Cycling is better than walking (or car sharing) when it comes to saving the planet finds study

David9694 wrote:

really not sure why we're even debating this one...

Because the msm will use it to try to undermine cycling's green credentials; when they get around to noticing cycling at all that is.  Has there been any coverage of Bike Week?  I've seen none.

visionset wrote:

Nobody is a zero emitter, but active travel, esp cycling is the most efficient from a calorie per mile measure.  Petrol/diesel is far more inefficient.  And whilst engaged in active travel those calories aren't ending up clogging arteries that then have to be processed by the NHS at huge expense to us all.

Exactly.  If the journey is going to be made, then the most efficient form of transport should be used, which is inevitably the bicycle for short trips.  A point which seems to have completely escaped the notice of the authors of this study.

It's the dragging around of a fairly pointless one and a half tonnes of stuff that gets me.  I have a relatively heavy bicycle, but it still weighs less than an "executive" car seat.

eburtthebike wrote:

Exactly.  If the journey is going to be made, then the most efficient form of transport should be used, which is inevitably the bicycle for short trips.  A point which seems to have completely escaped the notice of the authors of this study.

The study found exactly that Burt.

The bicycle was the most efficient.

Did you even read it?

Good work.

For me, that is the 'take home message' from the study.

Eat locally grown seasonal food as much as possible.

Up until a few years ago I was pretty oblivious to the environmental impact of the food I was eating. Studies like this definitely help to educate people as to the impact of their choices.

If that's the take-home message, doesn't it suggest that the results of the actual study, which was meant to be about the impact of different modes of travel rather than different diet choices, were indeed rather meaningless?

The study estimated the carbon footprint of cycling for different diets.

So the take home message for a cyclist is that the carbon footprint of your cycling is directly related to your diet.

Broadly speaking locally grown seasonal food has a lower carbon footprint. Bananas apparently being an exception!

I think bananas are generally transported by container, and many other fruit and veg that doesn't completely rely on freshness, and the reduction of picking to plate.

Container freight is shockingly efficient and cheap.  The size of todays massive container shops allows such efficiency of scale.  I heard on some TV programme, perhaps apocryphal, that it was cheaper to ship a pair of jeans, port to port, from China than it was to distribute them from the port by road, in the UK.

A lot of that cheapness will be savings in fuel, shockingly dirty that fuel oil is that they burn on those huge container ships.

Flying anything is incredibly fuel inefficient, most of that, as I understand it, coming from getting it up there.  I remember, when I was temping in the mid 90s, when working nights for Geest at Heathrow, Kenyan sugar snap peas and fine beans would come in, already prepacked in small cellophaned polystyrene trays.  Never really appealed to me as a consumer, I want cheapish, substantial veg when I'm cooking and eating it.  Only job I ever worked with electric pallet trucks, fun, though a little scary when working that tired.

ktache wrote:

Flying anything is incredibly fuel inefficient, most of that, as I understand it, coming from getting it up there.  I remember, when I was temping in the mid 90s, when working nights for Geest at Heathrow, Kenyan sugar snap peas and fine beans would come in, already prepacked in small cellophaned polystyrene trays. 

Life usually being way more complex than it appears, sometimes means that simplistic and usually context free food miles can be a terrible way of judging something's green credentials. Surprisingly, it can be greener to grown fine beans in season in Kenya or wherever than to do so out of season in UK.

Especially as they are generally barred from using drive-throughs ...

Whereas I eat the cakes and pasties in case I have to commute one day.  Preperation and all that.

I just eat the cakes and pastries (and pasties) because cakes and pastries (and pasties). My cycling is entirely coincidental.

grumpyoldcyclist wrote:

Trust the Daily Mail, or rather don't....

Couple of observations if I may be so bold; a 25 stone sedentary driver, is likely to eat more than a 10 stone cyclist as the driver has a huge metabolism to support which consumes calories despite them being inactive.
Secondly the Daily Mail completely ignores the point that extra walking, which may involve extra calorie 'use',  will greatly lower the possibility of disease (diabetes, obesity, cancer, stroke, heart attack etc etc etc) and therefore 'Protect the NHS'. How quickly recent lessons are forgotten.

The mamils who drive their SUV miles before starting a ride to the cafe for a gourmet civet espresso & half a cake might be feeling a little less virtuous. Though hopefully they might have forgotten about the cake stop by now, and be benefitting from a lowered BMI?

kt26 wrote:

If we are going to attribute walking/cycling with the carbon footprint of increased food intake - we make the assumption that a gym session (which one might drive too) isn't being replaced with an Active commute.

We also make no allowances for the carbon impact of a sedantary lifestyle - I very much doubt it is negligible.

These are 2 factors that certainly undermine their assumption. A few thoughts:

Is the driver assumed to be using zero calories from their diet for their journey? And not stopping at McD or wherever for a throwaway cup of brown water on their way to work? (with engine idling in the queue at the drive-thru)

Those who drive daily are likely to replace their vehicle much sooner than the regular cyclist whose car may be used less often. Households with 1 or more cyclists may have lower car ownership rates.

Is the active commuter's diet that much larger than the driver? How do you establish the energy use of a cycle commute? And does some of their diet not come from staples such as bread, potatoes, oats, rice and pasta? All cheap sources of energy and likely low in CO2 per kg.

Beyond their own health, what about the driver's negative impact on the rest of society including noise, pollution (15 million in the UK exposed to "the invisible killer" says the BHF) and casualty statistics?

This graphic from a few years ago suggests that walking and cycling have a net benefit to society while buses and cars cost society quite a lot:

https://averagejoecyclist.com/wp-content/uploads/2016/03/infographic_2_s...

I have printed the report PDF to read over the weekend and would be interested in further observations.

The driver is not assumed to be using zero calories. They are assumed to be using no more than if they were equally sedentary elsewhere.

Whereas a cyclist will be burning more calories than if they were sedentary.

If you own a car then unfortunately you are responsible for some of the carbon footprint of that car even if you never drive it.

All other things being equal, a car owning cyclist has a far greater carbon footprint than a non car owner.

The paper examines the impact of a range of diets, that's pretty much the point.

If you dine exclusively on Peruvian asparagus then your carbon footprint is going to be enormous regardless of what transport you take.

You just don't get science do you Burt?

I haven't read this particular paper but the original Berners Lee book tried to assess all forms of transport on the basis of how much energy from the sun (whether converted via solar panels into electricity, via fast-growing wood - willow? - into renewable fuel, or via wheat bread into pedal power) each took. So I don't think he was making specific assumptions about how much more a cyclist might eat, more measuring the energy input required to move a bike over a given distance. 

I've had a quick read of the paper and a couple of the references they cite and I cannot see any figures for increased calory intake in any of the studies, either from self reported figures or lab studies, any conclusions are therefore based on an untested assumption. There have however been studies, the study comparing calorie requirements of the Hamsa[I think that was the tribe) and New York office workers springs to mind, that suggest that with increasing fitness comes increasing physiological efficency, ie that non competitive but physically active individuals have calorific requirement similar to largely sedentary individuals.

While it is obvious that cycling a mile requires fewer calories than walking or running a mile, until there are some controlled studies to determine how much a comuting walking or cycling persons calorie intake increases studies such as this are, largely, meaningless.