Greetings fellow smallfolk. Well here we are, Season 6, several Starks shorter and Lannisters lighter since last we spoke. Winter is, for all intents and purposes, actually here and life looks pretty bleak on both sides of the Narrow Sea. The only thing we can trust is George R.R. Martin's eternal power to crush our hopes and dreams like that Lannister cousin smashing beetles in the garden.
Even though Ramsay has Rickon and Gendry is probably still rowing in circles, all is not lost. Jon Snow may be undead but the science in GoT is very much alive.
#1 Greyscale
Probably based on leprosy.
In the GoT universe, greyscale is a highly contagious and usually fatal skin disease that turns living flesh into cracked, stone-like scales. Afflicted persons known as "Stone Men" are exiled from society to live in creepy Valyrian ruins. These poor souls can live for years with the condition before the disease attacks the internal organs and the brain, resulting in madness and ultimately death.
One can't help but notice the similarities between greyscale and leprosy. Like greyscale, leprosy is a long-term infection that can lead to severe skin deformities. However, perhaps the greatest similarity between the two diseases is the social stigma. A potential biblical mistranslation refers to a relationship between certain skin afflictions and spiritual impurity. As a result, medieval Christian communities banished lepers from their midst. Ostensibly, GoT is based on medieval/early modern England so this thinking aligns with Westerosi feelings towards greyscale. Indeed, wildlings deem survivors of greyscale "unclean" and many people fear that the disease is merely dormant in these individuals.
However, this where the resemblance ends. Unlike greyscale, leprosy is, perhaps surprisingly, not very contagious and probably not spread by touch. We now known that leprosy is caused by the bacteria Mycobacterium leprae and Mycobacterium lepromatosis rather than a supposedly polluted soul (shocking I know). There is also no evidence whatsoever that leprosy infection has any effect on a patient's mental state.
#2 Crazy Seasons
Probably based on Milankovich cycles.
GoT weather is, shall we say, unpredictable. Their seasons don't follow an annual cycle but rather last for years at a time and are totally irregular in length. Supposedly, there once was a generation-long winter, the idea of which is about as appealing as a date with Ramsay Bolton.
*Let me preface the rest of the explanation by saying that Milankovich cycles are NOT a valid explanation for global warming and those that cling to this debunked theory are willfully ignorant troglodytes.
To put it simply, Milankovich cycles are long-term variations in the Earth's orbit, tilt, and direction of its axis that influence our climate. These small changes change the amount of sunlight that reaches the Earth, thus leading to extended and predictable climate cycles. Milankovich cycles occur about every 21,000, 41,000, 100,000, and 400,000 years and are responsible for glacial (ice-age) and interglacial (warmer) periods.
These cycles have hugely influenced human evolution. In fact, this last ice age was almost responsible for our extinction. Genetic evidence suggests that the cold weather cut our numbers to less than 10,000. However, we managed to come back from near annihilation around 70,000 years ago and spread beyond Africa.
It is not out of the realm of possibility that the world of Westeros and Essos has its own Milankovich cycle situation. Obviously it would need to be far faster and more dramatic than our own but hey, this is a planet with dragons.
#3 The Strangler
Probably based on strychnine.
Remember when Joffrey was killed and the world rejoiced? That happy moment was brought to you by the strangler, a rare and deadly poison made from a plant found on islands in the Jade Sea. To make the strangler, leaves from this unnamed plant are aged and then washed in lime followed by sugar water supplemented with spices. Eventually, the leaves are discarded and the remaining liquid is thickened with ash and allowed to crystallize. Like its name implies, the strangler causes the throat muscles to swell shut so the victim asphyxiates (never mind all the bleeding orifices).
If you thought such a crazy poison could only be found in fiction you'd be dead wrong (pun intended). Strychnous nux-vomica or the strychnine tree is the source of an eerily similar toxin: strychnine. Found in southeast Asia, seeds from this tree contain the highly poisonous alkaloid strychnine. A mere 15 minutes after ingestion, strychnine causes muscle spasms beginning in the face and neck.
Even the strangler's preparation matches strychnine. Instead of the fruit, lime could refer to "quicklime" or calcium oxide. Calcium oxide is widely used and highly alkaline which means it is very basic (has a high pH). This type of compound could easily be used (indeed it has been used) to extract alkaloids (which are also highly basic) from plant material. Another nail into the coffin (I'm on fire with these puns!) is the sugar/spice wash. Alkaloids like strychnine are really bitter so it makes total sense that you'd want to mask the taste with strong flavors like sugar and spices.
#4 Direwolves
Probably based on dire wolves since they ACTUALLY EXIST!
Sorry, by "exist" I mean existed. Dire wolves were very much real but they are unfortunately now extinct. Direwolves in GoT are pretty much just giant wolves that live in the north. That's essentially what we know about them aside from the fact that they are fiercely loyal to their owners.
It appears that the only major difference between Earth dire wolves (Canis dirus) and GRRM's direwolves is the size. In GoT, direwolves can grow to the size of a small horse. In reality, C. dirus was only slightly larger than extant gray wolves and about 25% heavier.
Like today's wolves, dire wolves were social animals that hunted in packs. Fossil records indicate that they went extinct about 10,000 years ago along with most other American megafauna. This date coincides both with the end of the last glacial period (see #2 Milankovich cycles) and the arrival of humans to dire wolf habitats. From this, we can infer that dire wolf extinction was probably a combination of climate stress (disappearance of prey animals) and human hunting. Whatever the cause I think we can all agree that this is a huge bummer.
So there you have it! Science continues to be an undercurrent of the GoT universe. Why make something up when real life is just as weird and amazing if not more so? Except dragons. Real life really lacks in dragons.