At WUWT, we’ve gotten several tips about the XKCD cartoon that makes yet another “hockey stick” out of climate over recorded history. Nylo comments on WUWT Tips and Notes:
Marcott 2013 is still alive! Last to resurrect it is XKCD
Note the references vertically written on the right:
You can view it here: http://xkcd.com/1732/
Two things that make Josh’s take on it better (besides his superior artistic skills):
- The sources used are not just pro climate change like XKCD did
- It is factually correct, rather than illustrating a preferred narrative.
Here is is: prepare to scroll. Some people with lame un-updated operating systems, low RAM, and/or outdated browsers may not be able to see the entire thing.
The reference to Marcott http://climateaudit.org/?s=marcott
Top tip: Visit CartoonsbyJosh and give him a donation.
UPDATE: Chart corrected as per comments – the earlier version was posted before I had a chance to update. Any other comments and corrections are very welcome!
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
1) Y-D drop larger than XK shows, and faster as well
2) Holocene Optimum ~6,000-3,000 bce was 2-4C warmer than present
3) Ceaser fround grapes growing on the England, Scotland boarder. That’s 400 miles farther north than they can be grown today. Temperature must have been warmer than indicated.
4) People in London, England had Ice Fairs on the Thames in winder as river froze over most winters during depth of LIA. Not happening now, so LIA colder than indicated!
5) Stalagmites and stalagtites analysis from caves in Asutralia and China show LIA was world wide event and not just in Northern Hemisphere or Europe.
SInce present temperatures are still below Holocene Optimum 8,000 years ago, forecasts for pending disaster are highly overblown! But you must have a pending tragedy to con people out of money so worthless research can be funded!
But both scrolls were very well done, far beyond my artistic talents!
Perhaps I’m misinterpreting, but I had always liked the xkcd climate change cartoon. It sure made it look to me like past ice ages were a bad thing and a warming world was where you wanted to be.
Like others, I greatly enjoyed Josh’s cartoon. And since you invited comments and corrections, here are a few to consider (with outright apologies for the rather lengthy post required for the relevant data):
1. Ice Ages (per accepted scientific climatology terminology; note use of caps) last tens of millions to hundreds of millions of years, but within an Ice Age there are multiple shorter-term periods of warmer temperatures when glaciers retreat (called interglacials or interglacial cycles) and periods of colder temperatures when glaciers advance (called glacials or glacial cycles). The last Ice Age started around 3 million years ago so technically we are most likely still deep in an Ice Age, but within a warming interglacial period that began 12-14 thousand years ago . . . well before human civilization and any human-originated CO2 emissions, as Josh noted.
Thus, I would hope that we can be more careful about using the phrase “ice age” when the more proper terminology would be “glacial period”.
Over the last million years, glacial events have occurred at an average frequency of about once every 100,000 years. The exact end of the last glacial period is somewhat uncertain: it may have occurred about 14,000 years ago when the Earth’s average global temperature warmed relatively quickly by about 30 deg-F to nearly the average temperature we have today, or it might have occurred at about 12,000 years ago at the end of the Younger Dryas cold period. Climate scientists aren’t sure whether the brief (it only lasted about 500 years) warming period 14,000 years ago or the end of the Younger Dryas cold period (it lasted about 2,000 years) is the real end of the last glacial period.
In any event, the last 12,000 years or so (the Holocene period) has been a period of relatively stable global temperatures, again as noted by Josh.
2. The global warming period that followed Younger Dryas is extremely important because we do not know if the same processes that caused it have not reappeared within the last 200 years, and are therefore the predominant cause of Earth’s recent warming trend. This would further support that mankind is not the primary or even a secondary cause of Earth’s recent warming, often attributed to mankind-related CO2 release due to the burning of fossil fuels.
