Explain xkcd: It's 'cause you're dumb.
Title text: 'You see the same pattern all over. Take Detroit--' 'Hold on. Why do you know all these statistics offhand?' 'Oh, um, no idea. I definitely spend my evenings hanging out with friends, and not curating a REALLY NEAT database of temperature statistics. Because, pshh, who would want to do that, right? Also, snowfall records.'
In this comic, White Knit Cap Guy and Black Knit Cap Guy are walking outside in sub 0 °F (-17.8 °C) White Knit Cap Guy complains about the brutal cold and uses it as evidence that global warming is not real. Black Knit Cap Guy explains that this kind of weather used to happen all the time back before the year 2000.
This is illustrated in panel two by a graph showing the number of days with sub 0 °F as a function of year from 1970 to 2013 in the city of St. Louis, (where we learn that White Knit Cap Guy is from). It shows that these days used to be rather common between 1970 and 1999, only to be completely absent for the next 14 years until and including 2013. A rcc-acis.org/climatecentral source link for this graph is provided (though as of June 2014, the link is dead - see Trivia below).
Black Knit Cap Guy uses this graph to explain that not a single day like this has happened since 2000, until here in 2014 where a polar vortex pushed the temperature down below zero again for two days. This caused many people to react as if it had never been this cold before. He goes on to explain that since this weather is now unusual, we perceive it as being more cold, even though this was a common temperature to reach in past decades. However, White Knit Cap Guy continues to insist that it is too cold, demonstrating he learned nothing from their talk. Subzero Fahrenheit temperatures are very cold to be out in. See for instance the first panel of 526: Converting to Metric.
In the last panel, in a future St. Louis, a Cueball discovers a thin sheet of ice, suggesting the temperature has fallen just below 32 °F (0 °C), the freezing point of water. The suggestion here is that the environment has warmed to such an extent that temperatures below 32 degrees are very unusual, and the future Cueball repeats the same short-term fallacy that such "extreme cold" disproves global warming. Someone off-panel, presumably another Black Knit Cap Guy, sighs as the cycle continues.
The comic reacts to a simplified view of global warming by amateurs, including media, who fail to understand (or choose to ignore) the difference between climate and weather. Short, random weather fluctuations like the polar vortex are taken as examples or counter-examples of climate change and global warming. To understand climate change, one must look at global (not local) and long-term (not short-term) temperature trends.
Debates on the theory of global warming/climate change often center on whether the current warming trend is primarily caused by humans or is a natural change, as has happened in the past. Within the scientific community, there is an overwhelming consensus that the current trend is anthropogenic (i.e. man-made), but many in the general public (including many politicians) are hesitant to accept this. There is clearly no doubt about where Randall stands on this debate, as many of his comics and blog posts continue to plead for humanity to do something about the man-made global warming trend - especially in comic 1379: 4.5 Degrees.
The title text suggests that gathering data about global warming is time-consuming and is the kind of stuff only a real nerd would do. Most people would rather hang out with friends, or at least spend their time with some more fun nerd activity. Randall has been known to use the title text to poke fun at himself over how much time he has spent researching topics and more generally how geeky his interests tend to be. Although the title text tries to deny this geeky behavior, he cannot help himself at the end by mentioning another interesting climate subject: Snowfall records.
More comics referring to global warming:
- [It's cold, two Guys wearing knit caps (one knit cap is white the other black) are walking outside and the White Knit Cap Guy is shivering.]
- White Knit Cap Guy: It's brutal out. So much for global warming, huh?
- Black Knit Cap Guy: *sigh* This used to happen all the time.
- White Knit Cap Guy: What?
- [A bar graph relating the number of days with lows below zero Fahrenheit by year since 1970.]
- Black Knit Cap Guy (off-screen): You're from St. Louis, right?
- Black Knit Cap Guy (off-screen): On average, it used to get below 0 °F there a handful of days per year.
- Black Knit Cap Guy (off-screen): But you haven't had a day like that since the nineties.
