CO2 from cycling?

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Hi All,

How much CO2 does a person generate while cycling or doing other heavy
exercise? How does this compare to the amount of CO2 generated while
sedentary?

I wonder if someone might make the case that cycling contributes to global
warming.

Gary Jacobson
Rosendale, NY

Quoted message said:

How much CO2 does a person generate while cycling or doing other heavy
exercise? How does this compare to the amount of CO2 generated while
sedentary?

My guestimate is about 12g/km when I am at my time-trial pace. This is
based on measurements taken during a VO2max test I took. At rest maybe
2g/min?

Looks reasonable. My estimate for touring rides is that I need an
additional intake of about 30 kcal/mile or just under 20 kcal/km.
Using metabolism of one of my favorite carbohydrates as an example:
C6H12O6 + 6 O2 => 6 CO2 + 6 H2O
implies that about 1.5 times as much CO2 is produced by weight as I
consume in extra carbohydrate. This works out to production of about 8
g/km over the sedentary base rate.

Now let's take an example of a small efficient car using 6 l/100km of
hydrocarbons (about 44 mpg in US terms). Using octane as an example:
C8H18 + 12.5 O2 => 8 CO2 + 9 H2O
So in this case about three times as much CO2 is produced compared to
the weight of gasoline burned. At 0.06 l/km the car uses about 48 g/km
and therefore emits about 150 g/km of CO2.

Gary Jacobson said:

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Hi All,

How much CO2 does a person generate while cycling or doing other heavy
exercise? How does this compare to the amount of CO2 generated while
sedentary?

I wonder if someone might make the case that cycling contributes to global
warming.

Sure. So does being alive. [So do flatulent cows]. And WD-40
lubricates, lighter tires make your bike accelerate more rapidly, and
ceramic bearings will decrease your rolling friction.

But all of these real effects are completely negligible in the grand
scheme of things - e.g. I'm sure that the CO2 generated in riding 10
miles is vastly smaller than the CO2 generated by a motor vehicle in 10
miles. Remember that the bicycle is *the* most energy-efficient way to
move a given mass a given distance.

(Not sure that the cows' methane emissions are negligible).

Mark

Gary Jacobson said:

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Hi All,

How much CO2 does a person generate while cycling or doing other heavy
exercise? How does this compare to the amount of CO2 generated while
sedentary?

I wonder if someone might make the case that cycling contributes to global
warming.

Only if all cyclists were overweight, wind sucking goons like me.

Ron

Gary Jacobson said:

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Hi All,

How much CO2 does a person generate while cycling or doing other heavy
exercise? How does this compare to the amount of CO2 generated while
sedentary?

I wonder if someone might make the case that cycling contributes to global
warming.

Gary Jacobson
Rosendale, NY

So living a sedentary is good? Don't let the environuts hear that.

😄

"peter" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

How much CO2 does a person generate while cycling or doing other heavy
exercise? How does this compare to the amount of CO2 generated while
sedentary?

My guestimate is about 12g/km when I am at my time-trial pace. This is
based on measurements taken during a VO2max test I took. At rest maybe
2g/min?

Looks reasonable. My estimate for touring rides is that I need an
additional intake of about 30 kcal/mile or just under 20 kcal/km.
Using metabolism of one of my favorite carbohydrates as an example:
C6H12O6 + 6 O2 => 6 CO2 + 6 H2O
implies that about 1.5 times as much CO2 is produced by weight as I
consume in extra carbohydrate. This works out to production of about 8
g/km over the sedentary base rate.

Now let's take an example of a small efficient car using 6 l/100km of
hydrocarbons (about 44 mpg in US terms). Using octane as an example:
C8H18 + 12.5 O2 => 8 CO2 + 9 H2O
So in this case about three times as much CO2 is produced compared to
the weight of gasoline burned. At 0.06 l/km the car uses about 48 g/km
and therefore emits about 150 g/km of CO2.

