Interesting graph of Greenland Temperatures

[Nederland]

It puts current conditions in a historical context:




Data taken from NOAA ice core records: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2_temp_accum_alley2000.txt

[Statistical]

1. Has it ever been explained what caused the 3 previous warmings or the abrupt change?

Thanks for the chart I knew about the Medieval warming period but had no idea about the 2 prior ones.

[joshcryer]

10. It was a localized event over Greenland, it wasn't a global event.

There's still debate about the cause.

[Nederland]

16. Actually

There is still considerable debate over whether or not it was a local or global event. The Wikipedia article on the subject notes the following:

An ice core from the eastern Bransfield Basin, Antarctic Peninsula, identifies events of the Little Ice Age and Medieval Warm Period.<26> The core shows a distinctly cold period about AD 1000–1100, illustrating that "MWP" is a moveable term, and that during the "warm" period there were, regionally, periods of both warmth and cold.

Corals in the tropical Pacific Ocean suggest that relatively cool, dry conditions may have persisted early in the millennium, consistent with a La Niña-like configuration of the El Niño-Southern Oscillation patterns.<27> Although there is an extreme scarcity of data from Australia (for both the Medieval Warm Period and Little Ice Age) evidence from wave-built shingle terraces for a permanently full Lake Eyre<28> during the ninth and tenth centuries is consistent with this La Niña-like configuration, though of itself inadequate to show how lake levels varied from year to year or what climatic conditions elsewhere in Australia were like.

Adhikari and Kumon (2001), whilst investigating sediments in Lake Nakatsuna in central Japan, verified the existence there of both the Medieval Warm Period and the Little Ice Age.<29>

"Temperatures derived from an 18O/16O profile through a stalagmite found in a New Zealand cave (40.67°S, 172.43°E) suggested the Medieval Warm Period to have occurred between AD 1050 and 1400 and to have been 0.75°C warmer than the Current Warm Period."<30> The MWP has also been evidenced in New Zealand by an 1100-year tree-ring record.<31>

26. ^ Khim, B-K; Yoon H.; Kang C.Y.; Bahk J.J. (November 2002). "Unstable Climate Oscillations during the Late Holocene in the Eastern Bransfield Basin, Antarctic Peninsula". Quaternary Research 58 (3): 234–245(12). doi:10.1006/qres.2002.2371. http://www.ingentaconnect.com/content/ap/qr/2002/00000058/00000003/art02371. Retrieved 2006-05-04.
27. ^ Cobb, Kim M.; Chris Charles, Hai Cheng, R. Lawrence Edwards (July 8, 2003). "The Medieval Cool Period And The Little Warm Age In The Central Tropical Pacific? Fossil Coral Climate Records Of The Last Millennium". The Climate of the Holocene (ICCI) 2003. http://www.pac.ne.jp/IUGG2003/EN/program.asp?session_id=MC12&program_id=022025-1. Retrieved 2006-05-04.
28. ^ Allen, Robert J.; The Australasian Summer Monsoon, Teleconnections, and Flooding in the Lake Eyre Basin; published 1985 by Royal Geographical Society of Australasia, S.A. Branch; ISBN 0909112096
29. ^ Adhikari DP, Kumon, F. (2001). "Climatic changes during the past 1300 years as deduced from the sediments of Lake Nakatsuna, central Japan.". Limnology 2 (3): 157–168. doi:10.1007/s10201-001-8031-7.
30. ^ Wilson, A.T., Hendy, C.H. and Reynolds, C.P. 1979. Short-term climate change and New Zealand temperatures during the last millennium. Nature 279: 315–317.
31. ^ Cook E.R., Palmer J.G., D’Arrigo R.D. (2002), "Evidence for a ‘Medieval Warm Period’ in a 1,100 year tree-ring reconstruction of past austral summer temperatures in New Zealand", Geophysical Research Letters, 29, doi:10.1029/2001GL014580.

[joshcryer]

25. Fair enough, but our reconsturctions show that we are globally, higher than MWP.

[Viking12]

2. Umm no, it doesn't put current conditions in historical context.

a) We're not witnessing Dansgaard-Oeschger event like the Younger Dryas and b) central Greenland is not a representation of global conditions.

Joanne Nova? Really that's your source for this graph? Why do you try to hide it?

[Nederland]

8. Interesting Observation

I find it interesting that you think it is significant who created the graph. Given that the data comes from NOAA, why does it matter who created the graph? I was under the impression that one of the central premises of scientific method is that authority is irrelevant, only empirical data matters. In other words, it doesn't matter if the ideas or conclusions are coming from a Nobel prize winning scientist, a first year grad student, or a 12 year old kid. If the data is correct, the presenter is irrelevant.

Odd that you think otherwise.

[joshcryer]

11. The graph isn't capable of filling the picture for the past 100 years or so.

We know, though, that we could not drill a GISP3 in the same relative location of GISP2 and get accurate results.

'cause the darn ice has melted there.

[Nederland]

15. True

However, I don't understand your point. The fact that the last 100 years are different is clearly indicated by the color of the line changing from blue to red. There is no attempt at deception in the graph.

[Viking12]

17. ...and what's the source of the data for the last 100 years?

Unless otherwise identified, I'm assuming some denier drew it in with crayon.

[Nederland]

18. Are you blind?

The source of the data is clearly labeled on the graph and specifies the author, article title, and journal from which the data came from.

[Viking12]

19. Are you mathematically illiterate?

What is 0.0951409(1000)? Where's the source for the data of the last 105 years? If you can't identify a source for the last 100 years supposedly represented on the graph, how can you suggest this "puts the current condition in historical context"?

[joshcryer]

23. Because the core was made in 1993 it's actually missing the last 122 years.

[Nederland]

26. Thank you

In other words, all the data comes from the source specified on the graph. But is it the last 122 years, or the last 95?

