1732: Earth Temperature Timeline

Explain xkcd: It's 'cause you're dumb.
Revision as of 11:20, 13 September 2016 by 108.162.229.49 (talk) (Removing pointless trivia about black body color, since it's clearly not related to the comic.)
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Earth Temperature Timeline
↓ Skip to explanation ↓
[After setting your car on fire] Listen, your car's temperature has changed before.
Title text: [After setting your car on fire] Listen, your car's temperature has changed before.

Explanation


Ambox notice.png This explanation may be incomplete or incorrect: Table for explanations now ready to be filled out. Please remove this tag only when everything is explained.
If you can address this issue, please edit the page! Thanks.

In the past 100 years, human action produced lots of CO₂ emissions, which have caused a rise in average global temperature through the greenhouse effect. This is called global warming and is part of a climate change, a subject that has become a recurrent subject on xkcd. There are still many people who claim that this is not happening, or at least that it is not caused by any human actions, called "climate change deniers". One argument of theirs is that global warming is happening for natural causes, summarized with the phrase "temperature has changed before". This comic is a direct, but much more thorough, follow up on the previous global warming comic: 1379: 4.5 Degrees.

This comic shows that while temperature changes have indeed occurred before, the speed of the current temperature rise is much, much faster than those seen (actually: estimated) in the previous thousands of years.

This comic is a timeline on how the temperature has changed since 20,000 BCE to the present day and extrapolated 84 years on from present day of the release of the comic (2016) to 2100 depending on the choice of actions to stop CO₂ emission that is taken now or never. It is meant to contrast the slow-paced natural changes with the rapid temperature rise in the recent years. The effect is achieved by forcing the reader to scroll endlessly through slow, building-up changes and then face them with an almost instantaneous, quick rise towards the end. The temperature curve is a dotted line most of the time, but from about 1850 to present day (2016) the measurement data is good enough to let the curve become a solid line indicating that this is not an estimate. Before 1850 the temperature is an estimate bases on the sources given. And likewise into the future the curve is also dotted as this is predictions. And here there are even three possible outcomes depending on how seriously politicians and other influential people (and the population of Earth) take knowledge (and comics) like this.

Below in the table each entry will be noted and explained (in time). This is one of the comics where Randall cites his sources like he did for one of his other very large comics 980: Money.

The title text compares the saying that "the temperature has changed before" comparing temperature changes over thousands of years to the rapid global warming over the last century with saying that the "small" changes to the temperature a car experiences over the years of normal usage should not make you worried over the rapid temperature increase that happens when someone burns your car. A related joke was used recently in 1693: Oxidation.

Table of all elements

  • Here is table (to be filled out) of all elements with explanations including reading of temperature and year for each event from the curve.
  • Table ready for use:
    • The year group is just an easy way to find the section.
    • The actual year of an event should be read off more precisely on the chart.
      • Suggestion for doing this:
      • Top part of element
      • Central part of element
      • Other?
    • Element is a description mainly taken from the transcript. Feel free to remove redundant information, but the guess was that getting the table ready was the most important feature for getting the explanation started.
    • T (°C) should be read of for the curve for every element.
    • Explanation explains itself.
Year group Element Year T (°C) Explanation
20000 BCE [An arrow goes from the dotted line to the central line at 0°C. In the middle of the line there is a temperature label:] 4.3°C
At the start of our timeline, 22,000 years ago, Earth is 4°C colder than during the late 20th century.
20000 BCE -4.3 The temperature at the beginning of the chart compared to the average from 1961-1990 that we compare temperatures with today.
Boston is buried under almost a mile of ice, and the glaciers reach as far south as New York City.
[The Statue of Liberty is shown in front of a glacier front. A guy with a white knit cap is seen walking in a snowy landscape. The skyline of Boston is shown under a half a mile of ice.]
19700 BCE -4.3 The Boston image is directly taken from 1225: Ice Sheets about the ice age glacier coverage and the guy with the white knit cap could be the guy from 1321: Cold also about global warming. It shows what a difference 4 degree in global temperature means (massive effect), as opposed to what four degree means on a daily weather wise scale (nothing!). Randall lives in Boston. It was also shown buried in ice in 1379: 4.5 Degrees. Knit caps have only been used a few times in xkcd, most prominently on Knit Cap Girl in 1350: Lorenz, see her section for more details.
19500 BCE But the world is about to warm up.
By this time, humans have already spread across Africa, Eurasia, and Australia.
They’ve created painting, pottery, rope, and bows and arrows, but haven’t developed writing or farming.
19000 BCE Changes in the Earth’s orbit mean that more sunlight reaches the polar ice… Last North American Pokémon go extinct — as prehistoric Megan states, this is not a real fact. Pokémon are still thriving throughout the entire world (see 1705: Pokémon Go), and are most commonly found near regions of dense human habitation.
[A line chart with a labeled Y-axis "Summer sun W/m2 at 60°N" with three labeled ticks ranging from 450-550. The curve starts up and then goes down five times and up four times ending down. There is one plateau towards the end compared to the rest of the curve where the ups and downs are quite alike.]
18500 BCE [A map of the world. At the top is a light gray area covering North America, Greenland and northern Europe and most of the northern part of Russia. A similar gray area covers Antarctica. The gray areas are labeled as ice.]
18000 BCE …And the ice sheets start to melt.
17500 BCE Temperatures have been creeping upward, but around this point, CO2 levels start to climb…
17000 BCE …And then the warming speeds up.
16500 BCE [Cueball is standing with a spear just the right of the graph talking to a rabbit.]
Cueball: Still pretty cold.
16000 BCE [Megan points to the graph to the right of her and between her and Ponytail standing on the other side. Mean is the first drawing on the left side of the dotted curve, which has hardly moved since the beginning, only to just on the other side of 4°C.]
[In the right part of the chart is an explanation of the data. Below the first two lines there are four drawings each showing possible temperature swings in reality compared to the smoothed data that represents the dotted curve of the entire chart. The dotted curve is shown in all four drawings and a thin line is shown running along it but with much more fluctuation left and right on the first two, a large spike right on the third and a large bump way right on the fourth. Above these there are two labels. The first labels is inside a bracket that covers the first three, and the last label is for the last drawing. Below is a list of sources.]
Limits of this data:
Short warming or cooling spikes might be “smoothed out” by these reconstructions but only if they’re small or brief enough.
Possible Unlikely
Reconstructions are from Shakun (2012) and Marcott (2013), scaled to Annan + Hargreaves (2013) estimate for the last glacial period.
15500 BCE In what is now France, humans paint murals on the walls of the Lascaux caves
[Hairy paints three animals, two with horns, and two humans, Cueball holding hand with Hairy who has a spear. On the other side of the central line Megan writes three letters, the last of which is reversed:] NIИ


