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Old 05-24-2018, 02:49 PM   #1801
Undertoad
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It has to the "best" if it's the "only"

xkcd relies heavily on one particular study of temps (Marcott et al, 2013).

Marcott was the first attempt to reconstruct the temps of the last 11000 years. I think it's still the only one. Science depends on replication of findings, and one single study is not science yet. It's scientific, but it is not "the science".

The study has been criticized. There are plenty of climate scientists who believe the earth has been warmer than it is today. Particularly during the Late Glacial Interstitial, in which Europe and N. America unquestionably saw a period of a lot of warming. That period is not noticed on the xkcd graph, presumably because smoothing? Whatevs, it's one single study and so it gets a big "mmmmmmaybe".
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Old 05-24-2018, 03:16 PM   #1802
Happy Monkey
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Quote:
Originally Posted by Undertoad View Post
Particularly during the Late Glacial Interstitial, in which Europe and N. America unquestionably saw a period of a lot of warming. That period is not noticed on the xkcd graph, presumably because smoothing? Whatevs, it's one single study and so it gets a big "mmmmmmaybe".
Quote:
Originally Posted by wiki
Late Glacial (13,000–10,000 years ago).
That period is indeed noticed on the xkcd chart. There's a noticeable hump. At 13000BC warming accelerates noticeably, then levels and falls back a bit by 10500BC, whereupon it resumes warming.

Relevant events on the graph:
- Glacial dams burst in Washington State
- Ice sheets withdraw from Chicago
- Floods of meltwater in the Atlantic cool Northern Hemisphere (Younger Dryas, as mentioned in the wiki page you provided)




ETA: Apologies; missed mention of Late Glacial Interstadial c.14,670 to c.12,890 in the wiki page. There is no hump there. I find it difficult to parse whathe wiki is trying to say about it, though - it says it is "the first pronounced warming since the end of the LGM", but the "LGM" ends at 13000BC. The previous uptick in temperature in xkcd before 13000 is a bit before 15000.
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Old 05-24-2018, 04:02 PM   #1803
Undertoad
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Interstadial, interstitial, these are hard words

I found an alternate to Marcott, a suggested timeline based on a number of different sources, so Marcott is no longer the only one. Some of this is based largely off an older study so take it with the appropriate grains.

https://andymaypetrophysicist.com/cl...t-18000-years/

The point is, all these proxies are not great measurements and so we are left with huge uncertainty. The uncertainty/error bars are left off the cartoon version... and also, left off every media report about this, ever.
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Old 05-24-2018, 04:12 PM   #1804
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Didn't mean to highlight your typo; that bolding was from the cut&paste.
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Old 05-24-2018, 09:48 PM   #1805
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Both of these studies can be nit-picked ad infinitum but they agree that there have been humongous changes on earth with a temperature swing of less than 15, maybe 20 degrees.
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