The 2023 follow-up study — using conifer pollen and quartz grain luminescence dating to provide independent confirmation of the Ruppia seed dates — substantially strengthened the case for the 21,000 to 23,000-year age range.

But it is worth being precise about what changed and what did not.

What changed: the primary methodological objection to the 2021 findings — that the Ruppia seed dates might be artificially old due to the aquatic reservoir effect — was addressed by independent dating approaches not subject to that effect.

The concordance of multiple dating methods using different materials and different physical principles is the standard by which geochronological claims are evaluated, and the 2023 study brought White Sands significantly closer to meeting that standard.

What did not change: the interpretation of the footprints as human remains well-established.

What the 2023 study addressed was specifically the age question, not the identification question.