Milk protein costs around 95 kg of CO2-equivalent emissions per kg of protein, which is apparently what was used in the production of this plastic [1]

[0] https://www.sciencedirect.com/science/article/pii/S002203022...

[1] https://ourworldindata.org/grapher/ghg-per-protein-poore

/scnr

I know - long lived plastics are bad. We need some kind of middle ground thats as cheap as the current plastics and doesn't last as long.

Well then it's not plastic is it? Plastic's defining characteristic is that it is not decomposable

That's 60 kg/person/year of plastic, which is a lot. Or about 4800 kg for a person living 70 years. Obviously, there is wide variation in this number across the human population.