15000 BCE Ice sheets around Alaska shrink, exposing a land bridge between Asia and North America
[From around the bottom if this section and down to 11500 BCE the dotted curve moved steadily to the right towards warmed temperature peaking close to -1.5°C. Before this the temperature had not moved much away from that at the start.]
14500 BCE Cueball: Cool.
14000 BCE The edge of the ice withdraws from New York City and retreats North.
[A large glacier front speaks in a speech bubble with an arrow pointing at it. Behind is there are four peaks in the horizon and in front of it three small melting pools and some rocks on the ground.]
Glacier: That’s it1 I’m moving to Canada!
13500 BCE Humans domesticate dogs
(Date uncertain, may be much earlier)
[Megan and Cueball is watching a wolf looking at them.]
Megan: Okay, you can live in our homes and we’ll feed you, but we’ll still get mad f you poop on the floor.
Wolf: Deal.
Cueball: And we get to breed you to be tiny and dress you in little costumes
Wolf: …Wait.
13000 BCE Woolly Rhino goes extinct
Oregon is scoured by huge floods as glacial dams burst and lakes of meltwater flow to the sea
12500 BCE Ice sheets withdraw from Chicago
12000 BCE Humans settle Abu Hureyra in Syria
11500 BCE [An arrow on the left side of the dotted curve is pointing down along the dotted curve and to the left indicate temperature is declining again, meaning the dotted curve now moves left to colder temperatures. This only continues until 10500 BCE. It is only the second time something is noted on the left side after Megan at 16000 BCE]
Temperatures start to decline, mainly in the Northern hemisphere
This may be caused by changes in ocean circulation due to the floods of cold fresh meltwater flowing into the Atlantic as the North American ice sheet melts.
This cooler period is called the Younger Dryas


11000 BCE [This is the first text to the left of the dotted curve:]
Humans reach Argentina
10500 BCE [An arrow pointing down along the right side of the dotted curve and to the right indicate temperature is increasing again, meaning the dotted curve now moves right to hotter temperatures. This continues until 8000 BCE where it levels out just above 0°C.]
Warming resumes
Human settlements at Jericho
10000 BCE First development of farming
9500 BCE Saber-toothed cat goes extinct
Horses disappear from North America
9000 BCE Last North American Pokémon go extinct
[Cueball with a speak and Megan is looking up at this last “fact”.]
Megan: That is not a real fact.
Temperatures reach modern levels
Rising seas cut off the land bridge between North America and Asia
Cattle domesticated
8500 BCE Ice sheets retreat across the Canadian border
Temperatures start to level out slightly above 1961-1990 levels
8000 BCE [The above sentence breaks over the 8000 BCE line. From here a maximum in temperature on the chart is reached at 0.5°C which will not be overtaken until 2000 CE. It stays almost constant here until 5000 BCE where a slight cooling begins.]


7500 BCE This warm, stable period is called the Holocene Climate Optimum
Jiahu settled in China
7000 BCE Final collapse of the North American ice sheet leads to rapid 2-4m sea level rise…
[A small arrow points down and left to the right of the dotted curve. There is a small decrease in temperature but it is very small and would have been missed without the arrow and label.]
…And a period of cooling in the Northern hemisphere
6500 BCE As seas rise to near their modern levels, Britain is cut off from mainland Europe
6000 BCE Humans develop copper metalworking
5500 BCE Massive volcanic eruption in Oregon creates crater lake
Gold metalworking
5000 BCE Invention of the wheel
[To the right of the dotted curve is an arrow pointing down and slightly left. From here temperature decreases very slowly but steadily from 0.5°C until 1000 BCE where a stable plateau is reached around 0°C.]
Earth begins to cool slowly mainly due to regular cycles in its orbit
4500 BCE Proto-Indo-European language develops
[To the right of the curve Ponytail holds up a hand towards Cueball.]
Ponytail: Let’s make out language heavily inflected, so future students have to memorize a zillion verb endings!
Cueball: Okay!
Ponytail refers to 1709: Inflection.
Permanent settlements in the fertile crescent
4000 BCE Horses domesticated
Minoan culture arises on Crete
3500 BCE Egyptian mummification
Rise of the Indus Valley civilization
Invention of writing in Sumer “prehistory” ends, “history” begins
Earliest human whose name we know (Pharaoh Iry-Hor in Egypt)
3000 BCE Three Sovereigns and Five Emperors period in China
Gilgamesh
Imhotep
Mayan culture emerges
Great Pyramid constructed
2500 BCE Corded Ware culture in Europe
[To the left of the curve two rock musicians with long hair and electrical guitars are standing on either side of a small gate made of three slabs of stone, one on top of the other two standing stones.]
Stonehenge completed
2250 The drawing is a reference to the 1984 movie "This is Spinal Tap" (A documentary/parody featuring the fake metal band "Spinal Tap", http://www.imdb.com/title/tt0088258/), the musicians order a Stone Henge prop for the stage, which turns out to be too small (https://www.youtube.com/watch?v=qAXzzHM8zLw)
Chariots developed
2000 BCE Alphabetic writing developed in Egypt
Last mammoths on a tiny Siberian island go extinct
Minoan eruption
1500 BCE Iron smelting
Olmec civilization develops in Central America
[A Trojan horse with two Cueball-like guys in front and a third standing on its back. Its back is at three Cueball’s height and its head rises to the level of the Cueball on its back. It stands on a platform with four wheel on the visible side. There is text on the horse]
Setting of the Iliad and the Odyssey
Text on horse: Not a trap
Invasion of the Sea peoples*
* A real thing
Polynesians explore the Pacific Ocean
1000 BCE [From 1000 BBC to 1000 CE the temperature is stable and very close to 0°C.]
Solomon
Iliad and Odyssey composed
Rise of Greek city-states
Neo-Assyrian empire
First Olympics
Zapotec writing in modern Mexico
Confucius
500 BCE movie 300, but regular speed and with more clothing
Buddha
Nazca Lines
Alexander the Great
Mayan hieroglyphics
Ashoka the Great
Paper invented
Asterix
Teotihuacán metropolis
Julius Caesar
1 BCE
1 CE
[At the year 0, there is instead two numbers for each of the two scales before (1 BCE) and after Christ (1 CE)]
Roman Empire
Jesus
[To the left and erupting volcano.]
Pompeii
Three Kingdoms period
Gupta empire
Various groups take turns sacking Rome
Attila the Hun
500 CE Muhammad
Tang Dynasty
[An arrow to the right of the dotted curve pointing down, takes a swing far out from the curve and then bends back again. The text label next to it breaks into the next 500 period. The dotted curve stays stable at 0°C along this arrow.]
Medieval warm period in Europe and some northern regions (too regional to affect the global average much)
Leif Eriksson
1000 CE [The dotted curve moves to the left towards lower temperature reaching a minimum around 1650 of about -0.6°C at the Little Ice Age.]
[To the left a drawing of a compass with needle pointing the black end towards north west. There are labels for the four main directions (N, S, E, W) and a label next to it:]
Magnetic compass navigation
Ghengis Khan
Zheng He’s fleet explores Asia and Africa
Aztec Alliance
Printing press
Columbus
1500 CE European Renaissance
Shakespeare
1600 Newton
[To the right of the dotted curve there is an arrow pointing down that makes a swing in towards the curve and then back out again. At -0.6°C this is the coldest it has been since 9500 BCE. It is labeled:]
”Little Ice Age”
1700 Steam engines
Unites States Independence
1800 Industrial Revolution
Telegraphs
[After this the dotted curve becomes solid.]
1900 Airplanes
World Wars
[The solid line takes a step to the right close to 0°C. Over the rest of the 1900s it moves closer to 0°C crossing it before 2000 where it almost reaches the maximum temperature of 0.5 °C from earlier in 8000 BCE.]
Fossil fuel CO2 emissions start rapidly increasing
Nuclear weapons
Internet


