Ensemble Model
Ensemble Model
[Inside this single panel comic the header on top reads:] In an ensemble model , forecasters run many different versions of a weather model with slightly different initial conditions. This helps account for uncertainty and shows forecasters a spread of possible outcomes.
[To the left side a picture shows several gray overlapping swirling lines emitted from a point, then gradually diverging rightwards. Below are two smaller pictures; the first shows the lines connected to several loops and in the second it's still a similar figure to the above but moving into the opposite direction with the point emerged to a spiral.]
[The text right to the pictures reads:] Members in a typical ensemble: A universe where… …rain is 0.5% more likely in some areas …wind speeds are slightly lower …pressure levels are randomly tweaked …dogs run slightly faster …there's one extra cloud in the Bahamas …Germany won WWII …snakes are wide instead of long …Will Smith took the lead in The Matrix instead of Wild Wild West …swimming pools are carbonated …sliced bread, after being banned in January 1943, was never re-legalized.
2149: Alternate Histories also deals with the alternative history setting of Germany winning WW2 and subsequently more weird alternate history settings.

An ensemble model is a combination of multiple, similar models to show a wider range of possible outcomes. The graphs on the left are tracks of predictions from multiple models.  In this comic, Randall starts out describing actual changes that ensemble models show, but sinks into absurdity, describing strange alternate universes and scenarios that likely would not be necessary in an actual model.
The upper graph shows a typical plot of predicted wind speeds over time from various ensemble members. The graph shows that it is predicted that the storm will strengthen, with varying degrees of weakening depending on the ensemble member. The graph at the left bottom is a typical map of isobars (lines of equal pressure ) for various ensemble members with the ensemble members showing slightly different configurations. The bottom right graph is a typical hurricane path-prediction graphic, starting in the Atlantic moving westwards and then turning to north, often with the Caribbean Islands or the US coast in the path. Some hurricanes don't reach mainlands and after turning north they head eastwards and can reach Europe still as strong storm.
The term universe is in mathematics a class that contains all the entities of an ensemble in a given situation. Don't be confused with the more common usage of the words universe , the entire space where we live, and multiverse , a hypothetical set of possible universes.
The first three outcomes are real while the others are less serious. They are explained below:
…rain is 0.5% more likely in some areas …wind speeds are slightly lower …pressure levels are randomly tweaked
These realistic outcomes are only possible under calm weather conditions. Predicting these values with an accuracy better than 1% indicates that the model is stable even when the initial conditions are slightly changed. Modern weather forecasts at normal circumstances are often not good as this and for a hurricane or tornado the variances are much higher.
…dogs run slightly faster
This is where the comic diverges from reality; there is no reason to have the locomotion speed of dogs as a parameter in a usual weather model [ citation needed ] .
The speed of dogs might be a parameter in a wildlife model, where the speed of a predator might affect the predator/prey ratios.  In terms of weather models, dogs traditionally chase cats, so running faster might affect the number of cats.  Cats prey on birds, which in turn eat insects.  So faster dogs might increase the number of birds, reducing the number of butterflies.  Butterflies in turn affect the weather through the butterfly effect (that is that the movement of a butterflies wings may change the development of tornados, or other weather, in difficult to predict ways, as for instance with the quantum weather butterfly ).
…there is one extra cloud in the Bahamas
This situation is most likely too specific and subtle a difference to be useful to the model.
…Germany won WWII
"What if Germany won World War II" is a very popular subject for alternate history stories.
…snakes are wide instead of long
Snakes being wider than they are long (think "eyes and mouth in the middle of their body and a tail on both sides") in present reality would have enormous consequences for zoology and other fields of biology, including evolutionary biology. It would also have an impact on art history, especially where it involves paintings depicting certain scenes from  the book of Genesis. Compared to these effects, the expected upshot for meteorology seems to be limited.
…Will Smith took the lead in The Matrix instead of Wild Wild West
Actor Will Smith famously [ citation needed ] turned down the lead role of Neo in The Matrix , instead taking the role of Captain James T. West in the widely-panned action-comedy Wild Wild West . The role of Neo ultimately went to Keanu Reeves .
Besides the significance of the role and what many surmise might have happened if Smith had pulled off the role in the iconic and groundbreaking film trilogy, another possible reason behind calling out Will Smith in particular is that he has turned down other offered roles that would place him in an ensemble cast, rather than the lead.
…swimming pools are carbonated
A simple calculation reveals this as a serious greenhouse problem. In the United States alone there are no less than 5,000,000 private owned pools. Conservatively assumed, a volume of 25,000 liters per pool gives 125 billion liters of carbonated soda. According to Wikipedia the U.S. sales reached around 30 billion bottles of water in 2008 (including non-carbonated water) which is much less than all of the pool water. While all those bottles are not considered to have an impact on the greenhouse effect, this scenario gets even worse. Open a bottle of carbonated water and pour the content into a glass. Sooner or later the bubbles fade, meaning you have to open the next bottle and pour it in and so on. In a pool at the bottom the pressure is high enough to hold the carbon dioxide, but on the surface it behaves like the glass. So, while a glass needs new carbonated water every two hours, or ten times per day, it would be about three times per day for the pool, which leads to 1095 times per year. The total number in this scenario would be 125 trillion liters of carbonated soda, ejecting carbon dioxide, per year. Even taking into account the pressure at the bottom of the pool: Randall has shown in Soda Sequestration this effect would be minimal.
…sliced bread, after being banned in January 1943, was never re-legalized.
Sliced bread was in fact banned in the US for about two months in early 1943, as a supposed wartime conservation measure. The issue was not the bread itself, but that the pre-sliced loaves required a heavier wax paper wrapping to prevent them from drying out too quickly.
The title text suggests that Randall has been pitching an absurd "alternate-universe crime drama" to Netflix , apparently based on the premise that a permanent sliced-bread ban would spawn a criminal underground (similar to those created by alcohol and drug prohibitions in actual history). The first half of the sentence is set up to imply that production had started on the series but a breakdown in communication has occurred between them, playing on the reader's expectations. The conclusion of the sentence nonetheless makes it clear that Netflix has zero interest in the pitch, and so Randall has become overzealous in pushing his idea, to the point that Netflix employees are changing their numbers (presumably they can't block his number because he has resorted to calling from many different phones). He has even taken to infiltrating Netflix's corporate headquarters using ill-gotten security codes, which is definitely illegal [ citation needed ] , much like Elaine 's "meetings" with Steve Jobs in 1337: Part 3 .
However, it is clear that Netflix is uninterested and is attempting to prevent Randall from contacting them (or trespassing into the building).
[Inside this single panel comic the header on top reads:] In an ensemble model , forecasters run many different versions of a weather model with slightly different initial conditions. This helps account for uncertainty and shows forecasters a spread of possible outcomes.
[To the left side a picture shows several gray overlapping swirling lines emitted from a point, then gradually diverging rightwards. Below are two smaller pictures; the first shows the lines connected to several loops and in the second it's still a similar figure to the above but moving into the opposite direction with the point emerged to a spiral.]
[The text right to the pictures reads:] Members in a typical ensemble: A universe where… …rain is 0.5% more likely in some areas …wind speeds are slightly lower …pressure levels are randomly tweaked …dogs run slightly faster …there's one extra cloud in the Bahamas …Germany won WWII …snakes are wide instead of long …Will Smith took the lead in The Matrix instead of Wild Wild West …swimming pools are carbonated …sliced bread, after being banned in January 1943, was never re-legalized.
2149: Alternate Histories also deals with the alternative history setting of Germany winning WW2 and subsequently more weird alternate history settings.
