The first problem is there's not enough lava. Per a few sources there have been ...

imesh · on March 28, 2021

There is certainly enough lava. The eruption that occurred in 2018 in my home town produced 1 billion cubic yards or 914402.757839 cubic kilometers.

https://volcanoes.usgs.gov/vsc/file_mngr/file-224/OVERVIEW_K...

I imaging the outgassing of the plastic would be pretty terrible but the volcanic gas is pretty damaging too. But yes, I imagine there are a hundred different reasons this wouldn't really work out.

minitoar · on March 28, 2021

I don’t think that math is right. 1 billion cubic yards is like less than 1 cubic km.

imesh · on March 28, 2021

You are correct. I messed that up bad and forgot how dimensions worked.

midasuni · on March 29, 2021

Yet even ignoring those two issues, you included 12 significant figures on a number that was likely 10% off in the first place.

Someone · on March 28, 2021

Nitpick: PVC sinks in water. That would make it over 1g/cm³.

Polypropylene and polyethylene do float, but don’t come near 0.05g/cm³. They’re closer to 0.9g/cm³ (https://www.plasticseurope.org/en/about-plastics/what-are-pl...). That’s close to icebergs.

ericbarrett · on March 28, 2021

You are right, seems I had a bad source—density is closer to 1.1-1.5 g/cm^3 than the 0.5 I used. So only 50 cubic km...

karamanolev · on March 28, 2021

In your post you mentioned 0.05, so that's not a factor of 3 off of 1.5, but instead a factor of 30...

ericbarrett · on March 29, 2021

A little more formally, with sources:

Density of plastic: https://omnexus.specialchem.com/polymer-properties/propertie... - Eyeballed at 1.2 g/cm^3

Plastic waste, lifetime: https://advances.sciencemag.org/content/3/7/e1700782 - 6.3 megatonnes (2017)

6.3 Mt / (1.2 g/cm^3) = 5250000 (5.25 million) m^3 = 0.00525 km^3

You were right! My math was way off. Thanks for noticing. This is a great demonstration of peer review :)