Why do these two maps not match ? I don’t get it. Annual sunshine and skin colour. It doesn’t make sense to me that people of North Africa have a lighter skin tone than sub Saharan populations.

In the case of North Africa and the Arabian Peninsula, it is important to keep in mind that the environment collapsed after the Early Holocene, beginning around 8,000 years ago. The Pleistocene inhabitants of these regions were bottlenecked down to small pockets that are virtually missing from the human genome today. There is a hypothetical prehistoric population called Basal Eurasians, who are thought to have descended from the first successful modern human expansion out of Africa and are now extinct. So what you’re seeing on this map is partially a factor of climate change - places that were once inhabitable and supported large populations but have now turned to desert. The contemporary populations moved in much later and are not necessary representative of the earlier inhabitants.

The second map represents modern day, for example you can see that the southeast US’a average skin tone is a lot darker since there are so many African Americans in that region of the country. This map take into account history and isn’t completely representing the native populations of each continent. Also in North Africa there are a lot of people who are quite light skin who are native to the region, such as the berbers.

Skin tone is not a result of hours of sunlight, but by the sun’s intensity. That intensity is determined by how much atmosphere the sun needs to penetrate.

The only regions on earth that receive the full intensity of the sun are the tropics (between approximately 23° north and 23° south of the equator.) The sun is directly above 23° N (the Tropic of Cancer) on the summer solstice and 23° S (the Tropic of Capricorn) on the winter solstice.

The curvature of the atmosphere means that more solar radiation is blocked the further north or south you are in the earth. Therefore, humans who migrated further north or south of the equator no longer needed as much melanin in their bodies while those who stayed in the tropics maintained their need for melanin and therefore darker skin.

So knowing this, we can see that skin color correlates far more directly with latitude than with sunlight hours. Cloud cover has little effect on the amount of atmosphere blocking the sun which is why it’s possible to be sunburned on a cloudy day

I hope this is a sufficient explanation. Had to type it on the fly

Because anthropology is not as simple as u think. Migration is one main factor I can think of but there are thousands more.

You can count the migration. People always move on.

As an Algerian I can tell those maps are a bit misleading since the vast majority of my people live in the coast which got mideteranian climate or right below the coast which has a step like climate. In these climates unlike the subtropical and tropical climates of SubsharanAfrica, it is sharply cold at night and winter with lots of clouds. Hence why Berbers or Amazighs wear a lot of thick covering cloths.

I would regard some aspect of human geography in understanding this. Mean the people who occupy this region likely have gene similarities to other people in other regions. When people move they bring genes with them and they these characteristics will last through generations.

Really interesting article from Penn: The varying skin colors of Africa: light, dark, and all in between ,

r/history maybe?

Somebody doesn't understand history exists

UV light is much stronger around the equator, this has the biological effect of darkening the skin. A lot of sun hours in say northern Siberia does not offer the same UV light year round hence wont produce the same biological result.

Also relevant is elevation, higher places have stronger UV. I believe there is a mountainous area in Peru or thereabouts that had a UV index of 40+ at some point. Quite different from 1-15 index we see more generally.

A lot of this is because you're using the 21st century. If you take native peoples before Columbus, you end up with something much closer. Also, even then migrating people only changed color slowly. Here's a map of human history and just before Columbus is pretty close to the sun map.

https://commons.wikimedia.org/wiki/File:Human_Skin_Colour_Distribution_26,000_BC_-_1500_AD.gif

Deserts get more sunlight, but they are very sparsely populated. They amount to not much more than seas of sand that divide the more densely populated temperate and tropical regions. Also, as others have pointed out, it's the intensity of the sunlight in the tropics that favors people with darker skin (and vice versa), not really the annual sunshine hours.

Peoples of the past didn't stay in the sun at all hours of the day, they had shelters. They would only go into the sun for as long as it took to get the sustenance and resources they needed. This means people that lived in drier regions only spent as much time under the sun as needed and people that lived in rainy places would definitely prefer to go out only when it was sunny, hiding from rain and storms in their shelters. This means the real difference isn't the amount of time spent under the sun, but how intense that sunlight was.

Don’t forget migration of peoples makes a huge difference too. North Africa is much more accessible than sub Sahara Africa. North Africa has been invaded, settled and colonized by many lighter skinned peoples. Like the Phoenicians, Greeks, Romans, Arabs, Spanish, Italians, French and the British just to name a few.

People move around.

What study did the first map come from? I could see it being a map, less of sunshine hitting earth more of sunshine hitting ground as the highest intensity areas for each latitude seem to correlate with deserts or otherwise treeless areas to me.

You’re mistaking geography for anthropology... There are countless biological and evolutionary factors, as well as historical context (migration, movement, war) that could affect something like that.

At least a portion of this can be explained by a little diddy I like yo call "All of Human History"

If you think exposing pregnant woman to the sun will turn the baby to black then its not the maps its just you

Or by this you mean everyone should be on his natural place depending on his skin( just kidding this one is my own idea, imagine)

The UV radiation in the Subtropics is much stronger than north of it

It’s not about how long people are exposed, it’s about how strong that radiation is

UV index is stronger around the equator regardless of sunlight hours.

North Africans are off Caucasoid ancestry. Sub Saharan Africans are Negroid.

people have legs, they move.

They don't match because the skin color map is pretty wrong

About 1.5million slaves were taken from Europe to N. Africa. That might help explain the 'dilution'.

Six hundred fucking hour variance😒 gtfoh

North Africans are arabs, they are not native Africans, that's why.

Shadey

One word: Colonialism

Your interpolation sucks

I highly doubt that there are more sun hours in northern Sweden than in the south. Doesn't make sense.

