Body Shape
Adaptation to climate is the cause for some of the most noticeable differences in human body shape.
Warm-blooded animals in warmer climates tend to maximize surface-area-to-volume ratios to facilitate cooling, whereas those in colder climates tend to minimize surface-area-to-volume ratios to retain heat. This relationship is called Allen's Rule. A similar principle called Bergmann's Rule observes that, within a species, populations which live in colder climates tend to be more massive than those which live in warmer climates. In practical terms this means that humans adapted to warm climates tend to be slender, and humans adapted to cold climates tend to be stocky.
One of the most visually-stunning differences caused by climatic adaptation is found in limb proportion. Warm-adapted populations have proportionately longer limbs and shorter torsos compared to cold-adapted populations. This difference remains even when a given cold-adapted population is, on average, taller than a given warm-adapted population.
For example, take the image below. It shows 6 Australian women of the same weight (70 kg/154 lbs). The middle four women are approximately the same height. It is immediately noticeable that the second woman from the left has much longer legs than anyone else of the same height. Her legs are nearly as long as the tall woman on the far right!
Let us examine this in more detail. Since we are concerned with the proportion of torso and limb length--not their absolute size--I have edited the image so the two women on the far left and right are approximately the same height as everyone else. Now that height is fixed, we can visually compare the variation in torso and limb proportions. In the image below, the top two lines indicate the length of the torso. The bottom line marks the length of the arm.
We can see that the woman with the highest degree of warm-adaptation (marked in red) has a significantly shorter torso than any of the other women. Her arms are only slightly longer than everyone else's, but the distance from the end of her torso to the end of her arms is much greater. Indeed, while all of the women marked in blue have torsos that end roughly around their wrists, her torso ends about halfway through her forearms!
The next image is of basketball players Manute Bol and Muggsy Bogues. Bol is 2.31m (7ft 7in) tall, while Bogues is 1.60m (5ft 3in). In the image, the length from the top of their head to the end of their torsos is about the same (Bol is slightly larger), so instead of scaling them to the same height we can simply compare them as is.
From the image we can gather that Bol is as tall as 9 basketballs, while Bogues is as tall as 6.5. Bol's legs are the equivalent of 5.75 basketballs, while Bogues' are 3.5. This means that Bol's legs make up about 64% of his total height, while Bogues' only make up 54% of his. Obviously this method of measurement is not perfect, but it serves as a useful visual aid to demonstrate that Bol is not merely a taller version of Bogues--he has fundamentally different proportions due to a higher degree of warm climate adaptation. And as we saw previously with the Australian women, the proportions of an individual's limbs and torso do not depend on height, but on climatic adaptation consistent with the predictions of Allen's Rule.
Body Shape and Somatotypes
While the evolutionary origin of different body shapes (somatotypes) is likely more complex than simple warm or cold adaptation, one can't help but notice that Allen's Rule seems to do a good job predicting the archetypical differences in human body types.
One of the most well-known and widely used classification of body types comes from William Herbert Sheldon's classification of somatotypes. He recognized that humans tend to cluster into three different body shapes or types (Ectomorphic, Mesomorhpic, and Endomorphic), and classified individuals by giving them a number from 1-7 in each category (i.e. 1-1-7 is a pure Ectomorph, 1-7-1 is a pure Mesomorph, 7-1-1 is a pure Endomorph, and 4-4-4 is midway between all three categories). This 3-fold classification is still used in modified form today, most notably by the Heath-Carter Formula, which provides a rigorous way to calculate an individual's somatotype. German psychiatrist Ernst Kretschmer developed a similar tripartite classification of body types around the same time as Sheldon. (Kretschmer's definitions were influential in German anthropology during the first half of the 20th century, but Sheldon's definitions continue to be better known in the English-speaking world).
For us, an individual's precise three-number classification is not very important. The important takeaway is that, just like face shapes, most individuals are a mix between the archetypical body types. Additionally, while it is possible that some somatotype/face shape combinations are more common than others, no somatotype is exclusive to any single face shape.