2000 Northwest Passage opens
[From here to present day the solid line increases rapidly and in 2016 present day is almost reaches 1°C, with about 0.8°C.]
2016 Present day
[From here the curve once again becomes dotted as this is the future. After one dot it splits in two and after the first two dots another split between them occurs forming three possible future dotted curves.]
The first curve bending down before the others, and thus to the right of the other two reaches about 1.2°C and then goes straight down and stops at the 2100 line. An arrow points to it from the left and a label is written partly before and the rest after the 2100 line to the left of the curve:]
Best-case scenario assuming immediate massive action to limit emissions
2100 [The middle curve bends a little down after reaching 1.3°C and then continues this path reaching 2°C in 2100. An arrow point from below to it and a label is written below the curve and below 2100 line:]
Optimistic scenario
[The last line continues along the path from the last 16 years of the solid line reaching 4.2°C at 2100, almost as far on the other side of 0°C in 150 years as it took 14000 years to move from the other side from the start of the chart. Another arrow point to this from below with a label below the curve and below 2100 line:]
Current Path

Sources

The image attributes climate data sources as "Shakun et al. (2012), Marcott et al. (2013), Annan and Hargreaves (2013), HadCRUT4, IPCC":

Transcript

Note there are several spelling errors in the comic, so please do only correct spelling errors that are not part of the comic! See more in the trivia section.

