alioth wrote:
a 90kg (obese) rider
A typical length 90 kg male will be a bit overweight, but not obese.
How does CO2 produced from food, (origin photosynthesis), have any effect on the atmosphere? It’s returning the carbon recently extracted by photosynthesis.
Burning fossil fuels is returning carbon to an atmospheric level of millions of years ago.
How does CO2 produced from food, (origin photosynthesis), have any effect on the atmosphere? It’s returning the carbon recently extracted by photosynthesis.
Burning fossil fuels is returning carbon to an atmospheric level of millions of years ago.
By the time it gets to your mouth, you’ve burned quite a lot of fuel to make fertiliser and plough fields and process the food and put it on a container ship to bring it half way round the earth… Animals produce a lot of methane which is a more potent greenhouse gas than CO2. So there is definitely a carbon footprint of eating and it’s fair to point that out.
However, like Alioth, the only analyses I’ve seen that show cycling as being anywhere comparable to driving in terms of greenhouse gas emissions are those that compare very optimistic driving cases with worst-case cycling (e.g. racing cyclists on a meat diet).
An 85kWh Tesla apparently has a range of 300 miles. A cyclist pootling along at 100 watts will do about 12.5mph – perhaps 8 in hilly terrain.
The energy in the Tesla battery pack would power the cyclist for over 7k miles in hilly terrain or 10k on the flat. A 250 watt cyclist will to about 3-6k miles on the same amount of energy. It’s a back-of-the-envelope calculation, and you can argue about the % of usable energy in the battery pack and other trifles, but cycling is so efficient compared to driving that you really have to fill the Tesla with people to get the maximum passenger-miles and then assume unrealistically bad scenarios for the rider’s diet in order to make the bike appear worse than a car environmentally.
And as pointed out, I think it’s fair to say that if you cycle regularly and moderately, you become fitter than you previously were, but don’t seem to change your diet significantly. I actually do think you can lose weight with regular moderate exercise, so you also reduce your basal metabolic rate (obese people have a higher metabolic rate than slimmer people) which will mean that you are living more efficiently when you are not cycling.
alioth wrote:
using a 90kg (obese) rider
Obese? In which case I should probably consider myself terminally ill… (116 kg) but actually got back my Medical Class II recently without a problem? Interesting that Body Shaming has now made it into the CO2 discussion…. but not astonishing. It’s long been one characteristic of the CO2 crowd that in the end, by sheer existence, everybody is guilty. Sounds a bit like religion to me… guilt – retribution via sacrifice – more guilt – retribution via more sacrifice. Where does it end? Do we all have to become vegan cyclists with eating disorders in order to satisfy the green crowd? Or in the end is collective suicide the way to save the planet?
alioth wrote:
I find that dubious in the real world, and using a 90kg (obese) rider also a dubious way to try to prove the point.
It depends heavily (pun intended ;-) ) on what point is actually there to prove!
I don’t really care if a Ferrari, a Honda or a VW is actually better or worse than driving by bike. The point is just, that there is no free lunch in carbon emission. And the point is even more, that far too many people stop thinking if they see something they want to believe and seems plausible to them.
If you’d ask any climate evangelist “is it better to travel by bike or by car” they won’t even take the question seriously, because in their political frame of reference it is so obvious that a car has to be bad and a bike is good, that they can not imagine anything else.
In reality, however, the answer to this question is for sure a closer call than most people think and is depending on many assumptions that do not directly have to do with the bike or car question (as your longer answer illustrates).
So even if in the end it will turn out that in a specific situation the bike is the better choice, there is a lot one can learn by (seriously) considering the question …
Mooney_Driver wrote:
Obese? In which case I should probably consider myself terminally ill… (116 kg) but actually got back my Medical Class II recently without a problem? Interesting that Body Shaming has now made it into the CO2 discussion…
That’s a purely medical term which describes the deviation from a mean weight and the associated health risks. Nothing to be ashamed of. It is you who brought up the shaming part.
I get hay fever every spring and don’t feel offended when people point it out but why are people upset about being called obese? It must be that one is self made and one is not. Like you have to feel guilty about bad teeth but not about cancer (maybe about lung cancer).