Thank you for this serious discourse. I asked the question about "Are
Cyclist Destroying the Earth?" after reading a NY Times piece with that
byline about Karl T. Ulrich,
a professor at U Pa. who espoused that cycling may do more harm than good.
Cyclists live longer and therefore consume more.

Gary Jacobson
Rosendale, NY

Gary Jacobson said:

I wonder if someone might make the case that cycling contributes to
global warming.

Perhaps, but only from the secondary effects. The CO2 generated by a car
while being driven comes mostly from petroleum hydrocarbons that were
originally captured millenia ago. The CO2 we generate while cycling comes
from the food we eat which (again, mostly) comes indirectly from
atmospheric carbon. Where the carbon comes from matters: we take it
indirectly from the atmosphere and put it back into the atmosphere, cars
that are fueled on petroleum take it from underground and put it back into
the atmosphere. The bottom line is that we're pretty much atmospheric
CO2-neutral while a conventionally fueled car pretty much isn't.

Robert Chung said:

Gary Jacobson said:

I wonder if someone might make the case that cycling contributes to
global warming.

Perhaps, but only from the secondary effects. The CO2 generated by a car
while being driven comes mostly from petroleum hydrocarbons that were
originally captured millenia ago. The CO2 we generate while cycling comes
from the food we eat which (again, mostly) comes indirectly from
atmospheric carbon. Where the carbon comes from matters: we take it
indirectly from the atmosphere and put it back into the atmosphere, cars
that are fueled on petroleum take it from underground and put it back into
the atmosphere. The bottom line is that we're pretty much atmospheric
CO2-neutral while a conventionally fueled car pretty much isn't.

This is true, but my interest lies in being able to judge what the
relative narrow differences between cars with slightly more or less
efficiency really mean. In the newspaper here it says such and such car
emits 160g/km and such and such car emits 150g/km. This tells people
which one emits more, but they have no understanding of what quantities
this represents.

Joseph

Quoted message said:

This is true, but my interest lies in being able to judge what the
relative narrow differences between cars with slightly more or less
efficiency really mean.

Yeah, but what it really means depends on what question you're really
trying to answer. For example, if you were interested in the atmospheric
CO2 effect, you could ameliorate the effect of a car by using a biofuel
like ethanol rather than pumping petroleum out of the ground. The CO2
output in terms of g/km would be the same (or close) but the net
contribution is very different.

Robert Chung said:

Quoted message said:

This is true, but my interest lies in being able to judge what the
relative narrow differences between cars with slightly more or less
efficiency really mean.

Yeah, but what it really means depends on what question you're really
trying to answer. For example, if you were interested in the atmospheric
CO2 effect, you could ameliorate the effect of a car by using a biofuel
like ethanol rather than pumping petroleum out of the ground. The CO2
output in terms of g/km would be the same (or close) but the net
contribution is very different.

I am writing a "letter to the editor" of our local newspaper. There is
a proposal in Norway now to change the taxes on cars to be based on CO2
emissions. That is fine, but it is the drastic scale they are going to
base things on, and the relative insignificance of cars in Norway to
the global issue that I am concerned with. Right now there are huge
taxes on cars based on weight, power, and displacemnet. A new Passat
starts at about 19,000 EUR in Germany, but the cheapest in Norway is
40,000 EUR. The only thing this acomplishes is having lots of people
drive around in older, less safe, and less efficient cars. The idea
behind the new CO2 proposal is to keep the overall price about the
same, but to make more efficient cars marginally cheaper, and less
efficient (and much less common already) cars much more expensive. This
is a non-solution if you ask me. And I think many people would agree if
they knew just how little a difference there is between the emissions
of "good" cars vs "bad" cars. If the people absolutely insist (they are
voters after all!) on keeping the total cost of car use sky-high, at
least drop the taxes on cars and raise it on fuel so we can at least do
our driving in modern safe cars.

Joseph

"Robert Chung" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Gary Jacobson said:

I wonder if someone might make the case that cycling contributes to
global warming.

