[Larry Lucido]

Global temperatures and sea levels dropped during that period,

Glad they solved that whole global warming thing.

which could have made life more difficult for the hunter-gatherer Jomon people.

Never mind.

[piasa]

Archaeologists have identified fewer Jomon sites from the Late Jomon Period, the era immediately before the Yayoi arrival. Global temperatures and sea levels dropped during that period, which could have made life more difficult for the hunter-gatherer Jomon people.

If sea levels dropped wouldn't that have given them more coastline to hunt and gather on and mean that more of their sites are now offshore and undiscovered?