FUTURESTATES | White | Episode | ITVS

We are in an age where man has changed the surface temperature of the globe. It was surface temperature that changed the Oceans and caused the demise of the dinosaur, now with ozone depletion and high UV radiation we are faced with a dramatic change in our ecosystem again. Some of us will be better off in this hotter warmer world .Melanin helps reduce the absorption of UV wavelengths into the skin (Chaplin, Jablonski, 59). The more melanin in the skin, the greater the protection against harmful UV rays, and the amount of melanin in the skin correlates with the skin’s color (more melanin means darker skin).Because Africa was a very warm climate that received lots of sunlight the first humans had dark skin in order to protect them from detrimental effects of UV rays. However, like humans today, the first modern humans did not stay in one place and various groups moved to various regions of the world. Moving to new regions meant coping and adapting to a new environment.
Geographical isolation in the past has caused a variation in skin color; natural selection selected specific skin pigments depending on environmental factors. Early Africans who moved to Europe were introduced to a place that had less sunlight than their former place of residence. Overtime, light skin (skin with lower levels of melanin) was selected for since there were not as many UV rays that the skin needed protection from. But, what was wrong with having dark skin in Europe? How is extra melanin a disadvantage in this case? One thing to remember is that even though the sun can provide UV rays, sunlight is also a great source of natural vitamin D (Jablonski; Kirchweger). Vitamin D helps bones absorb calcium and is particularly essential for developing embryos in pregnant women. The adaptation for lighter skin was important because the skin needed to absorb as much sunlight as it could in order to receive optimal amounts of vitamin D (Kirchweger). However, too much vitamin D can be fatal. So as high amounts of melanin protected the skin from excessive UV rays in Africa, they also protected it from excessive vitamin D (Kirchweger).
Lighter skinned humans had an advantage with obtaining an optimal amount of vitamin D because their skin drank in the sunlight but he cost was loss of bone density and the other protective advantages of melanin. Darker skinned humans had an advantage over another nutrient: folic acid (folate). Folate is essential for proper DNA synthesis. The lack of substancial folate can lead to disorders in developing embryos and infertility in males (Chaplin, Jablonski 61). UV rays contribute to folate photolysis (the breakdown of folate), therefore a high melanin content in the skin can eliminate or cut down on such damage. Overall, both light skin and dark skin have their advantages when it comes to living in certain environments. Yet, how does skin color affect the future? When it comes to non-melanated populations without Eumelanin protection it is very clear. Climate change has likely been contributing to a steady decline in the European, Australian, Chinese, South American and U.S. birth rates, researchers said, predicting as many as 100,000-250,000 fewer babies born in the USA each year by the end of the century.
Data shows the number of babies born drops in the eight to 10 months after a spate of days on which the average temperature exceeds 80°F (26.6 °C),the more hot days in the year the lower the birth rates, according to research by the National Bureau of Economic Research, a non-partisan group based in Cambridge, Massachusetts. Researchers declined to state a definitive reason. Many may have fewer sexual relations during warmer weather, or more likely such weather affects reproductive health, they said. For white men, exposure to extreme heat can negatively affect semen quality and testosterone, and in women it could have an impact on menstruation, ovulation and implantation of fertilized eggs. The data showed that on average between 1931 through 2010, each hot day resulted in 1,165 fewer baby births in predominantly white populations across the United States some nine months later. The trend could result in some 100,000 fewer babies born to caucasians per year in the United States by 2050, according to the study. "We still don't know exactly how these temperature shocks are going to impact developing countries," said Alan Barreca, a co-author and professor of economics at Tulane University in New Orleans, Louisiana.The U.S. birthrate in certain populations has largely been on the decline over several decades, although the number of births increased slightly in 2014 in Black and Hispanic populations, according to the Centers for Disease Control and Prevention. A new study from the Norwegian University of Science and Technology shows that increased UV radiation can have an effect on human fertility over generations.
Gine Roll Skjærvø at the Norwegian University of Science and Technology's (NTNU) Department of Biology has studied church records from 1750-1900 and looked at life history variables: Skjærvø and her colleagues found that children born in years with lots of solar activity had a higher probability of dying compared to children who were born in years with less solar activity.An 11-year cycleOn average, the lifespan of caucasian children born in years that had a great deal of solar activity was 5.2 years shorter than other children. The largest difference was in the probability of dying during the first two years of life. Children who were Caucasian and born in years with lots of sunshine and who survived were also more likely to have fewer children, who in turn gave birth to fewer children than others. This finding shows that increased UV radiation during years of high solar activity had an effect across generations.