Oh boy, I fear this is another (American?) Culture labeling (woke?) Question, even worse: basing the skin tone.... So it depends on what time of the year are we talking about, is it before or after summer? (Orange people don't count for this very scientific survey)

Their long clothes are made to protect themselves from the sun

It's a racist map.

What does sunlight have to do with skin pigment? Do you really think black people would turn white if they spent less time in the sun?!?!

Sunshine has a lot more to do with geography. Deserts get alot of sun because there are never any clouds to block sunlight while rainforests don't get as much sun because there are way more clouds.

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It also has to do with migratory people. As you muve towards the Mediterranean, civilizations were able to travel. This would definitely affect the populations genomes.

Migration. Skin color comes from before civilizations formed. Once people advanced and formed large functional societies they moved into areas that their hunter gatherer ancestors wouldn't have settled in.

Not sure how accurately I’m relaying the point but I read that the evolution of skin tone had more to do with diet than sunshine (but it’s indirectly related). There are advantages to having less pigment if your diet is based more on meat for protein which is more reflective of northern latitudes where there is less sunlight. And as people have pointed out, people migrate so it’s not surprising that the maps don’t match up completely.

Because skin colour isn't solely driven by ambient temperatures, maybe? I mean, there are hundreds of variables at play here. One example might be percentage of lives spent outdoors.. The wealthier a country gets, the less time the population tends to spend outside. But as I say, that's just one. There are loads of factors.

Simple answer: big desert hard to impossible to cross for generations

You got some pretty tetchy responses! :D

Equator has more direct sunlight throughout the year

I'm pretty sure it all depends on migrations of genotypes. Not so much annual sunshine anymore.

this map is modern day but even when it comes to indigenous peoples remember humans are not native to NA, they likely came through alaska from russia. Also most modern day indigenous peoples have mixed haritage with europeans which will make their skin lighter through generations.

Why is there a small green tip in southwest Portugal? Odd, Ik it makes less sun there than southeast Portugal but it's still above Yellow, and definitely more than in porto, witch is I'm yellow

Anyways population movement is one good awnser

North Africa has been interconnected with Europe since the dawn of history, spreading genetics and culture. The Mediterranean was a melting pot basically forever because of this.

Sunshine level doesn’t move much but people do. Darker skin also helps with heat dissipation in addition to preventing burning, so it makes sense for sub-saharan Africa where it’s hot and humid AF.

I thought there was a sizeable amount of white skinned people in south Africa? Around Cape town. Can someone fact check me

Genetics

You have to factor in that a lot of migration has happened.

Genetics

In recent times (several thousand years) humans have become more capable of mitigating the selective pressure of sun - by using clothes in areas with intense sun and through diet in areas with weak sun. The latter is harder, that's why you don't see very dark people in native populations of high latitude. Only in the modern era (food abundance and direct supplements) can very dark skin resist the selective pressure of rickets close to the poles.

So what you see is human migrations since human material culture made them capable of mitigating the multi generational effect of sun intensity.

I would probably summarise my response as:

Populations move but are determined by geography.

TSI moves but is not bounded by geography.

You are looking at the discrepancy

you're also confusing sunlight vs days without cloud cover. I can guarantee the sun beating down on the equator is a hell of a lot more oppressive than sunlight at higher latitudes over longer periods of the year.

“Doesn’t match,” bro have you heard of this thing it’s called transportation. Roads and feet, then wheels. Lately, wings. Even “native” peoples have been migrating for millennia.

So we in the Maghreb have “East-Asian” skin color!!

There are lots of factors, the simple is, this doesn't surprise me. Any person on the planet, naked and forced into the sun will be dead in 3 days, no matter the color of their skin. The sun will skin them alive.

I think skin color evolved through nature selection and sexual mating selection. An environmental factor doesn’t force a change but can benefit certain traits.

A certain environmental condition like a bright sun may make it beneficial to be resistant to it, but as long as you can make a bay before dying you will pass on some of your genetics.

There are lots of places that dont make sense.

Does North Africa include Sudan, South Sudan or Eritrea ?

Off the top of my head .

Andaman Islands vs almost everybody around them

Australia vs New Guinea vs Samoa vs Tasmania vs New Zealand vs all nearby other Pacific Islands (only applies for the Natives of these places)

Philippines vs New Guinea

Tunisia vs Libya vs Malta vs Silicy vs Crete

Siberia vs Alaska vs Greenland vs (Northern Norway, Northern Sweden, Northern Finland with the Sami People)

Many errors in this map when it comes to Native Populations.

When it comes to the second map whats consider East Asian People ; The Ainu people (the Natives of Japan) mess that whole skin color thing up.

The natives of New Guinea, & Australia should be darker than most of Africa

A large population of India are the same complexion as Africans and some times darker the difference is facial features but skin color is almost the same.

Sentinal Island along with the Andaman Islands most of less should be the darkest spot on the map (they arent shown) 98 % of all Africans, Native Australians, & New Guineas have lighter skin color than them.

The original inhabitants of North Africa were dark-skinned Berbers and brown-skinned ancient Egyptians. After the Phoenicians and the Romans, it's been mostly Arabs for the last 1500 years.

Evolution should adapt skin color to sunlight over the next hundred thousand years or so.

North Africa closer to Europe maybe they mixed

I'm guessing, bit there has been a lot of interaction been N African population and arabic and Mediterranean populations, for at least a few millennia. That might explain that lighter brown skin tone common in Africa.

Because they’re are invading bastardized people.

Migration and interracial breeding probably explains a lot of it.