- [Above the bar graph to the left is a label in a black frame:]
- Days with lows < 0°F
- [Below the graph are written the years:]
- 1970 1980 1990 2000 2010
- [Below again is written in small letters:]
- Source: rcc-acis.org/climatecentral
- [Black Knit Cap Guy has stopped walking.]
- Black Knit Cap Guy: Then, in 2014, when the first polar vortex hit, it dipped below zero for two days. And everyone freaked out.
- [They continue walking.]
- Black Knit Cap Guy: Because what used to be normal now feels too cold.
- White Knit Cap Guy: It is too cold!
- [Above the last panel is written in a black frame:]
- The Future:
- [Cueball is pointing at a patch of ice.]
- Cueball: Look at this—ice! In St. Louis! So much for global warming.
- Person off-screen: *sigh*
- The link to the source rcc-acis.org/climatecentral is dead. rcc-acis.org/ leads to the home page of ACIS which stands for Applied Climate Information System and this page is still on-line. But it seems like the climatecentral part of the source link, is now relocated to Climate Central's own web page: climatecentral.org/.
- The graph can still be found in Climate Central's assets. The graph is used to illustrate the point in the following article: Extreme Cold is Becoming More Rare were similar graphs are shown or referenced for many other US cities.
- From the graph the following info can be found:
- During the 30 years before 2000 there were 89 days with subzero Fahrenheit temperatures, averaging almost three a year.
- During that period there were only one occurrence where there were two years in a row with no subzero days. This was then followed by a gap of 14 years without.
- The maximum was 13 subzero days in 1984, but no less than three years had more than 10 subzero days.
- As these record years all lay in the 8 year period from 1977 to 1984, no less than 52 of these 89 subzero days occurred in those years.
- Here are the number of days from 1970 to 2000 as read of the graph:
- 1970 - 4; 1971 - 0; 1972 - 4; 1973 - 0; 1974 - 4; 1975 - 0; 1976 - 1; 1977 - 11; 1978 - 5; 1979 - 8; 1980 - 1; 1981 - 3; 1982 - 11; 1983 - 0; 1984 - 13; 1985 - 2; 1986 - 1; 1987 - 0; 1988 - 1; 1989 - 0; 1990 - 5; 1991 - 0; 1992 - 0; 1993 - 1; 1994 - 3; 1995 - 0; 1996 - 3; 1997 - 6; 1998 - 0; 1999 - 2; 2000 - 0;
- Compared with the graph in the link above, there is one mistake in Randall's version, as there were two days not only one day in 1976 according to the on-line graph.
 NOAA data for St. Louis
Note that this is not the same data set as mentioned in xkcd as this is regarding freezing days and not subzero days!
With the full excel dataset of the number of freezing days (i.e. below 32 °F) as obtained from the National Oceanic and Atmospheric Administration's homepage NOAA you get the following plot:
- Blue points: Number of freezing days (<32 °F) for that year
- Red points: Number of freezing days averaged over 10 years (to make trending more readable)
- X-axis is the year (1874..2013)
- Y-axis is the number of days temperature is below 32 °F for St. Louis
From the same dataset excel dataset we can also get the number of sub-zero days i.e. below 0 °F (which are those mentioned in the XKCD strip) - plotting those and you get the following plot:
Note that this IS the same data set as mentioned in XKCD. This is subzero days!
- Blue points: Number of sub-zero days (<0 °F) for that year
- Red points: Number of freezing days averaged over 10 years (to make trending more readable)
- X-axis is the year (1874..2013)
- Y-axis is the number of days temperature is below 0 °F for St. Louis
While there were a number of very cold years with outliers in the nineteenseventies - then the clear overall trend is still that there are fewer days with cold weather over the years.
So while weather is different every year (which is also illustrated by the outliers) the climate is defined by the long term trend - which is the point of this cartoon.
