If plastic was made in 1907 how do they know it may take up to 1000 years to decompose?

Question

If plastic was made in 1907 how do they know it may take up to 1000 years to decompose?

In: Chemistry

Answer 1

Simple math.

If it takes 500 years to decompose 50% of a plastic sample, then it takes 1000 years to fully decompose.

If it takes 10 years to decompose 1% of a plastic sample, then it takes 1000 years to fully decompose.

Edit: As many of you have pointed out, yes, the relationship might not exactly be linear. I just gave an example to how we can find the time to decompose without actually waiting that long. It could be exponential, or any other model that can be solved by math. This was just an example so it would be easy for anyone to understand.