.

I think the above is a case of altering the scenario (or at least being a little selective with its variables) to make it fit the hypothesis, and to do so, you’d have to remove any resemblance to how these things work in reality.

I do agree but I don't think the necessity of the car journey is that relevant.

What matters is that the car journey will take place regardless of what you, as a potential passenger in said car, decide to do.

The CO2 cost of your journey is therefore marginal and worked out in comparison to the cost of the journey taking place without you. In that way it's directly comparable with public transport.

If there is public transport running in the direction you want to go the marginal CO2 cost of cycling will always be higher than the marginal CO2 cost of taking the already running transport.

For a car it will depend on the efficiency of the car but it would have to be a pretty inefficient car to have a higher marginal CO2 cost.

Whilst dietary choice will impact marginal cost of cycling I doubt even the most carbon efficient diet could compete with public transport marginal costs.

Rich_cb wrote:

I do agree but I don't think the necessity of the car journey is that relevant.

I think this is the sticking point where we're probably not going to agree.

The comparison (in my opinion) is car vs bicycle. That is, is it better for four people to cycle than share even an economical car (spoiler: yes). The comparison you're making is car vs car AND bicycle, which is a different story, because it relies on a car journey (that, for some reason must be a car journey) going exactly where you want, when you want, full of people that don't mind you just randomly hopping in, and it still ignores the externalities of driving, fuel production, ect. This isn't (in my opinion) a real-world scenario. Also, the whole point of the "we should cycle more, it's better for the environment" argument is to reduce the amount of these car journeys that would be happaning anyway.

I think this is re-framing the argument in a way that's unfair to the bike, because what I'm saying is it's better to have four million bike trips instead of one million car trips (which is true), and what you're saying is it's worse to have one million bike trips as well as one million car trips (which is probably also true - though it sort of depends on the diet discussion we had earlier).

Your argument does map better to public transport, but there are still other considerations to be made - Public transport journeys aren't A-to-B, they're A-to-Z (I don't live anywhere near a bus stop now, but in my old village, a trip to town wasn't a 2 mile bike ride vs a 2 mile bus trip, it was a 2 mile bike ride vs 10 mile bus trip). Public transport are less efficient vehicles - yes they are often shared between many people and this brings overall efficiency to be much better than private cars, but they're often not full, so you have to consider the impact of an old deisel bus driving around with nobody on it, and there are still the other externalities of driving. 

I think we'll probably have to agree to disagree on this one, but I'll concede that you've made good arguments on the dietary impact of cycling, and that cycle journeys do have a larger carbon footprint than many assume.

I would disagree that it's an unlikely scenario.

If you work somewhere pretty big it's quite likely there will the opportunity to share a ride to and from work. This has certainly been the case for me many times.

In that situation the marginal cost is the main focus.

I do think agreeing to disagree is probably the best outcome here though. Thanks for an interesting discussion.

Rich_cb wrote:

I would disagree that it's an unlikely scenario.

It's not impossible, but as others have pointed out, the average car occupncy in the UK is 1.5 people. So, generally speaking, it's not guaranteed for a car to have two people in it, let alone four.

Going back to my "trip to the park" example, the argument is based on "adding" a cycle journey to a car journey that would be happening anyway - in which case the "marginal cost" of the cyclist hopping in the car is negligable (providing that you view the carbon footprint as being "owned" by the driver, and the three passengers being marginal additions - which I'm not sure I'm on board with). When viewed this way, it makes the cycle ride look like a bad choice, environmentally speaking. However, the reality of the stiuation is that the cycle ride is likely to replace one of four seperate car journeys.

Statistically speaking, cycle rides in the UK are likely to entirely replace single-occupancy car journeys, and that (I think) is where we're disagreeing. You made another comment talking about personal costs vs aggregate, systemic costs which I agree with 100%. I think you're arguing the "personal" side ("I'm just going to hop in this car that's already going where I want, the driver's creating the carbon cost, I'm just along for the ride"), and I'm arguing the "systemic" side ("it's better to replace that car with two bikes").

But it has been an interesting discussion, and if anything, we've proven that (contrary to what some say) people can disagree respectfully on this site.

If you look at the modal share of transport in Amsterdam whilst cycling appears to have displaced a lot of car journeys relative to other major cities it has also displaced quite a bit of public transport by the same comparison. Example Vs London below.

Cordial disagreement indeed!

Ah, but what if you're a cyclist who powers themselves by foraging for berries, nuts and road kill?

The marginal CO2 cost of road kill and foraging is probably negative so you can cycle to your heart's content.