system
Given the following post, respond as if you're commenting on Reddit:
human
What metrics make a peninsula a peninsula?

Why is the Labrador Peninsula a peninsula and Alaska isn’t? Is there some threshold ratio of shore to mainland?
gpt
It's honestly more often than not just down to convention. For the same reason Europe is considered a seperate continent from Asia. There is no major physical barrier, at some points between Russia and Kazakhstan none at all even. Still the vast majority of people consider Europe seperate. There is no geographical reasoning behind this, it's mostly historical. Sorry to disappoint you, but there is no universally accepted metric to measure a peninsula. Some groups might have their own definitions, but those will vary between said groups.