The Supremacy of Skin

The Sepia Rainbow

I've been thinking about skin.  It started when my great granddaughter discovered the skin on my arm.  It was wrinkled and loose--and made her laugh.  

Old lady skin is not really all that funny, but it is odd.  As we get older, our skin may get stretched and, eventually, lose its elasticity.  So it wrinkles.  Rapid weight loss, inactivity, deconditioning are among the factors that can contribute to the amount of wrinkles and general looseness, and I seem to have a lot of those contributions.

Another thing that happens with old skin is that it gets more spots.  Age spots.  Liver spots.  The barnacles of age (including skin tags).  A little sun can emphasize those spots, darkening them, but also highlighting the spaces where no pigment is present.  All those little scars now show up in bright contrast to any skin that begins to show its melanin levels.

Thinking about skin and all these changes, I also had to wonder why my skin--white skin--is so privileged in our American Society.  Globally, white skin is pretty uncommon.  There are only small areas of the planet where white skin naturally occurs, and, while the population that has white skin is quite numerous today, white-skinned humans are--today--still a minority of human inhabitants of Earth.  

The image I posted above should be credited to Gail McCormick, the artist who made this cut-paper illustration from a map by Nina Jablonski and George Chaplin.  The map shows the distribution of skin color that comes from the production of melanin.  Melanin is produced in response to ultraviolet rays, blocking the harmful effects of those rays.  We might think that the obvious reason for so much melanin in the tropical areas of the planet has to do with the effects of UV rays on the skin (think skin cancer).  Jablonski's research, however, shows a deeper (than skin) reason for the need for more protection from UV:  the production of folate, which is needed for human reproduction.  Too much UV, not so much folate.  A reversal of sorts occurred later, as humans migrated out of Africa and arrived in the colder, less sunny regions of the planet.  Too little UV, too little Vitamin D, lots of rickets and other bone density issues.  

Interestingly, high levels of melanin also tracks with lactose intolerance.  At the same time populations were evolving to get more benefit from UV (skin cancers tend to show up later, after the reproductive years) they also evolved the capacity to consume milk from herd animals to increase the Vitamin D in their diet.  (See Marvin Harris, Good to Eat: Riddles of Food and Culture.)

I recently had a conversation with a dear friend about skin color and colorism.  He opined that eventually there would be enough intermarriage and mingling of populations that humans would all be a nice cafe-au-lait shade of brown and we could just be done with racism.  I agreed.  Populations meet, populations mingle, reproduction occurs.  The global majority is not white, so the chances are that, over time, there could be a leveling out of this skin color issue.  After all race and racism are both human constructs that contribute to violence and war, and we need less of both.  

Still, I couldn't help but think about what is happening on the planet right now.  We are seeing significant levels of migration away from the tropics.  The effects of global warming are real and intolerable.  As climate changes, more humans will seek to move to more tolerable spaces, farther north or south toward the poles, and right into those temperate bands where too much melanin becomes a health problem.  How will humans adjust?  Will we evolve toward less melanin?  That would really be an ugly outcome--the populations that are doing the most to destroy the habitat of melanin-rich populations occupy the habitat that is most inhospitable to melanin-rich skin.  

Jablonski is working to bring more public awareness and understanding of the issues that arise from skin color.  It's just skin, after all.  The surface.  Not the heart.  Not the mind.  Not the person.  We have so many, much bigger issues to deal with than how much melanin our ancestors gave us.  My great granddaughter's interest in the changes that age has brought to my skin makes me realize that now is the time to talk to her about the colors in my skin and where they come from.  Evolution might be a tough concept for a second grader, but human worth, regardless of skin color is an age-appropriate topic for discussion any time.  The sooner the better.