Climate change. It’s a phrase we hear often in today’s society and rightly so.Climate change affects the whole environment – yes, I am talking on a really large scale. When we hear the word climate change most people just think about ice-bergs falling and increasing water levels. But that’s not it. Because of climate change, organisms around the globe are having to modify their structure and metabolisms.
In normal situations, whenever a species can’t adapt to a certain environment they move to an area that is suitable for their conditions. For instance if an environment is too hot for them they move to a colder environment. It’s pretty straightforward. However, the question is will animals even have time to find a new environment due to the rapid effects of climate change? Most researchers believe that climate change is happening too fast for animals to keep up. Recent reports have shown that apparent warm-blooded animals are going through evolution so they can adapt to warmer environments, by developing larger beaks,legs and ears. This is also known as “shape-shifting”. The effect, however, won’t happen to all species – some will manage to evolve whereas others will remain how they are and can even become extinct as a result.
“The climate change that we have created is heaping a whole lot of pressure on them, and while some species will adapt, others will not.”
Sara Ryding of Deakin University, Australia
Of course, climate change is a rather complex phenomenon whereby it is hard to pinpoint what really causes a change in the structure of animals. It has been noticed that the shape-shifting effect is occurring to a wide range of species amongst wide geographical regions, where little is common except the global effect of climate change.
A strong pattern of shape-shifting has been particularly found within birds. Several parrot species of bird within Australia have shown a 4-10% increase in bill size since 1871- with a positive correlation between bill size and annual summer temperatures. The North American dark-eyed junco – a type of small songbird- has a correlation between increased bill size and short-term temperature extremes within cold environments. Researchers have also actually reported evolutionary changes in mammalian species. It has been reported that there has been an increase in tail size of wood-mice and of leg size in masked shrews.
“The increase in appendage size is hardly noticeable- less than 10%. This means that changes are likely to be unnoticeable till a long time later. Research does show that prominent appendages are meant to increase, such as the ears.”
Ryding
There are lots of anatomical changes occurring to all sorts of species- but what about humans? How will it affect us?
Inside the body
Viruses such as malaria and the West Nile virus would spread to more temperate temperature zones and spread more than merely confining their habitats within tropical climates. This means that a higher proportion of the world would have such outbreaks – who knows, in the future even colder climate habitants could end up living with these diseases. As a result of being exposed to these diseases, our immune systems will need to create new defences.
Did you know?
Sickle cell anaemia and thalassemia patients are resistant to malaria!
This in turn may mean that more people will acquire such diseases as an effect to fight against malaria and such diseases.
Climate Change may also cause a change in global food availability- which will also have an impact on humans. The ability to digest milk within humans actually derived from habitants of the Middle East and North Africa, who began to raise cattle. Future generations may be able to evolve more tolerance to other types of substances that perhaps we aren’t tolerant to. This will happen as a result of limited foodstock due to the effects and impacts of climate change.
Changes in diets may also trigger microbiomes- the microorganisms that live in our gut to help keep us healthy. It has been proven that vegetarians have a different mix of microbiomes in comparison to people who have meat in their diets.
External Changes
Climate change could reduce racial differences as it may trigger massive migrations. In recent decades more people like to live in urban areas, 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. And as droughts become more common and more severe, people living in more arid areas will have to move to places with more reliable sources of water.
These migrations will merge together geographical barriers which once separated human populations. This process, as a fact, has already started: as of 2017, 258 million people are living in a country they weren’t born in – this is an increase of 49% since 2000.
“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 especially likely to migrate.”
A consequence of large-scale migration is gene flow. This is a type of evolution caused by the blending of genes between populations. When people from different populations interbreed this leads to intermingling of genes within children, hence they may show traits neither seen in parents or their populations. For example, Cape Verde islanders have dark skin and blue eyes – this is a result of interbreeding between Portuguese and West Africans.
Shifting in skin colour
One of the most obvious effects of climate change could be a similarity in skin colour. Skin color differences is actually a result of natural selection in different human populations. The pigment Eumelanin makes skin darker in tone, which helps protect against harsh sunlight. But too much Eumelanin can make it hard for the body to produce vitamin D, which is needed to build healthy bones, hence such people may develop bone diseases. 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 can indirectly cause bone deformities) versus having too little (which can lead to cancer and birth defects).
As a result, skin color came to closely match the intensity of sunlight in different regions — darker near the equator and lighter near the poles.
Nowadays, sunscreen and vitamin supplements are common, hence natural selection is less relevant to ongoing changes in human skin pigmentation than gene flow. Because skin color is controlled by alleles and their phenotypes, parents whose skin color differs tend to have children with intermediate skin tones. And so in five to 10 generations (125 to 250 years), we may see fewer people with dark skin or pale skin and more with a brown or olive complexion. Having both dark skin and light eyes may become more common.
Blending of races is already well underway in ethnically diverse countries like Brazil, Singapore and the UK.
Did you know?
The multiracial population is projected to grow by 174 percent over the next four decades.
And for all you know, as people in future generations become more and more similar to one another, there may be a possibility that racism could fade.
As climate change brings about rising temperatures, droughts and shifts in precipitation patterns, plants and animals are changing their structural features (and appearance even) to keep up with the pace of their changing environment. This will of course have impacts on our living habits – both advantageous and disadvantageous. The question is how well our sources of resilience as species will succeed as we have alterations in our landscape, atmosphere and water levels as our Earth’s climate shifts. This ‘experiment’ is just unfolding, and is one which has never occurred before. This is because the intensity of environmental change seems likely to create entirely new survival challenges for us on the planet, and for many other organisms as well.
https://humanorigins.si.edu/research/climate-and-human-evolution/climate-effects-human-evolution
https://www.sciencedaily.com/releases/2021/09/210907110718.html
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