So, I was debating this with someone and thought I’d calculate how much CO2 a horse emits compared to a car.
An average horse walks 4mph, has a lung capacity of 11 liters, and breathes 36 times per minute when walking.
That means the following:
36 * 11 = 396 liters expired per minute
396 * 60 / 4 = 5 940 liters per mile
Each of those liters contain an additional 4.5% CO2 when breathed out than when breathed in.
5 940 * 0.045 = 267.3 liters CO2 per mile
CO2 has a specific density of 1.98g/liter
267.3 * 1.98 = 529gr CO2 per mile (353g/km for us metric people)
According to the EPA, the average american car emits 411 gr CO2 per mile.
So a horse emits more CO2 than a car, is about 10x slower, can only carry two people, and will also emit CO2 at idle, as you can’t turn it off (well you can, but it’s been known to be permanent)
Now you may be wondering where I’m getting at. And no, I don’t want to ban horses. How would we film westerns if we did?
And no, I don’t think a horse pollutes more than a car. My point is CO2 emissions should be looked at as part of a wider picture that includes all components. Not like us Europeans currently do, as in France, for example, a horse would get the highest eco-tax, $10,000.