Perhaps, but only from the secondary effects. The CO2 generated by a car
while being driven comes mostly from petroleum hydrocarbons that were
originally captured millenia ago. The CO2 we generate while cycling comes
from the food we eat which (again, mostly) comes indirectly from
atmospheric carbon. Where the carbon comes from matters: we take it
indirectly from the atmosphere and put it back into the atmosphere, cars
that are fueled on petroleum take it from underground and put it back into
the atmosphere. The bottom line is that we're pretty much atmospheric
CO2-neutral while a conventionally fueled car pretty much isn't.

I've been told thatt fertilizers used to grow the food we eat is largely
derived from petroleum..

Gary Jacobson
Rosendale, NY

Quoted message said:

The idea
behind the new CO2 proposal is to keep the overall price about the
same, but to make more efficient cars marginally cheaper, and less
efficient (and much less common already) cars much more expensive. This
is a non-solution if you ask me. And I think many people would agree if
they knew just how little a difference there is between the emissions
of "good" cars vs "bad" cars. If the people absolutely insist (they are
voters after all!) on keeping the total cost of car use sky-high, at
least drop the taxes on cars and raise it on fuel so we can at least do
our driving in modern safe cars.

<rant>Expensive cars and cheap fuel provides perverse incentive to
make people drive MORE. The capital cost is regarded as a sunk
investment, so you might as well use it as much as possible. Putting
all the tax on fuel achieves all the benefits of any of the
alternative schemes (purchase tax on vehicles, annual registration
tax, road-pricing, congestion charges) by driving consumers to make
low emissions attractive - they will buy smaller, more efficient cars,
use journey routes and times which minimise fuel consumption and
switch to lower cost methods for short and long journeys. The short
journey (0.5 to 5 mile) replacement is obvious to us cyclists, but by
eliminating car taxes and replacing them with fuel taxes, it will
become cheaper to hire a car at your vacation or business destination,
reached by rail (50 to 500 mile), than it is to drive there. All of
this is achieved using existing legislative, administrative and
judicial infrastructure, and without the appalling civil rights
infringement which is true reason why increasingly autocratic and
oppressive governments want to track our every movement with their spy
satellites. </rant>

Apart from that, I agree that comparing my CO2 from cycling with CO2
from fossil fuel powered vehicles is meaningless because I run on
bio-fuel

Kinky Cowboy*

*Batteries not included
May contain traces of nuts
Your milage may vary

Kinky Cowboy said:

Quoted message said:

The idea
behind the new CO2 proposal is to keep the overall price about the
same, but to make more efficient cars marginally cheaper, and less
efficient (and much less common already) cars much more expensive. This
is a non-solution if you ask me. And I think many people would agree if
they knew just how little a difference there is between the emissions
of "good" cars vs "bad" cars. If the people absolutely insist (they are
voters after all!) on keeping the total cost of car use sky-high, at
least drop the taxes on cars and raise it on fuel so we can at least do
our driving in modern safe cars.

<rant>Expensive cars and cheap fuel provides perverse incentive to
make people drive MORE. The capital cost is regarded as a sunk
investment, so you might as well use it as much as possible. Putting
all the tax on fuel achieves all the benefits of any of the
alternative schemes (purchase tax on vehicles, annual registration
tax, road-pricing, congestion charges) by driving consumers to make
low emissions attractive - they will buy smaller, more efficient cars,
use journey routes and times which minimise fuel consumption and
switch to lower cost methods for short and long journeys. The short
journey (0.5 to 5 mile) replacement is obvious to us cyclists, but by
eliminating car taxes and replacing them with fuel taxes, it will
become cheaper to hire a car at your vacation or business destination,
reached by rail (50 to 500 mile), than it is to drive there. All of
this is achieved using existing legislative, administrative and
judicial infrastructure, and without the appalling civil rights
infringement which is true reason why increasingly autocratic and
oppressive governments want to track our every movement with their spy
satellites. </rant>

Apart from that, I agree that comparing my CO2 from cycling with CO2
from fossil fuel powered vehicles is meaningless because I run on
bio-fuel

Kinky Cowboy*

In Norway which is essentially 100% rural, people drive as much as they
have to as there is no real practical option (mass transit can work in
densly populated areas, but in the sticks it is a different story).
Fuel is about 1.50 EUR per liter ($8 US/gallon). Extra taxes just take
people's money away, or deprive them of decent cars, as they already
are driving a minimum. A system where fuel taxes are raised
significantly, while car taxes are eliminated I believe wouldn't have a
significant impact on how much driving is done here. It would just
change what type of vehicles it is done in.

