Wait, what? Sunscreens existed 41,000 years ago!

Wait, what? They had sunscreens 41,000 years ago? For all those who are arguing that wearing sunscreens is just another scam started by the cosmetic industry, it may be time to think again.

A new study from the University of Michigan suggests that ancient Homo sapiens may have benefitted from sunscreen about 41,000 years ago, long before SPF became a buzzword. The study published in Science Advances, suggests that our ancestors may have used natural sunscreen, tailored clothing, and caves to survive a dramatic spike in solar radiation, during the shifting of the magnetic North Pole over Europe about 41,000 years ago.

The study looked into a period known as the Laschamps excursion when Earth's magnetic field weakened to just 10% of its current strength, which led to cosmic rays and harmful UV radiation flooding the planet. The aurora was visible beyond the poles, and regions like Europe and North Africa were exposed to high levels of solar energy. And yet, our ancestors made it through. How? Researchers say part of the answer lies in behavior and adaptation.

Researchers noted that the North Pole drifted over Europe, weakening Earth's magnetic field, causing auroras over most of the globe and it also increased harmful UV radiation, coming from space. Around the same time, Homo sapiens appear to have started making tailored clothing and using ochre, a mineral that has sun-protective properties when applied to the skin, with greater frequency.

"In the study, we combined all of the regions where the magnetic field would not have been connected, allowing cosmic radiation, or any kind of energetic particles from the sun, to seep all the way into the ground. We found that many of those regions actually match pretty closely with early human activity from 41,000 years ago, specifically an increase in the use of caves and an increase in the use of prehistoric sunscreen," Agnit Mukhopadhyay, lead author and U-M research affiliate in climate and space sciences and engineering said in a statement.

Raven Garvey, U-M associate professor of anthropology also added Neanderthals and Homo sapiens coexisted in Europe, with Homo sapiens, who are often called anatomically modern humans, arriving roughly 56,000 years ago. By about 40,000 years ago, Neanderthals were no longer identified as a species in Europe.

"What some of the differences are between these species, between Neanderthals and anatomically modern humans, that might account for that disappearance has been a major anthropological question for decades," Garvey said.
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She added that clothing may have been a contributing factor. Archaeological discoveries have hinted that technological means of producing clothing that fitted the body are associated with anatomically modern humans, but not necessarily Neanderthals. They used tools like scrapers, awls, and needles, which hint at sewing, and these items are not found in Neanderthal sites.

Garvey stated that the tailored clothing has a twofold benefit: It was significantly warmer and the added warmth meant that people could travel farther from their hearths and shelters in search of food. The tailored clothing also provided another unintended benefit - protection from sun damage. She also noted how solar radiation at the time is linked to multiple detrimental effects including ocular pathologies and folate depletion (which can lead to birth defects and increased infant mortality). “so having protection against solar radiation would also have conferred a significant advantage to anyone who possessed it," Garvey said.

Homo sapiens may have also ramped up their use of ochre, a naturally occurring pigment composed of iron oxide, clay, and silica that has been used by many species of hominins for a very long time. People used it to paint objects, cave walls and even to decorate their bodies.

"There have been some experimental tests that show it has sunscreen-like properties. It's a pretty effective sunscreen, and there are also ethnographic populations that have used it primarily for that purpose. Its increased production and its association primarily with anatomically modern humans (during the Laschamps) is also suggestive of people's having used it for this purpose as well," Garvey added.

The researchers also emphasized that their findings aren't definitive. "I think it's important to note that these findings are correlational and (ours is a) meta analysis, if you will. But I think it is a fresh perspective on these data in light of the Laschamps excursion,” Garvey said.

Along with looking at how previous excursions might have affected humans long ago, Mukhopadhyay said the 3D model offers people a way to predict how excursions might affect us in the future.

"If such an event were to happen today, we would see a complete blackout in several different sectors. Our communication satellites would not work. Many of our telecommunication arrays, which are on the ground, would be severely affected by the smallest of space weather events, not to mention the human impacts which would also play a pretty massive role in our day-to-day lives,” he added.