It's a bit misleading to claim that evidence 'now' pushes back human presence in the Americas to more than 15kya. I am surprised the Clovis First gatekeepers have yet recourse to such pretense given the far earlier dates many digs have revealed. AFAIK, no one reasonably disputes the 130kya date for evidence of human predation found in CA not long ago.
RE: Curating the Internet: Science and technology micro-summaries for September 1, 2019