[A large heading, followed by a sub-caption. Below that two lines with a statement in between:]
A timeline of Earth’s average temperature
since the last ice age glaciation
When people say “The climate has changed before,” these are the kinds of changes they’re talking about.
[A very long chart below the headings above is headed with a label for the scale of the X-axis above the chart. Below that a sub-caption. To the left an arrow down to the top of the chart pointing to the dotted curves starting point (at -4.3°C) with a label above the arrow. And arrow pointing left to the left of the center and another pointing right to the right of the center has labels. Below these is the temperature scale of the X-axis, with 9 ticks between the borders each with a label ranging from -4 to +4°C, but with another step in each direction not labeled towards to axis so the chart covers -5 to +5°C.]
Temperature
Compared to the 1961-1990 average
Start
Colder
Warmer
-4°C -3°C -2°C -1°C 0°C +1°C +2°C +3°C +4°C
[To the right of the chart is a gray text standing on the side down along the outer boarder of the chart with the sources for the chart:]
Source: Shakun et. al. (2012) , Marcott et. al. (2013), Annan and Hargreaves (2013) , HadCRUT4, IPCC
[The chart is split in 10 columns by the temperature scale and the borders. The two central columns are white, and then from there to the left the background becomes a faded color that changes from light blue to blue at the edge in four steps. Similarly to the right the color changes from light red to red. To the left there is a time scale taking 500 years leaps from 20,000 BCE all the way to year 1, where there are two years, one for BBC and one for CE. The 500 year leaps continue until 1500 CE and from there the steps are down to 100 years until 2100 with also present day 2016 labeled. After 1500 the CE is omitted. The labels stop there, but there is space below covering down to 2200 CE. There is clearly visible division line across the chart on the level of each of the 500 step, and fainter lines for each of the 100 steps all the way even though only the last 5 of these 100 steps are labeled. There is a similar clear line at 2016. Below each step on the Y-axis is noted, and then any text starting before the next step is noted below indented. If there are extra image belonging to text this is indented once more. The graph that the whole chart is about is a dotted line that begins at the “start” point mentioned above at -4.3°C and then begins to go straight down. It will change left and right all the way down. To being with all text and most drawings are to right of the dotted curve. Whenever something is to the left it will be noted. When it says to the left above something, and then nothing over the next, then the next will be to the right. Only at the very bottom are there more entries to the left than right. ]
20000 BCE
[An arrow goes from the dotted line to the central line at 0°C. In the middle of the line there is a temperature label:]
4.3°C
At the start of our timeline, 22,000 years ago, Earth is 4°C colder than during the late 20th century.
Boston is buried under almost a mile of ice, and the glaciers reach as far south as New York City.
[The Statue of Liberty is shown in front of a glacier front. A very tiny Cueball is on top of the glacier. The drawing is labeled and so is also the glacier.]
New York
Ice
[A guy with a white knit cap is seen walking in a snowy landscape leaving black footprints behind him. He walks through the white central part of the chart.]
[The skyline of Boston is shown with two clear buildings among all the other. Above it is a line and in between this area has been filled with thin lines. The drawing is labeled and so is this area. Also the skyline has an arrow pointing at it with a label:]
Boston
Ice
Modern skyline
19500 BCE
But the world is about to warm up.
By this time, humans have already spread across Africa, Eurasia, and Australia.
They’ve created painting, pottery, rope, and bows and arrows, but haven’t developed writing or farming.
19000 BCE
Changes in the Earth’s orbit mean that more sunlight reaches the polar ice…
[A line chart with a labeled Y-axis with three labeled ticks. The curve starts up and then goes down five times and up four times ending down. There is one plateau towards the end compared to the rest of the curve where the ups and downs are quite alike.]
Summer sun W/m2 at 60°N
550
500
450
18500 BCE
[A map of the world. At the top is a light gray area covering North America, Greenland and northern Europe and most of the northern part of Russia. A similar gray area covers Antarctica. There are two labels in the gray area above and one in the gray area below:]
Ice Ice
Ice
18000 BCE
…And the ice sheets start to melt.
17500 BCE
Temperatures have been creeping upward, but around this point, CO2 levels start to climb…
17000 BCE
…And then the warming speeds up.
16500 BCE
[Cueball is standing with a spear just the right of the graph talking to a rabbit.]
Cueball: Still pretty cold.
16000 BCE
[Megan points to the graph to the right of her and between her and Ponytail standing on the other side. Mean is the first drawing on the left side of the dotted curve, which has hardly moved since the beginning, only to just on the other side of 4°C.]
[In the right part of the chart is an explanation of the data. Below the first two lines there are four drawings each showing possible temperature swings in reality compared to the smoothed data that represents the dotted curve of the entire chart. The dotted curve is shown in all four drawings and a thin line is shown running along it but with much more fluctuation left and right on the first two, a large spike right on the third and a large bump way right on the fourth. Above these there are two labels. The first labels is inside a bracket that covers the first three, and the last label is for the last drawing. Below is a list of sources.]
Limits of this data:
Short warming or cooling spikes might be “smoothed out” by these reconstructions but only if they’re small or brief enough.
Possible Unlikely
Reconstructions are from Shakun (2012) and Marcott (2013), scaled to Annan + Hargreaves (2013) estimate for the last glacial period.
15500 BCE
In what is now France, humans paint murals on the walls of the Lascaux caves
[Hairy paints three animals, two with horns, and two humans, Cueball holding hand with Hairy who has a spear. On the other side of the central line Megan writes three letters, the last of which is reversed.]
NIИ
15000 BCE
Ice sheets around Alaska shrink, exposing a land bridge between Asia and North America
[From around the bottom if this section and down to 11500 BCE the dotted curve moved steadily to the right towards warmed temperature peaking close to -1.5°C. Before this the temperature had not moved much away from that at the start.]
14500 BCE
[Cueball walks right looking back at the graph behind him. Megan walks in front of him pointing further right.]
Cueball: Cool.
14000 BCE
The edge of the ice withdraws from New York City and retreats North.
[A large glacier front speaks in a speech bubble with an arrow pointing at it. Behind is there are four peaks in the horizon and in front of it three small melting pools and some rocks on the ground.]
Glacier: That’s it1 I’m moving to Canada!
13500 BCE
Humans domesticate dogs
(Date uncertain, may be much earlier)
[Megan and Cueball is watching a wolf looking at them.]
Megan: Okay, you can live in our homes and we’ll feed you, but we’ll still get mad f you poop on the floor.
Wolf: Deal.
Cueball: And we get to breed you to be tiny and dress you in little costumes.
Wolf: …Wait.
13000 BCE
[Randall did not use the normal spelling for Woolly Rhino, but this is an accepted alternative spelling:]
Wooly Rhino goes extinct
Oregon is scoured by huge floods as glacial dams burst and lakes of meltwater flow to the sea
12500 BCE
Ice sheets withdraw from Chicago
12000 BCE
Humans settle Abu Hureyra in Syria
11500 BCE
[An arrow on the left side of the dotted curve is pointing down along the dotted curve and to the left indicate temperature is declining again, meaning the dotted curve now moves left to colder temperatures. This only continues until 10500 BCE. It is only the second time something is noted on the left side after Megan at 16000 BCE]
Temperatures start to decline, mainly in the Northern hemisphere
This may be caused by changes in ocean circulation due to the floods of cold fresh meltwater flowing into the Atlantic as the North American ice sheet melts.
This cooler period is called the Younger Dryas
11000 BCE
[This is the first text to the left of the dotted curve:]
Humans reach Argentina
10500 BCE
[An arrow pointing down along the right side of the dotted curve and to the right indicate temperature is increasing again, meaning the dotted curve now moves right to hotter temperatures. This continues until 8000 BCE where it levels out just above 0°C.]
Warming resumes
Human settlements at Jericho
10000 BCE
First development of farming
9500 BCE
Saber-toothed cat goes extinct
[To the left:]
Horses disappear from North America
9000 BCE
[To the left, Randall spelled Pokémon wrong:]
Last North American Pokemon go extinct
[Cueball with a speak and Megan is looking up at this last “fact”.]
Megan: That is not a real fact.
Temperatures reach modern levels
Rising seas cut off the land bridge between North America and Asia
Cattle domesticated
8500 BCE
Ice sheets retreat across the Canadian border
Temperatures start to level out slightly above 1961-1990 levels
8000 BCE
[The above sentence breaks over the 8000 BCE line. From here a maximum in temperature on the chart is reached at 0.5°C which will not be overtaken until 2000 CE. It stays almost constant here until 5000 BCE where a slight cooling begins.]
7500 BCE
[To the left:]
This warm, stable period is called the Holocene Climate Optimum
[To the left:]
Jiahu settled in China
7000 BCE
Final collapse of the North American ice sheet leads to rapid 2-4m sea level rise…
[A small arrow points down and left to the right of the dotted curve. There is a small decrease in temperature but it is very small and would have been missed without the arrow and label.]
…And a period of cooling in the Northern hemisphere
6500 BCE
[To the left:]
As seas rise to near their modern levels, Britain is cut off from mainland Europe
6000 BCE
Humans develop copper metalworking
5500 BCE
[To the left:]
Massive volcanic eruption in Oregon creates crater lake
Gold metalworking
5000 BCE
[To the left:]
Invention of the wheel
[To the left. To the right of the dotted curve is an arrow pointing down and slightly left. From here temperature decreases very slowly but steadily from 0.5°C until 1000 BCE where a stable plateau is reached around 0°C.]
Earth begins to cool slowly mainly due to regular cycles in its orbit
4500 BCE
[To the left:]
Proto-Indo-European language develops
[To the right of the curve Ponytail holds up a hand towards Cueball.]
Ponytail: Let’s make out language heavily inflected, so future students have to memorize a zillion verb endings!
Cueball: Okay!
[To the left:]
Permanent settlements in the fertile crescent
4000 BCE
Horses domesticated
[To the left:]
Minoan culture arises on Crete
3500 BCE
Egyptian mummification
Rise of the Indus Valley civilization
[To the left:]
Invention of writing in Sumer “prehistory” ends, “history” begins
Earliest human whose name we know
(Pharaoh Iry-Hor in Egypt)
3000 BCE
Three Sovereigns and five emperors period in China
Gilgamesh
[To the left:]
Imhotep
Mayan culture emerges
[To the left:]
Great Pyramid constructed
2500 BCE
Corded Ware culture in Europe
[To the left of the curve two rock musicians with long hair and electrical guitars are standing on either side of a small gate made of three slabs of stone, one on top of the other two standing stones.]
Stonehenge completed
Chariots developed
2000 BCE
[To the left:]
Alphabetic writing developed in Egypt
Last mammoths on a tiny Siberian island go extinct
[To the left:]
Minoan eruption
1500 BCE
[To the left:]
Iron smelting
Olmec civilization develops in Central America
[A Trojan horse with two Cueball-like guys in front and a third standing on its back. Its back is at three Cueball’s height and its head rises to the level of the Cueball on its back. It stands on a platform with four wheel on the visible side. There is text on the horse]
Setting of the Iliad and the Odyssey
Text on horse: Not a trap
[To the left:]
Invasion of the Sea peoples*
* A real thing
Polynesians explore the Pacific Ocean
1000 BCE
[From 1000 BBC to 1000 CE the temperature is stable and very close to 0°C.]
[To the left:]
Solomon
[Randall spelled Iliad wrongly this time:]
Illiad and Odyssey composed
[To the left:]
Rise of Greek city-states
Neo-Assyrian empire
[To the left:]
First Olympics
Zapotec writing in modern Mexico
[To the left:]
Confucius
500 BCE
[To the left:]
The stuff in the 300 (film)|movie 300, but regular speed and with more clothing
Buddha
Nazca Lines
[To the left:]
Alexander the Great
[To the left:]
Mayan hieroglyphics
Ashoka the Great
[To the left:]
Paper invented
[To the left:]
Asterix
Teotihuacán metropolis
[To the left:]
Julius Caesar
[At the year 0, there is instead two numbers for each of the two scales before and after Christ:]
1 BCE
1 CE
[To the left:]
Roman Empire
Jesus
[To the left and erupting volcano.]
Pompeii
Three Kingdoms period
[To the left:]
Gupta empire
[To the left:]
Various groups take turns sacking Rome
[Randall spelled Attila wrong:]
Atilla the Hun
500 CE
Muhammad
[To the left:]
Tang Dynasty
[An arrow to the right of the dotted curve pointing down, takes a swing far out from the curve and then bends back again. The text label next to it breaks into the next 500 period. The dotted curve stays stable at 0°C along this arrow.]
Medieval warm period in Europe and some northern regions (too regional to affect the global average much)
[To the left:]
Leif Eriksson
1000 CE
[The dotted curve moves to the left towards lower temperature reaching a minimum around 1650 of about -0.6°C at the Little Ice Age.]
[To the left a drawing of a compass with needle pointing the black end towards north west. There are labels for the four main directions and a label next to it:]
N
E W
S
Magnetic compass navigation
[To the left:]
Ghengis Khan
Zheng He’s fleet explores Asia and Africa
[To the left:]
Aztec Alliance
[To the left:]
Printing press
[To the left:]
Columbus
1500 CE
European Renaissance
[To the left:]
Shakespeare
1600
[To the left:]
Newton
[To the right of the dotted curve there is an arrow pointing down that makes a swing in towards the curve and then back out again. At -0.6°C this is the coldest it has been since 9500 BCE. It is labeled:]
”Little Ice Age”
1700
Steam engines
[To the left:]
Unites States Independence
1800
Industrial Revolution
[To the left:]
Telegraphs
[After this the dotted curve becomes solid.]
1900
[To the left, and on the line for 1900:]
Airplanes
[To the left:]
World Wars
[The solid line takes a step to the right close to 0°C. Over the rest of the 1900s it moves closer to 0°C crossing it before 2000 where it almost reaches the maximum temperature of 0.5 °C from earlier in 8000 BCE.]
Fossil fuel CO2 emissions start rapidly increasing
[To the left:]
Nuclear weapons
[To the left:]
Internet
2000
Northwest Passage opens
[From here to present day the solid line increases rapidly and in 2016 present day is almost reaches 1°C, with about 0.8°C.]
2016
[To the left on the line for 2016:]
Present day
[From here the curve once again becomes dotted as this is the future. After one dot it splits in two and after the first two dots another split between them occurs forming three possible future dotted curves. The first curve bending down before the others, and thus to the right of the other two reaches about 1.2°C and then goes straight down and stops at the 2100 line. An arrow points to it from the left and a label is written patly before and the rest after the 2100 line to the left of the curve:]
Best-case scenario assuming immediate massive action to limit emissions
2100
[The middle curve bends a little down after reaching 1.3°C and then continues this path reaching 2°C in 2100. An arrow point from below to it and a label is written below the curve and below 2100 line:]
Optimistic scenario
[The last line continues along the path from the last 16 years of the solid line reaching 4.2°C at 2100, almost as far on the other side of 0°C in 150 years as it took 14000 years to move from the other side from the start of the chart. Another arrow point to this from below with a label below the curve and below 2100 line:]
Current Path

