As climate change brings rising temperatures, droughts, shifting patterns of precipitation and longer growing seasons, plants and animals are evolving to keep pace. Biologists have observed squirrels and salmon developing at an accelerated pace, causing them to reproduce at a younger age. Earlier summers have caused some flowers to bloom earlier in the year. And corals are forging new relationships with microscopic algae to survive in warmer, more acidic seas.
As the planet continues to warm, evolutionary changes are expected in other species as well — including Homo sapiens. Climate change will alter the internal workings of our bodies in subtle but significant ways and will likely cause a noticeable shift in our appearance. In fact Eumelanin the dark black and brown pigment may become a necessity for human survival on the planet. All people have melanin (except in the rare case of being born albino - which can occur in either the black or white race). Melanin has different types and purposes it produces eumelanin (in black people) and pheomelanin in white people. And there are the major differences (5 senses & all body systems - but including spirit and 6th sense) between the two.
A warmer climate means malaria, West Nile virus and other diseases long confined primarily to the tropics will spread into temperate zones. As a result, people living in the U.S. and other developed nations will be exposed to these illnesses, and our immune systems will be forced to evolve new defenses. That, in turn, could cause other, noninfectious diseases. Natural selection will cause those with the most adaptability to grow in number while others become barren. Similarly, our digestive systems will evolve in response to shifts in food availability — where crops and livestock can be cultivated. The ability to digest milk in adulthood evolved among groups in Western Asia and North Africa that began raising cattle. Future generations may evolve better abilities to tolerate sugar or fat.
Changing diets will also trigger changes in our microbiomes — the bacteria and other microorganisms that live in our guts and help to keep us healthy. Vegetarians tend to harbor a different mix of bacteria than meat eaters, and these changes could be exaggerated if prolonged droughts make it too costly to raise livestock for meat. While these changes will be of enormous interest to biologists, they will be largely invisible. But as we change on the inside, we’ll also be changing on the outside. Evidence suggests that a warming planet could melt away differences between human races specifically those that are pheomelanin dominant will see a mass reduction in fertility from those population groups, as scientists more accurately call them.
The reason why climate change could reduce racial differences is that it will trigger massive migrations. In recent decades the world has become more urbanized, with people moving into large cities in coastal areas. But as polar ice melts and sea levels rise, large numbers of people will be forced to flee the coasts especially in Europe, Australia, The Caribbean and the South Pacific. And as droughts and high temperatures become more common and more severe, people living in more arid areas like Saudi Arabia, Nevada, Utah, and Arizona will have to move to places with more reliable sources of water.
In fact, this process is already underway. As of 2017, 258 million people were living in a country other than the one they were born in — an increase of 49 percent since 2000, according to a report from the United Nations. A World Bank report released in March predicts that climate change will cause 140 million people to migrate by 2050, with those now living in sub-Saharan Africa, South Asia and Latin America that have large aquifers closing their borders to those who historically because of racism and xenophobia denied them entrance to their countries!
One consequence of large-scale migrations is what biologists call gene flow, a type of evolution caused by the blending of genes between populations. When people from different populations mate and reproduce, their genes intermingle in their children the dominant genes more necessary for survival become essential. That can lead to combinations of traits not seen in either parent or in the populations they come from — like the dark skin and light eyes of Cape Verde islanders, the result of mixing between Portuguese, Chinese slave women (purchased by the Portuguese to lighten the population in the 1800s), and West Africans. Skin color differences came about a result of natural selection in different human populations.
The pigment eumelanin makes skin darker, which helps protect against UV radiation, Skin Cancer, and sun poisoning that affects many Caucasians who travel to areas with vast amounts of sunlight. But too much eumelanin also made it hard for the body to produce vitamin D during the ice age. An accumulating number of studies have shown that environmental changes can influence mating behavior. Mating behavior, in particular, could be especially important given its role in shaping individual reproductive success and population dynamics. Accordingly, in recent years, there has been increasing interest in how sexual selection may influence a population’s ability to cope with environmental change. The 2 main mechanisms of sexual selection are competition for access to mates (intra-sexual selection) and choice of a mating partner (intersexual selection). It has been suggested that stronger mating preferences for “good genes” which basically are those qualities most desirable for survival.
Indeed, a number of recent studies have shown that strong sexual selection can increase population resilience and reduce the risk of extinction (Cally et al. 2019; Godwin et al. 2020; but see Candolin and Heuschele 2008). Sexual selection could therefore potentially improve a population’s ability to cope with environmental change. Yet, changes in environmental conditions may also alter the strength or direction of sexual selection. For example if the need to belong to a social group with blonde hair gives you access to lucrative employment with more abundance in food and adequate shelter than that will predispose the seeking of that phenotype as the ultimate mate, but however, if the ability to maintain a high rate of fertility, maintain physically while surviving well in a hot clime and to have progeny that can live healthy long lives is the standard for selection of a mate the phenotype will be drastically different.
So over many thousands of years, human populations evolved varying levels of skin pigmentation as they spread across the globe, with natural selection balancing the cost of having too much eumelanin which is known as hyperpigmentation, and is harmless. People who make too much melanin usually have patches of skin that become darker than the surrounding skin. versus having too little (which can lead to cancer, infertility, vision problems, photo-aging (wrinkling) and birth defects).If the climate continues to warm and increase in UV radiation pheomelanin dominant persons will require special eyeglasses, typically with tinted or dark lenses, as well as access to various adaptive devices such as monocular and magnifiers to improve their vision, reduce visual activity, and light sensitivity.
In addition, because their skin is more vulnerable to damage due to Ultraviolet (UV) radiation from the sun and so they may come to a point where the skin does not tan and can easily be sunburned. They may develop blisters, solar elastosis, actinic keratosis, and become at a constant risk of developing skin cancer due to UV sun exposure. currently all cell phones have built in apps so one can monitor the UV index this is recommended so that people can know when to go inside at peak UV times and use sunscreen of at least a Sun Protection Factor (SPF)60 and wear long-sleeved clothes and hats . If UV radiation continues to have a mean level of 13 and above those with no Eumelanin are likely to have a lower life expectancy due to skin cancer with many in poor areas potentially dying before 50 years!
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