[Viking12]

27. So you admit that the data provided say nothing about the last ~100 years.

Thus, the graph does nothing to put "current conditions in historical context" and your OP was idiotic and you owe everyone here an apology.

[Viking12]

28. I used the publication date, 2000 as the benchmark.

.095(1000)+10=105 years. 1993 might be the better starting point but the literature doesn't make that clear. It doesn't become any more clear after reading Alley et. al. (2000) (which BTW does not mention the 20th century, desptie what certain trolls may think)

[joshcryer]

21. Actually, the source provided ends 100 years ago.

[Viking12]

12. It does matter when the source has a well-documented history of distortion

I don't have time to run the numbers myself, but from examining Alley's original article it is pretty clear the graph is a misrepresentation of the data.

Funny how you ignore completely the substantive problems with your post. Typical denier tactics.

[Nederland]

14. Are you claiming distortion?

Has the NOAA data been improperly displayed on the graph?

[joshcryer]

22. It's more that you are reading it incorrectly due to how the graph is presented.

The red line is not representative of the last 100 years, though it's clear you believe it is. :(

Easy to fall for though.

[joshcryer]

24. It would be nice for a source, so that those presenting it can be better informed.

[kristopher]

32. Horsecrap

Data is coupled with reasoning, and when a person is clearly associated with deliberate distortions of the data through false reasoning, the knowledge of that persons past efforts is fundamental to what is presented in public discussion.

That is one of the problems the process of peer review is designed to guard against.

Of course you know all of that, which is why you hide the authorship and attempt to downplay the sins of the author.

[Birthmark]

3. It puts current conditions in a historical context...

...in Greenland...assuming it's accurate and representative.

HINT, for those of you playing at home: Greenland is not the entire Earth. It DOES, however, have local weather. ;)

[guardian]

4. Your big mistake

is that the time scale is too long. You only want to show the last 150 years. That way the temperature increase looks dramatic and you can needlessly scare the bejesus out of people with predictions of DOOM!

Can you imagine the chaos it would cause if all the doomer scientists used this sort of time scale? Then people would see all the hype is actually just normal fluctuations in the environment. Unless of course if you manipulate the data to hide the "inconvenient truth."

[Viking12]

5. How about the last 2000 years, globally represented?

Edit: Source http://www.nap.edu/catalog.php?record_id=11676

[guardian]

6. A good graph ...

but your scale on the y axis is still too coarse. Come on! tenths of a degree? you can do better than that. This hardly shows anything. I recommend using pico-degrees then the magnitude of change will look realllllllly scary.

[guardian]

7. Here's evidence that somebody is doing it right

See you need to get the graph that these people saw. You'll never be able to convince people of impending doom with just a few tenths of a degree change.


http://www.telegraph.co.uk/news/worldnews/southamerica/argentina/7344329/Baby-survives-parents-global-warming-suicide-pact.html

Francisco Lotero, 56, and Miriam Coletti, 23, shot their daughter and her toddler brother before killing themselves.
Their son Francisco, two, died instantly after being hit in the back. Her parents said they feared the effects of global warming in a suicide note discovered by police.

[joshcryer]

9. The GISP2 ice core was drilled in 1993.

http://maps.google.com/maps?ll=65,-43&spn=0.3,0.3&t=h&q=65,-43">The relative location of the ice core has experienced substantial melting:



You could not drill a GISP3 in the same location and get the same results. Also, GISP2 has no data for the last 100 years or so.

Greenland is likely far beyond any of these warming periods.

[Statistical]

13. You sure about that I thought average temperature durring ME warm period was 3 degrees higher?

On edit: I guess not. It was warmest period prior to 20th century.

http://en.wikipedia.org/wiki/Medieval_Warm_Period

[joshcryer]

20. We now know that MWP was a localized effect in the northern hemisphere.

MWP did not cover the globe.

[guardian]

29. Let me get this straight

500 years of the MWP in the entire northern hemisphere proves nothing. But "Hottest Summer Ever Recorded For W. Australia; Perth Endures Driest Summer On Record" is proof of AGW.


........right


May I have another glass of more Slammin' Strawberry Kiwi? Just how high of a BKC (i.e., Blood Kool-Aid Content) do you need to have to be to a doomer?

[FBaggins]

31. We "know" no such thing

We speculate that this may be the case... but it is by no means an established fact.

[muriel_volestrangler]

30. So, what are the current conditions?

We've established this graph is for temperatures from before 1900 or so. What has happened since?

The closest temperature station I can find that has been going for the past 100 years is this one: http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=431043600000&data_set=1&num_neighbors=1

(other possible candidates here: http://data.giss.nasa.gov/cgi-bin/gistemp/findstation.py?datatype=gistemp&data_set=1&name=&world_map.x=289&world_map.y=41 )

At a rough guess, I'd say that shows an increase of about 2 degrees - back up to the 'Roman warming' level. And I don't think there's an increase of 2 degrees in 100 years anywhere on that graph.

So, the context for the present seems to be "unprecedently fast warming, that has so far warmed the Greenland climate to significantly warmer than it was in the Medieval Warm Period".

[joshcryer]

33. Excellent find. Would be interesting to plot that on to the original.

Way above MWP.

[jman0]

34. It's from a GW Denier site

check it out http://joannenova.com.au/2010/02/the-big-picture-65-million-years-of-temperature-swings/

Original source is David Lappi, a geologist that works for an unnamed petroleum company in Alaska.

[Viking12]

35. That has been pointed out....

along with the facts that ) the ice core data set does not include anything from the last 100 years, and b) one 8" hole in Greenland does not represent global temperatures. Despite that information, the graph still puts "current conditions in historical context" according to the denier(s).