Trivia

  • The timeline starts at 20000BCE (22,000 years ago) and ends near 2200CE, thus covering 22,200 years.
  • There are several spelling mistakes.
    • Most obvious is the second time Randall wrote the word "Iliad," because he just spelled it correctly at 1500 BCE and then spelled it Illiad at 1000 BCE with two "L"s.
    • Attila the Hun becomes Atilla the Hun with only one t.
    • Pokémon is spelled Pokemon, but then again that is not so strange for Randall (see 1647: Diacritics).
    • Note that the fact that Woolly rhinoceros becomes Wooly rhino with only one l is not a spelling mistake but an alternative spelling of the word.


comment.png add a comment! ⋅ comment.png add a topic (use sparingly)! ⋅ Icons-mini-action refresh blue.gif refresh comments!

Discussion

Troll.png As this is a controversial topic, there may be several denialist trolls lurking below. Beware of feeding them.

Well, never mind then. Oh well. -- JayRulesXKCD (talk) 1:02, 12 September 2016

I acknowledge that the picture is WAY too long, so I added a "skip to explanation" bar, to speed things up. --JayRulesXKCD (talk) 17:32, 12 September 2016 (UTC)
Thank you Run, you clever boy (talk)

Is it just me or does the picture not render all the way down in full resolution on firefox? I found it worked on Chrome and explorer... And Wauw, just after I had created the new Category:Climate change... Was also just watched a QandA program yesterday where Brian Cox tried to convince some Australian politician about global warming, but the other one just cried conspiracy... Will take some time to make this one complete I guess? Great ;-) --Kynde (talk) 17:53, 12 September 2016 (UTC)

That's the thing with this kind of stuff. It takes a LONG time to make it just right. --JayRulesXKCD (talk) 19:08, 12 September 2016 (UTC)

Please delete the ridiculous trivia

  • The colors used to represent temperature vary from blue (the perceived hue of a black body at 20000K) to pale red (perceived at 2200K).

108.162.221.139 19:44, 12 September 2016 (UTC)

Of course you can pretty much ignore the part of the diagram that is in dotted line, you can't rely on that data. 108.162.246.119 20:40, 12 September 2016 (UTC)

Note that even if we ignore the extrapolated future, the warming in the past century is already a vastly more abrupt climate shift than anything that happened in the preceding 219 centuries. - Frankie (talk) 21:15, 12 September 2016 (UTC)
Actually we don't know what the shifts were on that scale in the past. The dotted line before modern measurement is a very limited estimate. We have no idea what the year to year changes were in the past, at best we can work out an average. I am reminded of a house mouse(life span of about 1 year) looking at the leaves fall from the tress and saying "Surely this is the end of the world". 108.162.246.119 14:44, 13 September 2016 (UTC)
Randall explicitly addresses your specious complaint at 15900 BCE. Year-to-year fluctuations are not the same as the current century-long surge. Either show scientific evidence or go away, Mr Troll from Seattle Cloudflare. - Frankie (talk) 16:11, 13 September 2016 (UTC)
I should have known better to enter into a religious debate on the internet. 108.162.246.119 00:17, 14 September 2016 (UTC)
No it is not that which is the problem, but that you try to disqualify the data without even bothering to look through them. Aa mentioned Randall tries to let us know that such a high fluctuation as we have in these last 100 years would not be hidden in the old data. As mentioned by Fankie this is explained between 16000 and 15500 BCE... --Kynde (talk) 14:30, 14 September 2016 (UTC)
I refuse to debate a matter of faith with you. Note that 15500-16000 is 500 years, perhaps when we have 500 years of accurate temperature measurements we will know more. 108.162.246.119 03:54, 15 September 2016 (UTC)
I'm not surprised that you can't even read a chart. 16000-15500 BCE is where the explanation is placed on the chart. The fluctuations he shows that would not register are small fluctuations over a decade or two. A fluctuation of a century would "unlikely" be smoothed out. The examples are even drawn to scale... 3rd grade level stuff here. 108.162.221.145 17:28, 16 September 2016 (UTC)
Why even bring your faith into this? 108.162.212.92 16:29, 15 September 2016 (UTC)
I call Troll. Talking about the significance of where the subchart/Legend/footnote lies? Like what years it's next to actually has any significance? Either he's too dim to actually look, or he's trolling. The standard recommendation is "Don't feed the trolls". :) - NiceGuy1 108.162.218.118 02:55, 16 September 2016 (UTC) I finally signed up! This comment is mine. (Heh, seems I was right, looks like the troll stopped after I called him out) :) NiceGuy1 (talk) 11:03, 9 June 2017 (UTC)
Frankie, funny how the nonaveraged plots [and even the averaged plot] linked to below invalidates Randall's plot, "Hence the comparison is not comparing like with like and is scientifically invalid." The temperature rate between 1859 (coincident with America's discovery of petroleum and the Carrington Event) and today does not exceed that within the past 2,000, 20,000, or 100,000s of years. The present surge (the tip of the "hockey stick") concerns not 100 years but almost 40 years (36 years in Randall's plot) which does not successfully meet the three fluctuation disclaimers. As mentioned in the Wikimedia discussion the temperature resolution is about 300 years; therefore it should take another 150 years to see whether this slope corrects itself. Lysdexia (talk) 13:04, 5 January 2019 (UTC)
Have you read the referenced papers? Well you fit well with the people he refers to between the two lines at the top. ;-) We are heading for troublesome times :-( 164: Playing Devil's Advocate to Win... --Kynde (talk) 21:22, 12 September 2016 (UTC)
  • the use unqualified of the words "still many people" is exactly the kind of weasely nonsense that this comic is designed to refute. there are "still many people" who claim the earth is flat, that they have been abducted by aliens, or that the MMR jab made their children autistic. those people are deluded or insincere. the difference with deniers of climate change is that there are in their ranks scientists who are clear-sighted but who have decided that funding at any price is better than none. this site should be better than that. --141.101.98.84
You're absolutely right, the ranks of climate deniers do indeed include a few scientists willing to sell their voices to the highest bidder (e.g. http://www.polluterwatch.com/heartland-institute ). But is that what you meant to say? - Frankie (talk) 11:50, 13 September 2016 (UTC)
that the wording be changed to reflect that. --141.101.98.84 11:59, 13 September 2016 (UTC)

