http://hot-topic.co.nz/wp-content/uploads/2011/01/easterbrook_fig5.png

The actual data shows 17 periods warmer than the -30.15 2010 estimate:-

2.00687 – 2.20231
2.32376 – 2.3545
3.13329 – 3.43744
3.60574 – 3.66517
4.25679
4.99637 – 5.02375
5.14763 – 5.21773
5.57743 – 5.68131
6.75923 – 7.00894
7.40322 – 7.48772
7.55658 – 7.57475
7.64267 – 8.02902
8.59735
8.65181
8.68911 – 9.19888
9.30211 – 9.40756
9.67046 – 9.78686

The major periods total 5790 years.

This is being debated at WUWT

http://wattsupwiththat.com/2011/01/24/easterbrook-on-the-magnitude-of-greenland-gisp2-ice-core-data/#comment-583495

GR at HT is still on DE’s case too.

Presentation of “The Primary and Secondary Climate Drivers”, a compilation of papers and articles evidencing solar, lunar, cosmic ray and celestial influence on climate change.

With emphasis on predictive skill.

The age units are thousands of years before present, with “present” defined as 1950 AD. As an aside, many geologic time series are dated via radiocarbon, which is unreliable after 1950 AD due to atmospheric testing of H-bombs, so 1950 AD was adopted as “present” by radiocarbon dating scientists, and adopted in paleoclimatology as well.

The date ranges in the data file are correct. Temperature data extend from 0.095 to 49.981 thousand years before 1950 AD, so the corresponding calendar dates would be 1855AD to -48031 AD. The accumulation data are reported from 0.144 to 49.0034 thousand years before 1950 AD.

Sorry for the date range error on the Alley 2000 web page. We have migrated through several versions of databases with different age scales, and obviously ended up with the wrong age range for this study.
Sincerely, Bruce

Bruce Bauer, Data Manager
World Data Center for Paleoclimatology and
NOAA’s National Climatic Data Center, Paleoclimatology Branch
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This means GR is right and DE should add a 2010 estimate to the 1855 data point on his Fig 5 in order to establish the present for comparison of the last 10,000 years of GISP2.

http://hot-topic.co.nz/wp-content/uploads/2011/01/easterbrook_fig5.png

If Don had added a 2000-2010 temperature estimate to his graph, the baseline rises by just over 1C (1.44 using GRIP) so that “9,100″ reduces to about 4500? above that over the last 10,000 years – still a considerable amount. I am confronting him on this but so far he has been intractable.

Drilling of the GISP2 ice core was completed in 1993, which precludes a top-of-the-core date of 2000. After the drilling, additonal firn studies were made so data may be available to 2000, but it isn’t from the top of the core. 1950 is the date used by ice core researchers as a common starting point, but it’s not the top of the core. If you look at the original oxygen isotope data of Stuiver and Grootes (available at the Univ. of Washington website) you will see that the top of their data set is 1987. Alley’s curve begins at 95 years before 1950 (1855), so CO2 dogmatists are claiming that is the top of core, but that is incorrect. Alley states that “Temperature interpretation based on stable isotope analysis, and ice accumulation data, from the GISP2 ice core, central Greenland. Data are smoothed from original measurements published by Cuffey and Clow (1997).” So, going back to the the Cuffey and Clow curve that Alley’s curve is based on, that curve begins at 0 yrs and they state: “We chose to calibrate the GISP2 δ18O raw data as given by Grootes et al. (1993) and Stuiver et al. (1995),” which clearly starts in 1987. Thus, the Cuffey and Clow curve apparently begins in 1987, not 1950 or 1855. Temperatures in Greenland from 1935 to 1940 were about 1 degree C (1.8 degrees F) warmer than in 2005 (see attached temp curve), so it has not been warmer in Greenland since 1940. The isotope data set of Stuiver and Grootes includes 47 years after 1940, and since it has not been warmer in Greenland since 1940, Greenland has not been warmer than it was at the top of the ice core (1987). If you draw a straight horizontal line from the 0 point (1987) in the Cuffy and Clow curve, all of the Holocene temps are above that line. Alley’s curve is slightly different, showing a few cooler times (e.g., Little Ice Age). The conclusion that more than 9,000 of the past 10,500 years were warmer than present is thus confirmed.

Don
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“(see attached temp curve)” refers to “Greenland temp curve 1880-2004.jpg” that I’m unable to find on the internet but is available from me here rscumming@gmail.com. Both this plot and the GRIP 1840-2009 plot at HT (“Easterbrook’s wrong (again)” post) show the 1940s warming that the CO2 forced models cannot hindcast BTW.

A 1987 start date sets the first data point in the GISP2 temperature reconstruction at 1892 (95 BP 1987) according to Don’s reply.

HT (“Easterbrook’s wrong (again)” post) has this Easterbrook quote from the EIKE forum:-

The contention that the ice core only reaches 1905 is a complete lie (not unusual for AGW people). The top of the core is accurately dated by annual dust layers at 1987. There has been no significant warming from 1987 to the present, so the top of the core is representative of the present day climate in Greenland.