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If you are not familiar with the US language some of the abbreviations used below makes it difficult (although still funny) to read the comments... But here are the explaination of two that are used more than once:
- POV: Point of view
- AGW: Anthropogenic Global Warming
Kynde (talk) 19:35, 29 June 2014 (UTC)
I really hate when articles on science get a POV tag. Science isn't politics (hint: evolution and gravity aren't POV either). Related to the comic, I just had a similar rant on Facebook in the last week or two where I linked to this article when someone said it was too cold for Global Warming. 22.214.171.124 12:24, 24 January 2014 (UTC)
- Actually evolution is a POV. For a start, it absolutely depends on the non-scientific assumption/philosophy/belief that there is nothing other than the material universe. 126.96.36.199 01:59, 29 January 2014 (UTC)
- Why do you think evolution depends on such a thing? In other words, if there were anything other than the material universe, why would that rule out evolution? 188.8.131.52 17:01, 3 February 2014 (UTC)
- Evolution is so ridiculously unlikely that just about any explanation involving a non-material cause is more likely. 184.108.40.206 10:21, 8 July 2014 (UTC)
I really hate it when people think the global warming scam is science, when it really is nothing more than politics masquerading as science. The IPCC has been proven to be a bunch of liars, and really there's nothing left but a bunch of whining left-wing lunatics who are desperately clinging to their hope of continuing to use this lie to raise energy prices/taxes. 220.127.116.11 12:55, 24 January 2014 (UTC)
- Well you're wrong, and apparently delusionally paranoid about what the political left wants, but the bigger question is why is this in a wiki discussion page? 18.104.22.168 13:21, 24 January 2014 (UTC)
- No, you are wrong, and still buying into the AGW myth that has been proven false (IPCC and others were basically caught lying). Why is this in a wiki discussion page? Well, apparently Randall has decided to use his webcomic as a vehicle to promote a left-wing agenda, so discussion of it here is totally legit. 22.214.171.124 14:03, 26 January 2014 (UTC)
- I think the most important words there are "his comic", so it's his call on what he writes. Also, honestly, the idea that climate change is a scam to control energy prices is pretty absurd.Pennpenn (talk) 13:39, 28 January 2014 (UTC)
- Also, I thought it was well-known that Randall was a liberal. He's made it pretty clear in the past which side of the fence he's on politically. But that's beside the point, and I agree with 126.96.36.199: You honestly would have to deliberately choose to ignore the whole of the scientific community to believe that the concept of climate change is some sort of political scam. It really isn't - you can see evidence of it everywhere, if only you were to open your eyes and take a look around you. 188.8.131.52 01:38, 29 January 2014 (UTC)
- Evidence of what? That's what makes insistence so irrational and, when pushing policy, dangerous. With a millionth of geologic time in empirical evidence and tons of extrapolation, you've got daisy-chained assumptions all the way to end-times superstition. It's downright medieval. If the "scientific community" actually speculated that warming might lengthen growing seasons, expand habitability and bring other benefits, the effort might look somewhat objective. But instead, the only understanding of warming is ineluctable catastrophe straight out of a Hollywood screenplay. Seriously, step back and contemplate how insane that is. Every five years someone claims the world has five years left. Actually, I'd say "it was five years ago people claimed hurricane intensity would increase because reasons," but it was nine years ago, and nothing happened. Well, intensity dropped. And yet, ironically, like the characters in this strip, people desperate to believe in a meteorological eschatology will seize at anything -- anything at all -- to threaten and shame others for not accepting that industry means carbon dioxide means temperature change means ??? means doom. 184.108.40.206 23:50, 30 January 2014 (UTC)
- Amongst other falsehoods 220.127.116.11 tells this science denier whopper: "the AGW myth that has been proven false (IPCC and others were basically caught lying)." It is you who is telling lies 18.104.22.168 - wittingly or otherwise. But hey if you disagree then tell us exactly how, in your mind, AGW Theory has been "proven false". 22.214.171.124 (talk) (please sign your comments with ~~~~)
Although it doesn't directly mention it, this is partly related to people's confusion over the difference between 'weather' and 'climate' - the former being what the conditions are at a given moment in time, and the latter referring to long-term trends.126.96.36.199 14:52, 24 January 2014 (UTC)
I think the one with whit wolly hat is whitehat Halfhat (talk) 16:10, 24 January 2014 (UTC)
Can anyone provide an exact URL for (or procedure for finding) the data shown in the upper-right panel? --188.8.131.52 18:00, 26 January 2014 (UTC)
Randall has cherry picked data for his conclusion and the graph in the comic. The full history is available from the NWS. The one for my home town can be found here http://www.erh.noaa.gov/iln/climo/below0.php The 1970's were unusually cold, which makes the present seem warmer by comparison. --184.108.40.206 16:33, 24 January 2014 (UTC)
- All of those show a dropoff in frequency of below-zero temps since the 90s. 220.127.116.11 17:08, 3 February 2014 (UTC)
Apparently Randall hasn’t seen this:
- No, that's not at all apparent. Perhaps he has. But the character in the white hat doesn't have a memory going back that far, so it isn't relevant. 18.104.22.168 17:08, 3 February 2014 (UTC)
To quote Michael Z. Williamson:
29 years in the last century is not an "average" of the last 300 million years.