Clipperstorch wrote:
That’s a purely medical term which describes the deviation from a mean weight and the associated health risks.
And if you take it as a medical term it is just not correct that a 180cm male (avg. height of European males) at 90kg is obese.
Just because you have lung cancer doesn’t mean you smoke, just like just because you weigh 116kg doesn’t mean you are obese. Isn’t the calculation for obesity to do with body mass index. But even by that calculation many athletes would be considered obese. I remember a television programme called Gladiators, and when measured on the body mass index each of the gladiators was clinically obese.
As for cyclists, we occasionally have groups of competitive cyclists staying with us during competition or training and they eat mainly pasta not steaks.
As a Frenchman, I just don’t get veganism. I get a plant based diet and I get vegetarienism but not veganism. As I understand it, they don’t eat honey or drink (normal) wine because they rely on living beings ie bees. They don’t wear wool or any other animal product even if it doesn’t mean killing the insect or animal. I asked a vegan “what will happen to all the cows, sheep etc. If everyone became vegan” The answer was that they will eventually become extinct. Am I crazy or just French in that I really don’t understand how that will save the planet but I’m pretty sure it will make life seem longer even when it isn’t.
Clipperstorch wrote:
That’s a purely medical term which describes the deviation from a mean weight and the associated health risks. Nothing to be ashamed of. It is you who brought up the shaming part.
Well, if we are talking medical terms, the average height 90 kg male is at most in the BMI 25-27 range which is pre-adipositas by definition. If I am not wrongly informed, that BMI range is the one today regarded by most people as optimal, rather than the old school below 25. EASA defines a limit of 30 for Class 1 and 35 for Class 2.
Calling someone like that obese is questionable but fashionable unfortunately and as inappropriate as one AME years ago called me a “fat arse whose obvious lack of discipline disqualifies me as a pilot” (with a BMI of 31 for a class II exam at the time but with 120/80 bp, perfect blood figures e.t.c.). Likewise, if I see how many people are discriminated against because they do not wear fashion sizes M or S but are strong healthy human beings is hugely inappropriate as well. Obese, fat, undisciplined lout and worse is what millions of people above BMI25 have to endure day by day. Most of it quite probably in favour of a health and fashion industry which live of discrimination and selling questionable products for those undisciplined arses who will not comply to their ideals.
kwlf wrote:
(e.g. racing cyclists on a meat diet).
Which, incidentally, is entirely unrealistic. No one would eat meat to fuel for an intense bike ride, you’d end up bonking (and to be fair to the cyclist, the car you’d compare it would have to be fuelled by petrol synthesised from brown lignite coal). The “even if you eat tomatoes” is highly unrealistic too. I’ve done an imperial century ride (160km/100mi) and tomatoes were the furthest thing from my mind as something suitable to eat. If you want to fuel for aerobic exercise, most of the things you want to eat are from the bottom third of the list Malibuflyer linked ( https://ourworldindata.org/grapher/ghg-kcal-poore ), with the most CO2e “sinful” thing you’ll ever consider being bananas at 1.43kg CO2e per 1000kcal, but it’s more likely to be down around the “wheat and rye” kind of foods, at 0.59kg CO2e per 1000kcal (a far cry from 36.44kg CO2e/1000kcal filet mignon).
gallois wrote:
ust like just because you weigh 116kg doesn’t mean you are obese. Isn’t the calculation for obesity to do with body mass index. But even by that calculation many athletes would be considered obese
Oh yes, that old chestnut. Only a very tiny number of people weighing 116kg are the kind of bodybuilders who are not obese, measured in ppm population wise. Many who wheel out this phrase “but BMI and athletes” are most certainly not body builders nor athletes. Unless you’re an elite athlete or a body builder, you need to be at least 220cm tall (7ft 2in) for that to be at the high end of normal weight if you weigh 116kg. The average height of an NBA basketball player is only 6ft 6in (198cm) by comparason.
Also, if vegans are not drinking wine because the vine relied on insects, then they should only be eating purely synthetic food. Much of our food relies on insect pollination.