Sheldon and Kretschmer attempted to correlate somatotype with personality and psychological traits (as people have been doing for millennia), and more recently some circles on the internet have attempted to synthesize somatotype with Myers-Briggs personality types. However, we must admit that just as we cannot make conclusions about an individual's personality solely from looking at their face shape, neither can we deduce an individual's personality solely from their body shape. We merely claim that those who possess Aryan blood memory will find an Ectomorphic body with an Oval face to be the most aesthetically-pleasing combination of traits.
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Most discussions involving somatotype on the internet focus on its implications for body builders and fitness junkies, but it is rarely discussed why such differences in somatotype biologically exist in the first place. Consistent with Bergmann's Rule and Allen's Rule, warm-adapted individuals tend to be lean Ectomorphs and cold-adapted individuals tend to be bulkier non-Ectomorphs.
Among sports enthusiasts, it is well known that Ectomorphic individuals excel at aerobic stamina-based events such as running, whereas non-Ectomorphic individuals (yes, this includes Endomorphs) excel and anaerobic strength-based events such as weight lifting.
Thinking that they are making some profound anthropological observation, WNs like to point out that "blacks" seem to dominate Olympic running events, while "whites" win more frequently in other areas. However, if we look at the physique of the world's top runners, we find that they tend to be Ectomorphs (regardless of skin color or ethnicity), while athletes who succeed in anaerobic strength-based events tend to be non-Ectomorphic (regardless of skin color or ethnicity). The fact that dark-skinned individuals tend to be more warm-climate adapted on average than light-skinned individuals should not be surprising, as Earth's warm tropical regions receive the highest amounts of UV radiation and Earth's colder areas tend to receive lower amounts of UV radiation. (See the final section of this article for more detail).
External link: Image gallery of various Olympic athletes' body types
Facial Features
While body shape and limb proportions are the most important traits in determining whether an individual is warm-adapted or cold-adapted, there are a number of facial features which can offer clues.
One of these features can be seen in the eyes. A fold of skin covering the upper eyelid is generally considered to be a sign of cold adaptation. This fold is properly called an epicanthic fold when it covers either corner of the eye, and is sometimes referred to as having "hooded eyes" when it covers the top of the eye, but only slightly in the corners. Fashion websites sometimes say an eye with an epicanthic fold has a "monolid" look, but this is misleading because everyone has an upper eyelid and lower eyelid. Individuals with strongly hooded eyes merely have the skin crease on the upper eyelid obscured by the hood or have skin pulled so tight and eyes so non-deep-set that a crease does not form.
This extra layer of skin and fat helps shield the eye from the cold. While this trait is most commonly found in the Sinosphere (even occurring in many individuals who are ectomorphic or have other signs of warm adaptation), it can also be frequently found in cold-adapted Europeans and, to a lesser extent, individuals from various ethnic groups around the world. Features such as a low-bridged nose and wide set eyes generally accompany this trait and are possible underlying anatomical causes of epicanthic folds/hooded eyes, beyond being exclusively due to environmental adaptation.
Deep-set eyes can contribue to the "hooded" look by obscuring part of the crease of the eyelid when viewed from certain angles (making the eyelid appear to have a fold over it), but having deep-set eyes is not the same thing as having a skin fold. Additionally, some individuals only develop a fold over the eyes as they age and their skin starts to sag; this is not a "true" epicanthic fold either, although those with some degree of "hoodedness" while young are more likely to have this feature become accentuated as they age.
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The shape of the nose is also affected by climate, although it is a bit more complex than a simple "hot vs cold" classification. Aquiline, or "beak-like", noses are an adaptation which tend to be found in excessively-dry warm and cold environments (both of which are non-arable), as they provide a larger region for air to be warmed and humidified before being transfered to the lungs. This nose shape gives an individual a protruding profile, although not all aquiline noses (especially those in cold climates) protrude to an extreme degree. This nose shape often appears very long and thin when viewed from the front.
This is something originally observed by physical anthropologists a century ago, and 21st-century studies have confirmed the validity of earlier anthropologists' observations.
External link: Link between nose shape and climate
Nose shapes in warmer, non-arid climates have a higher degree of variation. In excessively humid climates, the nose tends to be wider and have a low nasal bridge. Noses from more temperate climates often have nasal bridges of moderate height. People with longer faces (e.g. Ovals and Oblongs), tend to have correspondingly longer noses, and thus are more likely to have moderate nasal bridges, rather than short and low-bridged "snub noses".