Any finding based on that "average" is complete bullshit. You may as well use 1300-1305 hours on Apr 23 as your "average." You'll be about as accurate, and save time over actual data collection. 22.214.171.124 (talk) (please sign your comments with ~~~~)
The claim that 0 Fahrenheit / -17 Celsius is really fucking cold is supported by 526: Converting to Metric. Fryhole (talk) 00:41, 25 January 2014 (UTC)
- We've been getting some ball-chilling winter with the cold fronts suddenly appearing in Florida, which is a drastic change from the sweaty weather just last week. I've added "fuckfuckfuckcold" to my personal lexicon. 126.96.36.199 04:16, 25 January 2014 (UTC)
Is that possibly WHITE HAT not CUEBALL (except for the last panel)? 188.8.131.52 (talk) (please sign your comments with ~~~~)
The one in black is not black hat.
He sits around memorising weather data, and lack malice. Halfhat (talk) 18:29, 25 January 2014 (UTC)
Can anyone provide an exact URL for (or procedure for finding) the data shown in the upper-right panel? 184.108.40.206 18:00, 26 January 2014 (UTC)
The source rcc-acis.org/climatecentral provided by Randall doesn't work. What's wrong? --Dgbrt (talk) 21:30, 26 January 2014 (UTC)
- The source quoted on xkcd is no long a URL, but simply "'rcc-acis/climatecentral'" Boxy (talk) 03:07, 27 January 2014 (UTC)
- ClimateCentral made some graphs based on rcc-acis data for a few dozen cities. Here is the link In Much of U.S., Extreme Cold is Becoming More RareJamesprescott (talk) 19:16, 28 January 2014 (UTC)
Oh Dear. I can't believe what I'm reading. Either you guys are being ironic or Randall needs to expand his comic to encompass some of you.220.127.116.11 09:00, 28 January 2014 (UTC)
I'm really surprised that so many people could love xkcd (apparently) but also hate science. 18.104.22.168 (talk) (please sign your comments with ~~~~)
- Despite missing links in evolution tree and missing Quantum gravity theory, we know much more about both that about the climate. Climate politics isn't actually based on science, as scientists failed to produce results fast enough. I would really like to see science result on global warming, but with the amount of money at stake, I don't believe I can. Maybe later. Also, it's a pity that the global warming discussion shadowed REAL ecologic problems. I don't need global warming to see that burning fosil fuels is bad idea. -- Hkmaly (talk) 01:25, 29 January 2014 (UTC)
- Not quite so fast, there. 'Can you tell me anything you know about evolution, any one thing that is true? I tried that question on the geology staff at the Field Museum of Natural History and the only answer I got was silence. I tried it on the members of the Evolutionary Morphology Seminar in the University of Chicago, a very prestigious body of evolutionists, and all I got there was silence for a long time and eventually one person said, "I do know one thing -- it ought not to be taught in high school".' Dr. Colin Patterson (Senior Paleontologist, British Museum of Natural History, London). Keynote address at the American Museum of Natural History, New York City, November 5, 1981. 22.214.171.124 01:59, 29 January 2014 (UTC)
