Stone Age SPF: How An Ancient Mineral May Have Helped Humans Survive The Sun
Long before beach bags and bottles of SPF, early humans may have reached for something far more basic to protect themselves from the sun: dirt. That's according to experts who have a new theory about how our ancestors may have survived a serious spike in ultraviolet radiation thousands of years before sunblock (as we know it today) was invented.
Let's rewind the tape to about 41,000 years ago when Earth's magnetic field had a bit of a crisis. Scientists at the University of Michigan, in a new study published in Science Advances, reconstructed what happened during the infamous Laschamps geomagnetic excursion, a two-millennia-long episode where Earth's magnetic field plummeted to just 10% of its usual strength and the poles began to, for lack of a better word, wander.
(MORE: Were Earth's First Oceans Green?)
During the Laschamps, Earth's magnetic field, which shields us from solar radiation, became multipolar, with zones popping up unpredictably. Auroras were no longer Arctic exclusives; they moved into much lower latitudes. The weakened magnetic field meant more ultraviolet radiation was leaking through the atmosphere, and some of our ancestors quickly adapted.
Both Neanderthals and anatomically modern humans were living across Europe when this chaos kicked off. Evidence suggests both groups had richly pigmented skin, hair, and eyes—but it turns out, even that wasn't enough.
Groups of anatomically modern humans started using ochre, a yellow mineral loaded with iron oxide, in greater quantities, possibly as a prehistoric sunscreen. They also began crafting tailored clothing that may have acted as additional protection. These weren't just random upgrades, they were survival tools in their new radiation-filled environment.
(MORE: New Telescope Captures Blasts From The Sun)
Neanderthals, by contrast, mostly stuck to draped cloaks and simpler tech, with no evidence that they used anything for sun protection. While their extinction was likely due to a blend of factors, it's possible this played a part. You could say pants and sunscreen might've saved humanity.
Now, here's the kicker: Earth's magnetic field has been weakening again. Not to Laschamps levels, but it's declined by about 1% every 20 years for the last 180 years. And the poles? They're not sitting still either.
(MORE: Scientists Link Centuries-Old Mystery To Weather Patterns)
If a modern-day Laschamps like event occurred, it wouldn't just fry your skin—it would wreak havoc on satellites, communication networks, GPS, and international flights.
So, next time you're gazing up at the aurora or slathering on sunscreen, just remember: we've been here before. Only this time, our survival might depend less on ochre.
Weather.com lead editor Jenn Jordan explores how weather and climate weave through our daily lives, shape our routines and leave lasting impacts on our communities.
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