[hedgehog]

I think the units there are off, a Camry hybrid is about 100g direct CO2 per km. One widely repeated calculation has total direct + indirect emissions for a grocery bag at 200g. So 1km driven vs 1 bag is a similar magnitude of emissions.

[privatelypublic]

Please be careful of such "metrics/statistics." Their very nature means they're politically and financially incentivized lean towards a higher or lower number than "the other guy." And, of course, a big number is scarier in a vacuum. What if a paper bag is 250g of emissions?

The poster child for me for this is low-GWP refrigerants. Sounds good, right? Well, think about how CO2 captured filtered and compressed compares. I'll leave everybody to argue with their-self on this. Does co2 vs r-whatever use more energy? Less? Does it somehow justify the emissions and pollution of manufacture?

My conclusion is... I don't know.

[hedgehog]

We have enough data to estimate the reasonable range of possibilities and exclude the upthread assertion that a ten minute car ride is similar emissions to 10k plastic bags. A degree of uncertainty need not make us helpless in the face of loud ignorance, that's how we end up giving equal weight in the media to common consensus of professionals in whatever field and political operatives with fringe beliefs but no evidence.

[privatelypublic]

Sorry, I screwed up and misread what you wrote- primarily, a simple "we can do way better than 30mpg." And theres not a lot in the way of wiggle room to debate with any integrity the amount of CO2 burning a set quantity of gas produces. A couple percentage points for NOx and friends and thats it.

I am confused why everybody mentions emissions though. In a discussion on paper/plastic/reusable bags, in a response to a call for napkin math for a claim of "10,000 bags from the fuel needed to get to the store" (essentially the argument made)- CO2 isn't relevant: just the mass of the gas used to get to the store.

I'm not pleased with how this turned out. to be told I'm wrong? That's fine, its the internet. I'm disappointed and alarmed with how badly wrong the suggested corrections are... it's deeply frustrating for me as well.