- To those of you who claim climate change is a scam: Have you ever actually looked at any one of the hundreds, perhaps thousands, of science papers, studies, documentaries and photo comparisons done on the polar ice caps and mountain glaciers around the world? Have you ever looked at the Great Barrier Reef off the east coast of Australia? Are you even aware that drastic and very sudden changes have happened to these things in just the last 20 years? (And in the case of the Reef, the two major bleaching events in 1998 and 2002 occurred over just a few DAYS each.) These are things that existed, mostly unchanged, for thousands of years and are suddenly disappearing or being damaged beyond repair. The evidence is overwhelming. I have a really hard time believing that anyone can be faced with such extreme evidence and choose to just plug their ears and go "LA LA LA, LIBERAL LIES" like you morons are doing. 126.96.36.199 01:47, 29 January 2014 (UTC)
- (To be frank, the people I'm referring to here sound like they came from this comic: http://www.explainxkcd.com/wiki/index.php/258:_Conspiracy_Theories ). 188.8.131.52 01:56, 29 January 2014 (UTC)
- You said it yourself. "Climate change". I agree that anyone denying the climate is changing is ... how did you said it ... moron. What I'm challenging is the belief that if we tax production of carbon dioxide (or implement some other of plans "against global warming"), the climate will change back. There's nothing scientific on that. Especially considering how low is chance that any taxing would actually lower amount of carbon dioxide produced globally ... usually, it only causes businesses to relocate. Another thing I'm challenging is the "unprecedented" bit often used by global warming proponents. Geologically speaking, climate changes happens often ... and scientists have very little or no data on previous changes. What is few thousands of years in history of Earth? (And in fact, we don't even have data for those thousands of years. We have data for few last hundreds top.) -- Hkmaly (talk) 10:37, 29 January 2014 (UTC)
- Okay, it wasn't clear earlier that your point was about USING climate-change as a means to scare people into paying taxes, etc. I saw often-repeated arguments that climate-change ITSELF is a myth and a political football - that there's no proof it's happening. I can understand questioning political actions taken as a result of the science, but the fact that the climate is changing is undisputable.
- As for whether this form of climate change is unusual in the grand scale of time, you're right that we don't have detailed records going back more than a few hundred years, and ecologically speaking, that's not a long time. But we DO have direct evidence that humans are responsible for a significant portion of the current change, including the incredibly sharp increase in global human population in just the last 100-150 years. And my point is that there really are people out there who firmly believe the scientific community is smoking crack and promoting some dastardly political agenda, and all the photos and documentation of mass coral bleaching events, glacier and ice-cap melt, species extinctions, etc., are all elaborate hoaxes. (Just like us landing on the moon, right?) 184.108.40.206 23:59, 29 January 2014 (UTC)
- Amongst other climate science denier talking points Hkmaly sets up this straw man: "What I'm challenging is the belief that if we tax production of carbon dioxide... the climate will change back." The notion that if we reduced greenhouse gas emissions then the "climate would change back" is nothing but a climate science denier straw man. AGW Theory does not say that - it instead says that due to man-made greenhouse gases already in the atmosphere the globe will continue to warm the Earth no matter what we do, and also that if we reduced greenhouse gas emissions then future global warming will be mitigated.