For a large post like this, it's a wonder that we can all keep up and edit something like this all at once. Wow. --JayRulesXKCD (talk) 11:56, 13 September 2016 (UTC)

Also, anyone else notice that this was a top trending post on Facebook last night? I don't know if I could call it a milestone but it's still pretty cool. And WE edited it! :D --JayRulesXKCD (talk) 12:06, 13 September 2016 (UTC)
Very interesting, so it was explain xkcd and not xkcd that where the top trending post? Could you post a link to where you found this out? --Kynde (talk) 20:15, 13 September 2016 (UTC)
I can see you are right from the fact that Randall has chosen to postpone his next comic in order to keep this one on the front page for all the new visitors as has now been noted in the explanation and in the trivia section. --Kynde (talk) 14:30, 14 September 2016 (UTC)

Maybe someone should add the fact that the transcript may be a reference to oxidation?Transuranium (talk) 19:21, 13 September 2016 (UTC)Transuranium

I think you mean the "title text" not the transcript? And that you refer to the recent comic 1693: Oxidation which is indeed referened in the title text, then that has been written at the bottom of the main explanation and has been there already since the 12th edit less than 1½ hour after the comic came out... --Kynde (talk) 20:02, 13 September 2016 (UTC)

Is nobody else having a problem seeing the comic? Both here and on XKCD I get an "Image not found" icon, a blue question mark. I thought maybe this was an interactive comic that doesn't work on my iPad (like that garden thing, though that did nothing on my computer either). If I tap it on XKCD nothing happens, here it leads to the picture's Wiki page - also with the question mark - which says it's a PNG, which I know this iPad can show. It's 11pm EST, maybe night maintenance on XKCD? Or the file got renamed without updating the sites? - NiceGuy1 162.158.126.227 03:12, 14 September 2016 (UTC) I finally signed up! This comment is mine. NiceGuy1 (talk) 11:03, 9 June 2017 (UTC)

I had trouble seeing it on my own PC using Firefox but not the other browsers I have. See my early comment above. I guess the file is too big for your iPad as it is a very huge file. I tried to download it but it failed. --Kynde (talk) 14:07, 14 September 2016 (UTC)
It's weird that I got what is clearly an "Image not found" icon, though. Maybe my 1st Gen iPad's Safari saw the file, decided "No way I'm loading that!"(or "that size can't be right", LOL!) and chose to show the error icon instead. When I force the issue, by going directly to the image URL listed on XKCD, the first time Safari crashed rather than load the image (but it crashes on a regular basis, so that didn't deter me), the second time it crashed, the third time it actually loaded, and I was able to see it. After seeing mentions here of spelling errors (though I have to disagree on "Pokemon", generally only people connected to the show bother with the accent. Like how I'm the only one who spells Hallowe'en correctly, with the apostrophe), I thought maybe the comic was taken down to correct it, but guess not. LOL! - NiceGuy1 108.162.218.239 20:54, 14 September 2016 (UTC) So's this! NiceGuy1 (talk) 11:03, 9 June 2017 (UTC)

I feel that the missing bottom axis is a usability problem, so I fixed it. See it here. Hananc (talk) 10:42, 14 September 2016 (UTC)

Nice but I'm sure it was on purpose to indicate that time continues down,as well as a possible even worse temperature change. As shown in the previous global warming comic 1379 Earth has been 8 degree hotter than now... And apart from the last small segment (albeit a very important one) you either remember that white is normal and bluer is colder redder is warmer or else you cannot use the chart in between the top and bottom, and since this is the longest xkcd comic so far it would be a shame. :-) --Kynde (talk) 14:07, 14 September 2016 (UTC)

Okay, now that I've managed to SEE the damn thing, I have a question. There's no mention of why this is using "BCE" and "CE" instead of the standard "BC" and "AD", never mind what these stand for (thinking and thinking about it, my guess is "Before Christ Era" and "Christ Era"). This is the kind of thing that should be mentioned on ExplainXKCD, LOL! Fun fact: when I searched this page for "BCE", to confirm it wasn't explained, I got "Over 100 matches". :) Anyway, I figure maybe those are currently accepted scientific terminology, especially since "AD" is Latin, unlike "BC", but the average person still uses BC and AD. In fact, I think this is the first time I've ever seen BCE and CE (unless it's been on XKCD before and I just dismissed it as a typo or something. This time there are WAY too many for it to be a mistake every time, including here in the explanation!) - NiceGuy1108.162.218.239 21:20, 14 September 2016 (UTC) I finally signed up! This comment is mine. NiceGuy1 (talk) 11:03, 9 June 2017 (UTC)

