Chronicles of climate change

 By Alessandra Pierro

The final series of Game of Thrones, as everyone knows, recently ended amid controversy and disappointed fans. Yet, for eight seasons, it seemed that no TV series had ever entered our imaginations in such a profound way…

Along with its rich symbology, the surprising thing was the endless historical and scientific references. In A Song of Ice and Fire – the epic fantasy by George R. R. Martin, from which the TV series was adapted – there are various details that seem rooted in reality (aside from a few often not insignificant aspects).
These include the infamous Wall, inspired by Hadrian’s Wall, built by the Emperor in the 2nd century between the Roman province of Britannia and Caledonia (Scotland), to separate the Romans from the barbarians. In addition, the direwolves ­– proportions aside – recall Canis Dirus, an ancestor of the grey wolf dating back to the Pleistocene.
GoT is strewn with historical references, and many of the battles recall the background of the two European wars at the end of the Middle Ages. The War of the Roses, in particular, fought in England (1455-1485) between the Yorks and Lancasters, may have been the inspiration for the houses of Stark and Lannister.

The Hadrian's Wall

From Westeros to Greta Thumberg

But there’s more. On closer inspection, the saga may even draw on certain historical periods that experienced climate variations, set against a background – probably the Hundred Years’ War between France and England (1337-1453) – that is inspired by the dawn of the Little Ice Age. In this period – which climate scientists consider to be the coldest stadial phase of the current interglacial period – there was a dramatic fall in temperatures across various parts of Europe and such harsh winters that harvests were destroyed and famines were frequent. Very similar to the dreaded winter coming to Westeros. On the other hand, the long period of high temperatures that precedes it in the series recalls the so-called Medieval Warm Period, between the 9th and 14th centuries. The extent of cooling and warming during the middle ages is still the subject of scientific debate, part of a wider discussion on climate change, particularly within the context of the “hockey stick” controversy, which warrants a brief explanation.
The question emerged at the end of the 1990s, when researcher Michael E. Mann published the results of his study on climate variations in the Geophysical Research Letters journal. Soon after, his graph appeared in Nature, sending out shockwaves to the scientific community: studies of thousands of years of data showed an almost constant average temperature until 1850, then, immediately afterwards – following industrialisation and the progressive use of fossil fuels – it soared upwards, to give a curve like a hockey stick.

The "Hockey stick" graph by Michael E. Mann

This was seen to be scientific proof of the magnitude of the impact of human activity on climate change. Mann’s data thus created a split, in part still ongoing today, between those who attribute global warming to human factors and those who cite natural causes. For the latter, the Medieval Warm Period – with an average temperature similar to that at the end of the millennium – backed up their theory that global warming was caused by a natural climate cycle and not, therefore, by greenhouse gases.
Today, however, the data points to the fact that the temperature rises are mainly caused by fossil fuel combustion and that this is what underlies the current climate change. If temperatures rise above 2°C relative to the pre-industrial period, there is a risk of an increase in abrupt and irreversible atmospheric changes, extreme events such as typhoons and flooding, as well as droughts and fires. Our house is on fire, warns young Greta Thumberg: was she echoing the Starks’ enigmatic motto?

Winter is coming (and this is not fantasy)

One of the more interesting interpretations doing the rounds sees Game of Thrones as an allegory of climate change, in which the arrival of the White Walkers could unfortunately evoke something a good deal more real than creatures invented by the pen of a fantasy writer.
As true fans of the series know, one of the problems gripping Westeros is its climate, and this unpredictable seasonal volatility has even intrigued scientists. Researchers from the University of Cardiff, Bristol and Southampton have indeed demonstrated that the climatic conditions of Westeros, albeit rather difficult to imagine, would not be completely implausible from a scientific point of view. The study results were published in “Philosophical Transactions of the Royal Society of King’s Landing” (a specially-created journal, although the article can be downloaded from the University of Bristol website).
Unable to reproduce the climate system in the laboratory, climatologists used climate models to simulate the climate and its evolution. A climate model is a kind of virtual laboratory integrated with mathematical models and supercalculators, based on fluid mechanics. Air and water are divided in boxes, between which heat flow, and velocity and mass are calculated according to a time progression. To study the Game of Thrones climate, the CitCM3 climate model was used, whereby a set of algorithms can simulate the climatic evolution of any planet for up to 200 years, once the so-called boundary conditions have been set, i.e. its main features (distance from the sun, axis inclination, position of its continents, land height and sea depth and greenhouse gas concentration).
To proceed with the simulation using parameters from the GoT world, the researchers set values similar to the Earth’s, then partly modified them by adding data extrapolated from Martin’s books (the autumn storms, night temperatures similar to day temperatures and the long, harsh winters of Westeros). Lastly, using the map of the known World for reference, the continents and mountains were plotted and, after converting it all into digital form, the data was entered into the climate model.

Climate model on sea level pressure and world winds of Game of Thrones, color scale shows pressure in millibars (Dan Lunt, University of Bristol)

One of the difficulties was the changing seasons and their length, factors determined by the inclination of the Earth’s axis of rotation; to make the model’s predictions coincide with the seasons of GoT, the angle of inclination, of about 23°, was reduced to 10°. Another factor that could contribute to seasons like those in Game of Thrones would be an unstable axis of rotation (the Earth’s is stable due to the Moon). The simulation revealed that in the Wall region there would be winter temperatures and precipitation similar to those of Lapland or Alaska, while the climate of Casterly Rock, stronghold of the Lannisters, would be closer to some regions of China and Texas, with hot summers and mild winters.
In addition to explaining the plausibility of seasons and weather conditions such as those in GoT, the study measured the climate sensitivity, a parameter that calculates global warming based on emissions, which in this case was 2.1°C.
Seen this way, the places illustrated by Martin, do not seem so different from real ones…


Image cover copyright HBO

READ MORE: Supercomputer vs Climate Change by Eniday Staff

about the author
Alessandra Pierro