Newly Discovered 90,000-Year-Old Human Footprints Reveal How Much Higher Sea Levels Used To Be

Human footprints embedded into rock that used to be a sand beach at the limit of the seashoreโ€™s โ€œswash flowโ€ and high tide lie 20 to 30 meters above the present sea level. The footprints are dated to ~90,000 years ago.

From NoTricksZone

Byย Kenneth Richard

Human footprints embedded into rock that used to be a sand beach at the limit of the seashoreโ€™s โ€œswash flowโ€ and high tide lie 20 to 30 meters above the present sea level. The footprints are dated to ~90,000 years ago.

It is estimated that sea levels were globally about 6 to 9 meters higher than today during the last interglacial (~130,000 to 115,000 years ago), when CO2 supposedly peaked at 275 ppm (Sommers et al., 2022).

Image Source:ย Sommers et al., 2022

Evidence along the coasts of North Africa (Morocco) suggests sea levels were โ€œ20 m above the present levelโ€ about 95,000 years ago (MIS 5c).

This is consistent with a new study that reports human footprints embedded and preserved in a rocky beach โ€œ20 to 30 m above sea levelโ€ can be dated to 90.3 ยฑ7.6 thousand years ago.

The water limit, or shoreline, very likely reached this elevation at that time, as the requisite conditions for โ€œsalt-crusting,โ€ the preservation of footprints, involve a location at โ€œthe landward limits of the spring high tidal zoneโ€ and at the โ€œlimits of swash flowโ€.

Image Source:ย Sedrati et al., 2024

Interestingly, this same Moroccan regionโ€™s shoreline has, in recent decades, been stable to advancing seaward at a rate of +0.89 m per year (Amara Zenati et al., 2024). This is inconsistent with the viewpoint that sea level rise is poised to flood the Earthโ€™s coasts and shrink her shorelines.

Image Source:ย Amara Zenati et al., 2024

And coastal expansion isnโ€™t just a local phenomenon. Globally, shorelines have been advancing seaward at a rate of +0.26 m per year since the 1980s, as, despite sea level rise, the โ€œglobal coastline is progradingโ€ (Mao et al., 2021).

Image Source:ย Mao et al., 2021