It's "Before Common Era" and "Common Era", an alternative to BC/AD. Pretty common alternative, though I don't know why off-hand - probably to remove the religious connotations of "Christ" and "Year of our Lord". --108.162.215.236 23:23, 14 September 2016 (UTC)
Because they're the standards in the scientific community. The guy above assumed his way is standard, but that's inaccurate. 108.162.212.92 00:26, 15 September 2016 (UTC)
I assume nothing. My statements are completely accurate. I OBSERVE it is the standard, the only standard anybody (else) seems to use. BC/AD is the "standard" because it is standard practice to use it. For good reason, since I would estimate just about everybody knows what it means, while I am sure I am in the majority in having never heard BCE/CE. It is also not "my" way, I made no choice here, it is the established convention, it is the way accepted and adopted by society. While I would normally be more inclined towards terminology devoid of religion (as seems to be the point here, now that someone kindly clarified these acronyms for me), I feel this would be a losing fight, one it would be foolish to attempt, the classic terminology is too ingrained in society. Sorry. - NiceGuy1 108.162.218.118 02:44, 16 September 2016 (UTC) Also mine! NiceGuy1 (talk) 11:03, 9 June 2017 (UTC)
For the convenience of archeologists working in the Middle East. Wwoods (talk) 01:16, 15 September 2016 (UTC)
Thank you! Yes, it sounds to me like the point would be to remove the religious aspect. Personally, I don't really mind the religious terminology, I just see it as historical, keeping a record of where the names and numbering came from. - NiceGuy1 108.162.218.118 02:44, 16 September 2016 (UTC) Also mine! NiceGuy1 (talk) 11:03, 9 June 2017 (UTC)

What this comic doesn't show is what kind of changes occurred in the previous interglacial period as opposed to the current one. Since the current one is not yet over there could still be a stage of an interglacial with rapid temperature rise which we are only now reaching, but has happened in previous interglacial periods. 108.162.219.54 02:32, 15 September 2016 (UTC)

Check out this 400k year comparison of temperature variations from two ice core projects in Antarctica, Lake Vostok and EPICA. https://commons.wikimedia.org/wiki/File:Ice_Age_Temperature.png (Note that Randall's timeline matches up pretty well with the last 20k years on the far right of the graph) 162.158.69.98 13:23, 16 September 2016 (UTC)

I think this would be first time where I see global thermonuclear war described as "best case scenario". There was and still is lot of discussion about how much is current warming caused by humans, but that's not important. Important question is "can we stop it?" and the answer is "not without literally billions of dead" (and even that might not suffice). Any money currently used for most plans to reduce CO2 (which usually fails to reduce CO2, not speaking about global warming, but succeed in their main goal, which is moving the money into pockets of their proponents) would be better spent on ADAPTING to the change. Only plans for reducing CO2 actually worth doing are the ones related to stopping burning fossil fuels, because we will soon need fossil fuels to make food (and other stuff) from. Oh, and also stop burning FOOD. So we should replace fossil fuel power plants with only viable alternative - NUCLEAR. So called renewable power sources like solar are good addition, but doesn't scale to the amount of power and stability we need. -- Hkmaly (talk) 14:12, 15 September 2016 (UTC)

So disappointing to see that Randall Hitler Munroe subscribes to the obviously false "global warming" religion. He should know better. 172.68.55.83 00:11, 16 September 2016 (UTC)

Troll troll trolly trolly troll troll troll 162.158.214.217 03:07, 16 September 2016 (UTC)
https://www.explainxkcd.com/wiki/index.php/261:_Regarding_Mussolini 141.101.98.126 (talk) (please sign your comments with ~~~~)

I understand the concept behind this comic, but why doesn't the graph include atmospheric CO2, sulfur aerosols, and solar 10.7cm radio flux for comparison? Also, for the person who suggested we look at previous interglacial periods, I may be wrong, but I believe a lot of that data comes from ice cores, that would make it hard to look at time periods before the present ice sheets existed. IIRC, there were periods not too long ago (geologically speaking) where Antarctica was covered in lakes, tundra, and sparse forests instead of ice sheets.172.68.65.127 05:08, 16 September 2016 (UTC)

The jump of 0.5 degrees from 2000 to 2016 has been shown to be false. It exists because "scientists" went back and changed (or "seasonally adjusted") their data to fit their preconceived conclusions. Just look at Al Gore's 'Inconvenient [Non]Truth', pretty much every doomsday scenario has not occurred. I expect better of XKCD.173.245.48.77 20:58, 15 September 2016 (UTC)

It would be very nice if they wouldn't spread climate change misinformation. 22,000 year Time line [20,000 BC to 2000 AD] versus 2.5 to 3 billion years of Evolution on a 4 Billion year old Planet

22,000 / 2,500,000,000 = 0.0000088 Using 0.00088 % of Evolutionary History do decide what the weather is supposed to look like. Now an atmospheric history lesson - Cambrian Oxygen 12.5% - Carbon Dioxide 0.45% - Average Temp. 21 °C - sea level 30 - 90 meters - Ordovician Oxygen 13.5% - Carbon Dioxide 0.42% - Average Temp. 16 °C - sea level 180 - 220 - 140 meters - Silurian Oxygen 14% - Carbon Dioxide 0.45% - Average Temp. 17 °C - sea level 180 meters - Devonian Oxygen 15% - Carbon Dioxide 0.22% - Average Temp. 20 °C - sea level 189 - 120 meters - Carboniferous Oxygen 32.5% - Carbon Dioxide 0.08% - Average Temp. 14 °C - sea level 120 - 0 - 80 meters - Permian Oxygen 23% - Carbon Dioxide 0.09% - Average Temp. 16 °C - sea level 60 - 0 - -20 meters - Triassic Oxygen 16% - Carbon Dioxide 0.1750% - Average Temp. 17 °C - sea level 0 meters - Jurassic Oxygen 26% - Carbon Dioxide 0.1950% - Average Temp. 16.5 °C - Cretaceous Oxygen 30% - Carbon Dioxide 0.17% - Average Temp. 18 °C - Paleogene Oxygen 26% - Carbon Dioxide 0.05% - Average Temp. 18 °C - Neogene Oxygen 21.5% - Carbon Dioxide 0.028% - Average Temp. 14 °C - Current Oxygen 20.9% - Carbon Dioxide 0.039% - Average Temp. 15 °C

As you can see an atmosphere when healthy should have Oxygen 25 - 32% Carbon dioxide 0.1 - 0.15% Average Temperature 14 - 18 °C Sea level 60 - 180 meters and there should be no polar ice caps

our sea level is at extinction levels our carbon dioxide is almost too low for plants to survive and our oxygen level is almost suffocatingly low

Less Carbon Dioxide means less Plants Less plants means less Oxygen Less Oxygen means less Life108.162.246.112 07:24, 17 September 2016 (UTC)

I think the point of comics is that while there were changes in temperature before, they were never this rapid. Although I wouldn't be sure about THAT either ... granted, the previous rapid changes were accompanied with mass extinction ... -- Hkmaly (talk) 15:16, 17 September 2016 (UTC)
Yeah, the long sample intervals and best fit curves from pre-industrial temperature estimates tend to smooth out any rapid changes that may have occurred over the time period (Think of an ECG/EKG that took a single instantaneuos microvolt sample once every 15 minutes of your life from birth to death, the resulting deflection graph would not look like anything like a normal heart rhythm, but it could be interpreted as the average electrical activity of your heart over the course of a lifetime). It's true that the rapid climate shifts we are able see in geological records usually coincide with things like supervolcano eruptions and asteroid impacts. But those shifts are usually to the negative end from the nuclear winter effect. Idea for reversing global warming without affecting CO2 emissions, just send a couple of hypervelocity rods or a gravity-tractored asteroid into a dormant supervolcano caldera every few years and... instant winter. 173.245.51.75 02:38, 18 September 2016 (UTC)

Very interesting and important work.