More specifically:
a) The warming period following Younger Dryas and leading into the Holocene had an average warming rate (about 1 deg-C every 100 years) that is similar to, but higher than, what Earth has experienced over the last 100 years. During this ~2,500 year period of warming, averaged annual temperatures on the Greenland ice sheet hit a maximum warming rate of around 8 °C over 40 years, and the total temperature rise was about 20°C.
b) The warming period following Younger Dryas had an associated large increase in atmospheric CO2 content (from about 190 ppm to 260 ppm, a 37% increase), and this obviously happened without any mankind-related burning of fossil fuels and associated mankind-related release of CO2 into the atmosphere.
c) The transition from the cold minimum of the Younger Dryas period to the start of the rapid warming recovery happened extremely rapidly, on the order of 200 years or less, which interestingly is close to the same duration that Earth has most recently seen a large increase in global warming (i.e., the last 200 years).
d) The warming period exiting Younger Dryas lasted for about 2,500 years, and if the same natural processes that caused this event—and there is no scientific consensus as to what they are—have again become active within the last 200 years, then mankind can do little to prevent this and thus needs to globally concentrate thought and resources for planning how to adapt to/survive a long (1000 years or more) long-term warming period and not how to fight or reverse an overpowering natural climate event (reference Dansgaard-Oeschger events).
e) If the world’s best climate models cannot even back-predict (“hindcast”) the 2,500 year warming exit from Younger Dryas and the world’s best climate scientists have not even explained (reached a “consensus”) on the causes of this warming, then how do we know that the same processes of this warming aren’t happening right now?
f) It appears that humanity is preparing to spend untold TRILLIONS of dollars fighting man-made global warming (AGW)—largely on the basis of “scientific” climate models that forecast most of global warming is AGW and thus requires immediate drastic actions—despite the facts that the Younger Dryas event and its subsequent warming period show that similar rapid global climate change has occurred without any influence from humans.
“If the world’s best climate models cannot even back-predict (“hindcast”) the 2,500 year warming exit from Younger Dryas”
Nobody has even tried. Running a GCM and a Glaciology model in parallell and at a reasonably high definition (say 100×100 km) over a 2,500 year interval would take years and cost billions even on the fastest supercomputers.
tty, you posted: “Nobody has even tried . . . ”
Hmmm . . . I was totally unaware that GCM and glaciology models (huh?) were the only types of climate models that existed with capability to hindcast.
So much, I guess, for ever building a Earth-centric computer model to see if Dr. Milankovitch’s theories correlate to reality.
/sarc
This is outside my skillset, but would a distributed computing system be feasible for climate research, both hindcast and then forecasts? I’m thinking of a project like the seti-at-home or human genome projects.
Sorry, but an orbital model does not count as a climate model. Orbital mechanics are simple.
tty,
It is true that an orbital model is not a climate model, but in the case of Milankovitch, that’s largely a distinction without a difference. One is hard pressed to assert that Milankovitch’s theory of orbital cycles—and critical parameter variations therein (e.g., Earth’s obliquity, Earth’s orbital eccentricity, equinox precession, etc.)—have not been used as the basis of MODELING how those variations affect solar insolation which in turn is the primary driver of Earth’s climate.
Heck, here’s what NOAA has to say about this: “The Milankovitch or astronomical theory of climate change is an explanation for changes in the seasons which result from changes in the earth’s orbit around the sun. . . . Orbital changes occur over thousands of years, and the climate system may also take thousands of years to respond to orbital forcing. Theory suggests that the primary driver of ice ages is the total summer radiation received in northern latitude zones where major ice sheets have formed in the past, near 65 degrees north. Past ice ages correlate well to 65N summer insolation (Imbrie 1982).” (source: http://www.ncdc.noaa.gov/paleo/milankovitch.html )
I could go on and on, but why bother.
So, if you want to imply, as you did earlier, that only GCM and Glaciology models qualify as the “best climate models”, especially in terms of hindcasting, go ahead and be my guest.
But please consider that there are useful theories and associated models that correlate well paleoclimate data records (e.g., that of Milankovitch), and then there are other models (most notably tens of currently-used GCMs) that don’t even correlate well with each other, let alone having any accuracy in predicting climate ten years into the future . . . as the IPCC and this website have clearly demonstrated.
Categories of climate models currently in use:
0-D EBM
1-D EBM
2-D EMIC
3-D EMIC
GCM
OGCM
AGCM
CGCM
(source: http://www.climate.be/textbook/chapter3_node4.html )
0-D EBMs are simple.
The 8.2 KA cold event was bigger and sharper than in the timeline. And sabretooths stopped roaming North America just before, not just after Younger Dryas. The youngest reliable date is 11,130 BP, but this is in radiocarbon years which are about 10% lower than calendar years in this range.