Again, we must emphasize that an individual's overall body shape is a much better indicator of climatic adaptation than a single facial feature.
Pigmentation
Although pigmentation itself is correlated with the amount of UV radiation a region receives (highest at lower latitudes)--not climate--it just so happens that Earth's high northern latitudes tend to have cold winters and the low latitudes tend to be warm year-round. This pattern was taken to the extreme during the last ice age (approximately 110,000 to 12,000 years ago), which shaped human evolution during the final millennia of the Paleolithic era.
Because of this apparent correlation between light pigmentation and "northernliness" (especially in Europe and India), pigmentation has been associated with climate by many racist ideologies, most notably Nordicists/Hyperboreanists/White Nationalists (or whatever they are calling themselves these days).
Historically, this mis-association has been exacerbated by "Gloger's rule," which observes that pigmentation correlates with warm humid areas. It is no coincidence that regions with this type of climate tend to be located near the equator--solar radiation is responsible for creating warm temperatures and solar radiation is most intense at the equator.
Interestingly, skin pigmentation in Europe was, on average, darker amongst Paleolithic hunter-gatherers (who had blond hair, and likely light eyes), than it is today. UVB radiation is critical for producing vitamin D, and as a result, many individuals with dark pigmentation suffer from vitamin D deficiency if they live in high latitudes. However, vitamin D can also be obtained from diet. Indeed, many Inuit populations have very dark skin, despite living at some of the highest latitudes on Earth, because they obtain most of their vitamin D requirements through their meat-heavy diet.
It was only after farmers (who receive less vitamin D from their plant-heavy diet) came to Europe in the Neolithic era that there was significant selective pressure to further lighten skin color. Importantly, these farmers brought with them a different type of light pigmentation than the type possessed by light-skinned hunters. These farmers, who evolved in the mid-latitudes where seasonal UV radiation varies, had the ability to tan, which is lacking in the 'milky white' skin tone which WNs cherish so much.
While traditional depictions of the "Nordic race" portray blond people with Oval faces and slender bodies, in reality most blond inhabitants of Nordic countries are wide-faced and stocky. Contemporary WNs continue to conflate the Neolithic and Paleolithic populations of northern Europe into a single group, such as Richard McCulloch's concept of a "Nordish race"--which claims to be based upon scientific studies of "race," yet deems the huge genetic and phenotypic difference between Neolithic and Paleolithic northern Europeans to be trivial!!!
The bulk of blond northern Europeans and members of the so-called "Nordish race" are actually descendants of Paleolithic survivors, not Neolithic Aryans. Anthropologists have known this for nearly a century, with those such as Carleton Coon acknowledging that the light-pigmented, Oval-faced, Ectomorphic part of the so-called "Nordic race" is skeletally identical to the warm-climate-adapted and darker-pigmented "Mediterranean race" which also extends into the Egyptosphere, Persisphere, and Indosphere.
"In Europe, the Neolithic is primarily the period of the Mediterranean race, in one form or another. It was, apparently, the Mediterraneans who accomplished the change to a food-producing [i.e farming] economy elsewhere, and who expanded into the territory of the food-gatherers [i.e. hunter-gatherers].
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By Mediterranean, in the skeletal sense alone, we mean the wide family of closely knit racial types which are long headed, orthognathous, mesorrhine or leptorrhine, narrow faced, and of medium head size... It differs from the major Upper Palaeolithic group of Europe and northern Africa in several respects." -Carleton Coon
Warm-adapted Neolithic farming populations migrated from the Mediterranean region long after the glaciers melted. Descendants of these warm-adapted Neolithic farmers can today be found in even the coldest and most northernly parts of Europe, but neither this nor pigmentation nor present-day cultural similarity changes the fundamental fact that cold-adapted Paleolithic-descended populations are genetically and phenotypically distinct from warm-adapted Neolithic-descended populations.
"It is impossible, as some European anthropologists believe, to derive a Nordic directly from a dolichocephalic Upper Paleolithic ancestor of Bruenn or Cro-Magnon type. Reduction of these overgrown races produces a result which is quite un-Nordic morphologically as well as in constitutional type. It is the author's thesis that the Nordic race in Europe was caused by a blending of the early Danubian Mediterranean strain with the later Corded element." -Carleton Coon