That's emissions. The problem with plastics is not emissions but their biodegradability (or lack thereof).

it's about rubber tires that shed a lot of micro plastic

Can't imagine this survives napkin scrutiny. A ten mile drive isn't using nearly as much hydrocarbon mass as 10k plastic bags. While most of the plastic hopefully winds up in a landfill, most of the gasoline is water and carbon dioxide by the end. It's tires versus bags. While tires shed, the mass lost in 10min is definitely quite a bit lower than 10k bags or the fraction that escapes the waste pipeline.

30mpg, 10 miles, means two pounds of gasoline, 910grams, knock off or add 100g for ethanol per your preference, a google says about 5grams per bag, so nearly 200 bags.

Nowhere close to 10k, but nontrivial. And, this gets reduced and sometimes outright negated if you reuse the bag. Doesn't mean we shouldn't evaluate if plastic shopping bags are the beat choice though.

I don't think replacing them with store bought doggy poo and cat litter bags is better. It's not a reduction and theres no reuse. If you find yourself discarding them outright, then find an alternative I guess.

I think your math is wrong. Most of modern cars do up to 150g of CO2 per 100km, there are other emissions too, but they are in way smaller numbers.

Thats comically wrong. Human Resting metabolism is on the order of 20grams of CO2/hr.

See: https://www.sciencedirect.com/science/article/pii/S036013232...

As for a kilo of gas per 10 miles- see https://en.m.wikipedia.org/wiki/Gasoline - says 0.71-0.77g/mL, standard conversion table says 3.785L per gallon. (https://www.engineeringtoolbox.com/volume-units-converter-d_...), and finally- since we're comparing burning gas for a car vs using it in plastic: the figure of merit is petroleum usage, not greenhouse gas emission. Technically, plastic and gasoline aren't going to be 1:1. But that's not napkin math anymore unless you're a petroleum engineer/chemist.

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.

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.

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.

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.

Also most of that weight is oxygen. The mass of carbon from the gasoline in an apples to apples comparison to plastic would be much lower.

It doesn't really make sense to be comparing plastic waste to CO2 emissions though. These aren't fungible.

10 miles in a 30pmg vehicle uses only 1/3 of a pound of gasoline, or roughly 150g. So, nowhere close to 10k or even 1k...

150g is only equal to about 1-5 of the reusable bags in CA grocery stores, depending on the store.

I can breathe CO2. I don't want plastic in my brain. These two things are not the same.

Cars don't only need gasoline to exist and work.

Don’t forget that a lot of carbon went in to making the road, the parking (deforestation or other land destruction for those should be considered too), the car itself, emissions from tyre wear, brake dust, some plastic for the single use medical devices necessitated by treatment of people struck by drivers, etc etc.

Though what is often forgotten is the insane amounts of plastic used in farming. Occlusion fabric for weeds, polytunnel skins, silage wrap, etc

I didn't forget, its just awfully hard to fit all that on a napkin.

>People dramatically over weight how bad plastic is for the environment.

I can only give a: what in the fuck are you talking about?? Modern medicine is literally finding microplastics in men's testes. "People" are dramatically underestimating how completely and utterly screwed the next dozen generations of humanity are with the plastic waste we've blanketed the earth in. Assuming humans survive that long.

Sure plastic aren't great for the environment when we're just dumping it out there without much care. Obviously reducing waste and reusing is what we should strive for on all fronts. Demonizing one thing results in overcompensation on the flip side and we know for a fact that that's not where we want to end up either. Remember when we tried to reduce paper use as much as possible because of deforestation? Or saturated fats?

> Remember when we tried to reduce paper use as much as possible because of deforestation?

No, I don’t. I do remember a push to recycle paper which was a net win for everyone.

> Or saturated fats?

Great counterpoint. Remind me of the benefits of having microplastics in your testes. Which part of that had scientists questioning historical data?

At least microplastics don't make you angry and violent that we can tell.

On the other hand, it's going to be around (relative to pre-emission levels) for a lot longer than the lead (paint gets chipped off and disposed of, we stopped using it in end-consumer products, etc)

There's some concern that microplastics in the brain could contribute to depression, anxiety, executive function disorders, autism, Alzheimer's etc.

As the amount of plastics in the brain increases who knows what it'll do to us.

I cycle to the supermarket and every bush I pass on the way is full of plastic.

How is that the fault of plastic wrappings and not the fault of people throwing trash onto the side of the road?

Where did I say that?

My bad, sorry. I also see it

> in first world countries

Most would consider The Netherlands to be a first world country, but I understand the term is anachronistic.

it's not about CO2 emissions, it's about plastic waste that eventually degrades to microplastics

> The impact of a 10 min car ride = 10,000+ plastic bags of emissions.

Emissions isn't the main problem with plastics.

But yes, we should also cut down on driving cars, or drive EVs, or take public transport.