To which Gareth Renowden says:-

Unfortunately for Don, the first data point in the temperature series he’s relying on is not from the “top of the core”, it’s from layers dated to 1855. The reason is straightforward enough — it takes decades for snow to consolidate into ice.

I agree with GR that Don should include an estimate of 2010 (or 1987) temperature on his disputed Fig 5. but GR could be wrong about 1855 being the first data point (possibly 1892).

I’ve thanked Don for his reply and have asked for a comment on the Fig 5 suggestion. Stil waiting for Bruce Bauer’s reply (NOAA).

If you have a contact then I agree it is best to confirm with them than resort to guesswork.

The actual data, referenced in the txt file,clearly shows the first data point at 95 BP (i.e 1855 )

You’ve identified 1950 as P by prior knowledge of the convention I assume because it does not say 1950 explicitly in the txt file. I was not sure that the convention had been followed by GISP2 but I’ve since found part confirmation in “A Note on the Timescales”:-

http://www.ncdc.noaa.gov/paleo/icecore/greenland/summit/document/notetime.htm

A link “Meese/Sowers timescale” on that page leads to

ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/depthage/gisp2age.txt

And the first data is explicitly at 1.5m -38 (yrs BP 1950) i.e. 1988.

I don’t know what the significance of the 2000 date is, if any

2000 is when the coring project starts but the temp reconstruction does not start until coring is 145 yrs down if 1950 is P or 95 yrs down if 2000 is P.

I’m not convinced by your explanation because ice accumulation rate uses the 1950 P convention as clearly shown in the metadata (Paleo_Stop_Date -50 cal yr BP) but Temperature is stated differently (Paleo_Stop_Date 2000 AD). it seems to me that the Paleo_Temporal_Coverage elements are assigning 2 different conventions.

You may be right that they are one and the same but I’m interested to see what the NOAA contact says.

-107175 AD = 109125 cal yr BP

for the start date. My typo

Start = -107175 AD == -107175 AD
Stop = 2000 AD == -50 BP

i.e you can’t assign different meanings to the two elements.

I don’t know what the significance of the 2000 date is, if any. The actual data, referenced in the txt file,clearly shows the first data point at 95 BP (i.e 1855 )

The XML file seems to be an industry standard metadata file.

@Richard T. This may be worth a post. I’m emailing Don Easterbrook to find out his basis for 1905 being his first data point and the NOAA contact Bruce Bauer to ascertain the correct “present” date for GISP2 temperature..
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I’ve tried fact checking the Renowden – Easterbrook dispute over the “present” date of GISP2 temperature data found here:-

ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2_temp_accum_alley2000.txt

Note there are 2 records – 1) Temperature 2) Accumulation rate (m. ice/year)

First data point 0.0951409 x 1000 years before “present” in the temperature record.

Gareth says this:-

The first data point in the file is at 95 years BP, and shown in his graph. In other words, Don presents 1905 as equivalent to the present — a point I emphasised the last time he used this data. However, we were both wrong.

One of the last comments to my “100 years of warming” post suggested that the GISP2 “present” followed a common paleoclimate convention and was actually 1950. This would make 95 years BP 1855 — a full 155 years ago, long before any other global temperature record shows any modern warming. In order to make absolutely sure of my dates, I emailed Richard Alley, and he confirmed that the GISP2 “present” is 1950, and that the most recent temperature in the GISP2 series is therefore 1855.

Richard Alley is the author of a paper referenced on the following NOAA page but the NOAA contact is E-mail: bruce.a.bauer@noaa.gov

Looking at the NOAA page “GISP2 – Temperature Reconstruction and Accumulation Data”

http://www.ncdc.noaa.gov/paleo/metadata/noaa-icecore-2475.html

Start Year: -107175 AD End Year: 2000 AD

Looking at the page “Complete XML Record: noaa-icecore-2475″

http://www.ncdc.noaa.gov/oai/provider?verb=GetRecord&metadataPrefix=dif&identifier=noaa-icecore-2475

Removing XML

Parameters
ISO_Topic_Category Geoscientific Information ISO_Topic_Category
−
Keyword
earth science paleoclimate ice core hydrogen isotopes Temperature
Keyword
−
Keyword
earth science paleoclimate ice core physical properties ice accumulation rate (meters/year)
Keyword

Paleo_Temporal_Coverage
Paleo_Start_Date -107175 AD Paleo_Start_Date
Paleo_Stop_Date 2000 AD Paleo_Stop_Date
Paleo_Temporal_Coverage

Paleo_Temporal_Coverage
Paleo_Start_Date 109125 cal yr BP Paleo_Start_Date
Paleo_Stop_Date -50 cal yr BP Paleo_Stop_Date

I’m not an expert in XML but this seems to indicate that that the “present” date for temperature is 2000 AD and the “present” date for ice accumulation rate (meters/year) is 1950 AD.
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I do think Don’s plot is misleading by presenting 1905 as present instead of adding a value for 2010 but whether Gareth’s use of GRIP data is valid, I don’t know. Using Gareth’s GRIP reasoning for 1905-2000 the difference would be more like 2.44 C instead of the 1.44 C he came up with for 1850-2000 because 1905 was cooler than 1850 on the GRIP plot.