I think that the thing the xkcd cartoon brought to mind was how it chose a narrow section of time. If you look at a chart by the Smithsonian – one that does not purport to have anything to do with global warming – then you can easily see that over the course of human evolution the temps have been getting cooler but the amplitude of the changes in temperature have become larger: http://humanorigins.si.edu/evidence/human-evolution-timeline-interactive
There are also a couple of nitpicks I can add to the excellent version of the chart that Josh made: I believe that farming started in Europe before the Younger Dryas as well – we had to go back to hunting and herding until the weather improved. (I do not know if the rice cultivation in China was put on Pause for the Younger Dryas.) Also, the development of writing per se might be added (as opposed to alphabetic writing).
Thank you for the corrected chart.
Jan
“I believe that farming started in Europe before the Younger Dryas as well – we had to go back to hunting and herding until the weather improved.”
No, farming didn’t come to Europe until long after Younger Dryas, but it seems to have started in the Near East during Younger Dryas.
Timeline’s final 2,500-year scale is inconsistent with previous 500-year intervals, compressing periods 40% to 300 years. Might also note that the so-called Younger Dryas “cold shock” was verifiably an artifact of episodic cometary/meteorite impacts, wholly unrelated to Earth’s climatic or equinoctial precessional regimes.
Also, a rudimentary geophysical –plate tectonic– plot of “drifting” continental landmasses would be apropos, tying cyclical Pleistocene Ice Ages to North and South American continental dispositions’ interference with global atmospheric/oceanic circulation patterns as well as long-term fluctuations in total solar irradiance (TSI).
Needless to say, willfully deviant Klimat Kooks, the new Lysenkoists/Anabaptists of Munster, will go to any lengths to suppress empirically objective or even rational scientific fact.
LLoyd, please cite a scientifically-credible reference (or two) to support your statement that the Younger Dryas cold period was “verifiably an artifact of episodic cometary/meteorite impacts” . . . emphasis on VERIFIABLY as opposed to hypothetically.
According to Wikipedia (https://en.wikipedia.org/wiki/Younger_Dryas_impact_hypothesis ): “The Younger Dryas impact hypothesis, also known as the Clovis comet hypothesis, is one of the competing scientific explanations for the onset of the Younger Dryas cold period after the last glacial period. The hypothesis, which scientists continue to debate, proposes that the climate of that time was cooled by the impact or air burst of one or more comets.[1][2][3]. ” And further on: “Recently new studies were published in the matter of the YDB impact hypothesis, criticizing the methodology and pointing to inconsistencies regarding the chronological data.[59][60][61] This new research, which analyzed sediments claimed, by the hypothesis proponents, to be deposits resulting from a bolide impact were, in fact, dated from much later or much earlier time periods than the proposed date of the cosmic impact. The researchers examined 29 sites that are commonly referenced to support the impact theory to determine if they can be geologically dated to around 13,000 years ago. Crucially, only three of the sites actually date from that time. According to the researchers, the Younger Dryas impact event evidence “fails the critical chronological test of an isochronous event at the Younger Dryas onset, which, coupled with the many published concerns about the extraterrestrial origin of the purported impact markers, renders the Younger Dryas impact hypothesis unsupported. There is no reason or compelling evidence to accept the claim that a cosmic impact occurred about 12,800 years ago and caused the Younger Dryas.[59]”
Perhaps your definition of “verifiable” is different from mine and that of the scientists who wrote those papers referenced in the Wikipedia article?
Now, you were saying something about “empirically objective or even rational scientific fact” . . .
I was about to share this on social media then noticed the 2000 to 2016 period is indeed completely wrong and reflects the original comic’s erroneous attribution of a steep incline when in fact it was flat.
A pity, fix that and it’s useable, despite some of the astute observations of posters here about missed warmings thousands of years ago.
It would’ve been better if he’d used the same scale with a clear 2000 to 2016 demarcation to demonstrate the difference and lack of warming.
Still, great work!
I posted this chart to Slashdot after someone posted the XKCD one. The post was modded up more than down and ended at 4. A few years ago it would have been at -1. There were lots of encouraging replies showing that people are thinking instead of blindly following. https://slashdot.org/comments.pl?sid=9703345&cid=52966897