Joseph

Mark wrote:
(Not sure that the cows' methane emissions are negligible).

Quoted message said:

If memory serves, I read in a display at NOAA in Boulder that the number
two source of methane is cows, and the number one source is termites.

-Mark Schecter

In article <[email hidden]>,

Robert Chung said:

Gary Jacobson said:

I wonder if someone might make the case that cycling contributes to
global warming.

Perhaps, but only from the secondary effects. The CO2 generated by a car
while being driven comes mostly from petroleum hydrocarbons that were
originally captured millenia ago. The CO2 we generate while cycling comes
from the food we eat which (again, mostly) comes indirectly from
atmospheric carbon. Where the carbon comes from matters: we take it
indirectly from the atmosphere and put it back into the atmosphere, cars
that are fueled on petroleum take it from underground and put it back into
the atmosphere. The bottom line is that we're pretty much atmospheric
CO2-neutral while a conventionally fueled car pretty much isn't.

One theory proposes that most of methane and petroleum in
the crust have never been part of the biologic carbon
cycle.

--
Michael Press

Mark Schecter said:

Mark wrote:
(Not sure that the cows' methane emissions are negligible).

Quoted message said:

If memory serves, I read in a display at NOAA in Boulder that the number
two source of methane is cows, and the number one source is termites.

Not quite. http://en.wikipedia.org/wiki/Methane
skip down to the table under "Emissions of methane".
The dominant source of swamp gas is, well, swamps.
Termites are pretty small.
http://www.grida.no/climate/ipcc_tar/wg1/212.htm
http://www.grida.no/climate/ipcc_tar/wg1/016.htm#co2
http://www.grida.no/climate/ipcc_tar/wg1/017.htm
Methane is responsible for about 20% of the well-mixed-gas
radiative forcing on temperature change; CO2 is 60%.
Although many hydrocarbons, including methane, have a
stronger effect per kg than CO2, there is more CO2.

At Monday 24 July 2006 01:38 in rec.bicycles.tech Michael Press said:

...

One theory proposes that most of methane and petroleum in
the crust have never been part of the biologic carbon
cycle.

Very few geologists accept that hypothesis.

<http://en.wikipedia.org/wiki/Abiogenic_petroleum_origin>

RRS

Gary Jacobson said:

I've been told thatt fertilizers used to grow the food we eat is largely
derived from petroleum..

Depends on the fertilizer nutrient. Nitrogen chemical fertilizers are
made almost entirely from Natural Gas, not petroleum. P & K are not,
though various fossil fuels are used in their manufacture.

Matt (IAAAE) [I Am An Agricultural Economist]

Matt said:

Gary Jacobson said:

I've been told thatt fertilizers used to grow the food we eat is largely
derived from petroleum..

Depends on the fertilizer nutrient. Nitrogen chemical fertilizers are
made almost entirely from Natural Gas, not petroleum. P & K are not,
though various fossil fuels are used in their manufacture.

Matt (IAAAE) [I Am An Agricultural Economist]

Dear Matt,

I have been trying to sell Crab Key for half a century now since I dug
my way out of that pile of--

Anyway, I resent meddlers like you trying to lower the value of my real
estate.

Several blind gentlemen of mixed Chinese and African persuasion will
soon be calling on you to explain why agricultural economists should
recommend no fertilizer except guano, guano, guano!

I'd pedal over myself and threaten you in person, but I still haven't
got the hang of manipulating these odd new brifters.

Ominously,

Julius No, M.D., IAAMSWSG (I Am A Mad Scientist Who Sells Guano)