[dahart]

Human breath isn’t counted as fossil fuel emissions because the natural carbon cycle is a closed loop (all carbon we exhale came from our food and goes back to growing more food [1]), and also because humans don’t eat fossil fuels, of course. It’s the additional emissions from our fossil fuel burning machines that are causing climate change; we wouldn’t have CO2 driven climate change without the fossil fuel emissions, even if everyone was exercising. The fossil fuel emissions produce around 20x more CO2 than all humans breathing.

Taking the 6000km flight produces an additional ~1 ton of CO2 per passenger. A 777 emits around 10000kg per hour, or something like 70,000 kg of CO2 for one flight from Portugal to French Guiana. That doesn’t count the people breathing on the flight, and it doesn’t make any sense to compare a 7 hour flight to a few people taking several months to plan and execute an extreme paddle board trip. It’s the rate of additional CO2 emissions that matter, not the total number.

[1] https://www.mcgill.ca/oss/article/environment-quirky-science...

[throw7484877]

Why we regulate agricultural CO2 emissions, if the food we eat is "closed loop"?

I would say it takes a lot of fossil fuels to feed humans!!!

But I will keep this link, next time someone says I should eat bugs!

[dahart]

“Agricultural emissions” are coming from and regulated based on the machines involved, and animals, not really plants. We don’t require fossil fuels to feed humans, obviously, since humans didn’t use fossil fuels before a hundred or so years ago. We now have a system that happens to use unnecessary amounts of fossil fuels, and as always companies will externalize their impacts and and cut corners whenever possible. If we want to survive, it is looking more and more certain that we need to reduce fossil fuel based machine CO2 emissions.

BTW the cows vs bugs thing is because raising the scale of cattle we have is also completely unnecessary, and cows emit methane, which is way worse than CO2 and why cattle does count as ag emissions and is a concern.

Armchair climate science aside, it doesn’t actually matter where emissions are coming from, what matters is whether we can reduce them. We can’t really choose to stop breathing, and even if we did it cannot solve the problem we’ve created at all - human CO2 emissions is too small of a portion of total emissions. We can, however, choose to reduce fossil fuel and red meat consumption, and those things can make a real difference.