Actually.... Solomon and Jesus are not historical figures. Outside the Old and the New Testament, there is no archaeological or other evidence for their existence. I suppose, Jesus has played a significant role in history. So, you may be justified to add an entry saying something like "Date that religious traditions hold as the date of birth of Jesus."

Then, if you mention, say, Shakespeare, then you should also mention the estimated composition of the Bible, an event with more important historical influences.

Roman empire was continued for more than thousand years (Eastern Roman Empire, today reffered as Byzantium).

Current scholarly wisdom is that the Homeric epics, (the Iliad and the Odussey) were composed at the second half of the 8th century, perhaps around 720 BCE. Konstantas (talk) 05:14, 19 September 2016 (UTC)

Except that no historical evidence has ever contradicted the Bible, and many archaeological discoveries were predicted by it.
According to proper scientific analysis, it is the most accurate historical document(s) in existence. 172.70.51.173 02:19, 11 August 2021 (UTC) Darryl

I wonder if it is getting to be a good time to make a followup, showing the further warming over the last several years and the rightward movement of the 'if we...' paths. 21-Feb-2020

Actual best-case scenario

The actual best-case scenario is far better than Randall's depiction; please see. However, the URLs below in that linked Imgur gallery's first caption were rendered unclickable, probably for spam protection measures, so I reproduce them here:

Actual "best-case scenario assuming immediate massive action to limit emissions"
From https://www.theguardian.com/environment/2013/apr/17/why-cant-we-give-up-fossil-fuels
What will it take to get to this scenario? https://www.solveforx.com/explorations/foghorn/ with http://freenights.txu.com/ and http://co2-chemistry.eu/ for ocean carbonate-sourced plastic composite structural lumber allowing reforestation.

JSalsman (talk) 15:02, 22 September 2016 (UTC)

First, the Guardian is a newspaper, not a science journal. Second, that article is from 2013, before the latest upsurge. Third, even ignoring those things, the article doesn't say what you claim it does. The single most optimistic sentence I see is "If we are lucky, the impact of burning all that oil, coal and gas could turn out to be at the less severe end of the plausible spectrum." The rest of the article is quite pessimistic, such as "it is overwhelmingly likely that we would shoot well past 2C and towards 3C or even 4C of warming."
Please post exact quotes where your links talk about a better scenario. Please do not post URLs and expect us to figure out what you mean. You are making the claim, the burden of proof is on you. - Frankie (talk) 17:13, 5 October 2016 (UTC)
How do you expect me to quote from the graphs? I can't upload images, maybe I need more edits. Please ask any questions you like. JSalsman (talk) 06:14, 1 November 2016 (UTC)
please explain how the Guardian graph you posted on imgur has to do with better scenarios. The title: "Cuts required for 50% chance of not exceeding 2°C". The footer: "CO2 emissions since 1850 (red); exponential growth (blue); cuts to hit climate target (dashed)." It says that in order to possibly reach the "optimistic" +2° scenario (Randall's 2nd line, not the 1st one), we would need to cut anthropogenic CO2 to about 1/10th our current level, which is ridiculously unlikely to happen. The other graphs you posted are just hypothetical extrapolations about energy production that, even if they're trustworthy (which I doubt) don't reference any climate scenarios at all, much less ones better than the timeline. Until you can post a cogent explanation, I will assume you are trolling and undo your edits. - Frankie (talk) 17:19, 2 November 2016 (UTC)
If you extrapolate [1] to 2023-4, renewables dominate, right? Wind has been in competitive equilibrium with coal since 1995, and solar hit grid parity early this year and is expected to continue falling in price about as fast at least until 2035. Is there any reason to believe fossil fuels won't be abandoned by 2030? JSalsman (talk) 02:01, 3 November 2016 (UTC)
Exactly zero words in your explanation discuss how the linked graphs show the existence of a better scenario than the ones listed in the timeline. Your very first graph, from the Guardian, explicitly says 50% chance of not exceeding 2°C, which is Randall's middle scenario. That means it supports exactly what Randall is saying. It says absolutely nothing about a scenario better than the "best case" timeline. - Frankie (talk) 21:06, 3 November 2016 (UTC)
Do you understand the words that I am saying? The words that I have been saying from the start of this conversation? I don't f***ing care about pie in the sky energy projects. Even if your energy claims are correct, they don't say a single d**n thing about beating the +1.2°C curve.. - Frankie (talk) 21:13, 3 November 2016 (UTC)
I apologize. I confused the +1° mark with +2°. The labels are so far above at the top. You are correct. I will forgo uploading the graphs as we are now in agreement. JSalsman (talk) 22:23, 3 November 2016 (UTC)

Joanne Nova

- Frankie (talk) 23:41, 8 October 2016 (UTC)

Interesting Ways to Look at it.

Hey, I had a great time scrolling down and watching the earth heat up :).108.162.245.115 19:47, 17 October 2016 (UTC)

ICYMI, Cato provides an IPCC MAGICC climate model simulator for anyone to examine. FWIW, I side with Bjorn Lomborg, who famously champions a middle way in climate science for the sake of downtrodden peoples around the world. Should we reconsider this explanation in this light? Run, you clever boy (talk)

Fact checking the chart on Stack Exchange

I posted a question on Earth Sciences Stack Exchange about how the Younger Dryas fits into this comic: http://earthscience.stackexchange.com/q/9103/6973

There was also an existing question about the chart's general accuracy: http://earthscience.stackexchange.com/q/8746/6973

--Aaron Rotenberg (talk) 02:53, 14 November 2016 (UTC)

Translation of the Morse code message

The translation of the explanation in "Telegraph", written in Morse code, is: "Now, the mother of Samuel Morse always sent the lad out on a horse." Agusbou2015 (talk) 15:56, 28 May 2017 (UTC)

"Sad comics"

...So after the election of a climate change denier later in the year of this comic's release, several sad comics have been posted. Some of the reason could be that Randall no longer believes that even his worst fears (as expressed by the current path at the bottom) will hold up, when USA gets a president, who will on purpose act in a way that scientist claims will make the temperature rise even more. See more here.

I've mentioned this on the talk page for 2137: Text Entry, but I'll reiterate it here: this observation is not factual, not relevant to the explanation, and does not belong in the description of this comic. If you read it in context, you will see that it is also a non-sequitur, clumsily inserted after one or two factual sentences - it does not follow from anything prior in the discussion. It is poorly expressed and the point being made is unclear in any case.

While the user doing this may well have honest intentions, they are simply defacing articles with their own anti-Trump projections and spamming a link to their own, misleadingly-titled page (Sad comics) which has no clear meaning or explanatory value. Hawthorn (talk) 16:38, 26 April 2019 (UTC)

I have removed the offending paragraph. Hawthorn (talk) 21:20, 26 May 2019 (UTC)