{"id":326822,"date":"2024-05-07T08:34:25","date_gmt":"2024-05-07T06:34:25","guid":{"rendered":"https:\/\/climatescience.press\/?p=326822"},"modified":"2024-05-07T08:34:27","modified_gmt":"2024-05-07T06:34:27","slug":"newly-discovered-90000-year-old-human-footprints-reveal-how-much-higher-sea-levels-used-to-be","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=326822","title":{"rendered":"Newly Discovered 90,000-Year-Old Human Footprints Reveal How Much Higher Sea Levels Used To Be"},"content":{"rendered":"\n
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From NoTricksZone<\/a><\/p>\n\n\n\n

By\u00a0Kenneth Richard<\/a><\/em><\/p>\n\n\n\n

Human footprints embedded into rock that used to be a sand beach at the limit of the seashore\u2019s \u201cswash flow\u201d and high tide lie 20 to 30 meters above the present sea level. The footprints are dated to ~90,000 years ago.<\/strong><\/p>\n\n\n\n

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<\/a><\/strong>).<\/p>\n\n\n\n

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Image Source:\u00a0Sommers et al., 2022<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

Evidence along the coasts of North Africa (Morocco) suggests sea levels were \u201c20 m above the present level\u201d about 95,000 years ago (MIS 5c).<\/p>\n\n\n\n

This is consistent with a new study<\/a><\/strong> that reports human footprints embedded and preserved in a rocky beach \u201c20 to 30 m above sea level\u201d can be dated to 90.3 \u00b17.6 thousand years ago.<\/p>\n\n\n\n

The water limit, or shoreline, very likely reached this elevation at that time, as the requisite conditions for \u201csalt-crusting,\u201d the preservation of footprints, involve a location at \u201cthe landward limits of the spring high tidal zone\u201d and at the \u201climits of swash flow\u201d.<\/p>\n\n\n\n

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Image Source:\u00a0Sedrati et al., 2024<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

Interestingly, this same Moroccan region\u2019s shoreline has, in recent decades, been stable to advancing seaward at a rate of +0.89 m per year (Amara Zenati et al., 2024<\/a><\/strong>). This is inconsistent with the viewpoint that sea level rise is poised to flood the Earth\u2019s coasts and shrink her shorelines.<\/p>\n\n\n\n

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Image Source:\u00a0Amara Zenati et al., 2024<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

And coastal expansion isn\u2019t 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 \u201cglobal coastline is prograding\u201d (Mao et al., 2021<\/a><\/strong>).<\/p>\n\n\n\n

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Image Source:\u00a0Mao et al., 2021<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n
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