Ice
<a href="https:&#x2F;&#x2F;www.scientificamerican.com&#x2F;article&#x2F;no-there-wasnt-an-advanced-civilization-12-000-years-ago&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.scientificamerican.com&#x2F;article&#x2F;no-there-wasnt-an...</a> should accompany this.<p>The whole younger Dryas advanced civilization think could have been avoided entirely and the point about ice melt rates would have been fine.