- Hkmaly also repeats this science denier falsehood: "And in fact, we don't even have data for those thousands of years." And if fact, you are wrong: we have temperature proxy data going back for not only thousands of years but for far longer than that too. 220.127.116.11 (talk) (please sign your comments with ~~~~)
- I don't care what AGW Theory says. I care about what politicians says, because THAT will influence the world. And politicians says we need to reduce carbon dioxide production and everything will be ok. It won't. We should start adapting. (Although stoping burning fossil fuels is also good idea, as I already said.) Also, we don't have direct measurements of those thousands of years. Proxy data are not as reliable as direct measurements AND are less reliable the further in past we get (because only the less reliable methods works for long periods). Now, about other points: the rise of human (and wheat) population may be MORE dangerous than the rise of industrial carbon dioxide, but it's not mentioned as often, because most politicians are not ready do DO something with rising human population (and the ones who DO - like Bashar al-Assad - are not doing it because of global warming). Also, the species extinction is certainly bad thing, but most species go extinct because of things totally unrelated to global warming - things more obviously caused by humans, BTW. Things which don't get as much coverage and support as global warming. Probably because there is not enough money there. -- Hkmaly (talk) 10:31, 25 June 2014 (UTC)
- The reason that AGW gets more attention than overpopulation or habitat destruction is that (1) it's easier to quantify, (2) our current actions matter more, and (3) we have solutions that don't involve killing or starving people. If you're worried about water shortages due to overpopulation, those 3 reasons will stop you. (1) How much time and money do we have to actually invest, and how many people will it help; (2) why don't we just make that technology later when it becomes a problem; and (3) no one wants to touch the issue of restricting population growth to reduce land/water consumption. On the other hand, with AGW, it's easier. (1) We know the relative costs of fossil fuels and renewable energy, and we have tentative estimates of the damage climate change can cause. Also, the cost of a carbon tax and its effect on the economy aren't too hard to figure out; (2) we can't just push it under the rug like other issues. If we ignore it completely right now, we'll be stuck with a 5-10 degree F increase by 2100; and (3) It involves no killing or restricting basic rights - you can mitigate climate change just by setting taxes or trade quotas. Sure, those aren't particularly popular, but it's easier on the conscience than killing people off. Also, although the effects of climate change are sometimes exaggerated, they are still on the same level as the other ecological problems. Sure, our current 1.5 degrees of warming hasn't done much damage, but that's because it's within the earth's natural variation. Add on another 5+ degrees and it'll get tough for quite a few biomes. When a heat wave hits on top of that, you're just begging for extinctions, or at least a large drop in genetic diversity. I agree that other ecological issues are overshadowed by AGW in the media, but that doesn't discredit the importance of dealing with AGW.18.104.22.168 04:50, 28 June 2014 (UTC)
Isn't the point of this one the fact that the cold days standing out being part of the point. People use rare cold snaps to question global warming, but they're ignoring the fact that the cold snap wouldn't be that out of the ordinary years ago. 22.214.171.124 (talk) (please sign your comments with ~~~~)
It's not GulfStream that matters, it's the proximity to the ocean that keeps the temperatures moderate. Seattle is located much farther North than St. Louis AND next to an arctic cold ocean stream, yet it's much warmer in the winter (and colder in the summer). The dry continental air has much higher temperature differences between the summer and winter. The pattern of the mountain chains in the North America tends to bring the cold arctic air from the North to the middle of the continent. Also, 0F/-18C is not brutally cold, it's moderately cold. -40 (either C or F) is brutally cold.
126.96.36.199 05:11, 2 February 2014 (UTC)
An article about Gulfstream: http://www.scientificamerican.com/article/new-simulations-question-gulf-stream-role-tempering-europes-winters/ 188.8.131.52 05:24, 2 February 2014 (UTC)
- I wrote that 0F/-18C is fucking cold, just to emphasize human feelings about that temperature. Someone changed this to brutall. And the Gulf Stream is just one example to show Europeans how different the climate can behave. And of course the northern American climate is not covered by this.--Dgbrt (talk) 21:23, 2 February 2014 (UTC)
- To those of us who constantly live with much lower temperatures, that's not that cold at all. In fact, -18*C in the middle of winter would be a warm day. It'd be better to validate your statements with locational data supporting it, such as, "Floridians would go mad if it snowed" or "If all the snow melted on time, Canadians would go crazy". 184.108.40.206 14:22, 9 February 2014 (UTC)