2011-03-30 05:39:33Crux of a Core 3
Rob Honeycutt

robhon@mac...
98.207.62.223

Ah yes, just when you thought is was all over...

I've just created this post in response to a chart showing GISP2 data with the modern instrumental data appended that shows up on the Climate4you website.

I'm waiting for a response from Dr Humlum to see if he intends to update the chart on his site as he said he would.  I may have to include a bit about that or change the post around altogether depending on how he responds.

But this is what I have for the moment.

2011-03-30 05:56:08Rob's storytelling powers deepen, now he dips into Greek myth
John Cook

john@skepticalscience...
124.185.238.238

Have you done any Shakespearean posts yet, Rob? :-)

Anyway, great post. Interesting intro, compelling story, clear science. I did wonder about whether to mention climate lag - that the temperature response to all that rise in CO2 is not fully realised, but meh, keep it simple, stick to your take-home message.

The repetitiveness of coming back to the core is, I think, a good thing - you need to reinforce these points both to increase understanding and simply to get it through people's thick skulls.

2011-03-30 06:01:42
Rob Honeycutt

robhon@mac...
98.207.62.223

"Alas, poor Tuvalu.  I knew him well."  ;-)

Thanks John!  

The first time I emailed Dr. Humlum he responded within 24 hrs.  I'd like to give him a little time to respond before going live with this.  

I'll keep you updated.

2011-03-30 06:15:08
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.194.2

A boulder on your shoulder eh?  I like it. 

2011-03-30 06:22:33thumb
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

Nice improvement on Figure 3, it's much clearer now.

Thumbs-up from me, pending response from Humlum (I like that name, btw).

2011-03-30 07:06:01When you're ready to publish
John Cook

john@skepticalscience...
124.185.238.238

Just give me a nudge in the "Blog posts for this week..." thread and I'll push it up from Pending to the next available slot.

2011-03-30 07:22:16
Rob Honeycutt

robhon@mac...
98.207.62.223

Response from Dr. Humlum...

Dear Rob

I actually updated the graph shortly after your previous mail. Perhaps you are accessing the old version which might still be sitting on some servers? I know that this happens from time to time.

I corrected the red graph addition to indicate an aproximate global post 1850 temperature increase of about 0.75 C, and an aproximate Greenland Ice Sheet temperature increase of about 1.5 C. As I read Box et al. 2009, they suggest a post 1850 temperature increase of about 1-1.5 C (Fig.14).

Best wishes,
Ole

Errr... It looks to me likes he's doing a bit of cherry picking.  The GISP2 data ends at 1855, not 1850.  If you look at the chart on Box's website there is a peak in temp at 1850, then it falls again about 0.5C.  Eyeballing it, to me it looks more like a 2C rise in temp since 1855.

Also, his new graph is still not showing up for me.  Can others try accessing his site and see what comes up?

Thanks!

2011-03-30 07:23:40
Rob Honeycutt

robhon@mac...
98.207.62.223

And does anyone have a copy of Box 2009?  Greenland Ice Sheet Surface Air Temperature Variability: 1840–2007

2011-03-30 08:00:28Climate4You
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

This is the graph I see:

C4U

 

Here's Box 2009.  The graph isn't updated, but he does seem to be right about Greenland temps warming 1 to 1.5°C since 1850.  Although on Box's website, it looks more like 1.5 to 2°C.  So 1.5°C is probably reasonable.

2011-03-30 08:12:28
MartinS

mstolpe@student.ethz...
80.218.206.88

@Rob: Try this: http://polarmet.osu.edu/PolarMet/PMGFulldocs/box_yang_jc_2009.pdf

cyborg was faster ;-)

2011-03-30 08:30:31Comment
Robert Way

robert_way19@hotmail...
134.153.163.105

From NCEP reanalysis 2010 was 2.6 degrees above the 1951-1980 average and a full 1.2 degrees warmer than 2007... Not sure if this helps or not but I think the number for 2010 should be about 3 degrees warmer than 1855 (ish)

http://climexp.knmi.nl/data/inair_298-350E_59-90N_n_su_mean119511980a.txt

2011-03-30 08:36:35
Rob Honeycutt

robhon@mac...
98.207.62.223

It's interesting.  I think he HAS changed the chart to represent a 1C change relative to the left side scale.

There is also a fairly significant difference between Box 2009 and the latest chart on Box's website.

I'm going to email Dr Box and see what he has to say...

2011-03-30 08:36:48Comment
Robert Way

robert_way19@hotmail...
134.153.163.105

NASA data covering 1880-2010 (see link) puts a similar number for 2010
http://climexp.knmi.nl/data/igiss_temp_1200_298-350E_59-90N_n_mean119511980a.txt

note the region covered is not exact...

http://climexp.knmi.nl/plotfield.cgi

2011-03-30 08:48:40
Rob Honeycutt

robhon@mac...
98.207.62.223

Robert...  Yeah, I think the 3C data is correct as the current temps for Greenland.  That's going to look quite a bit different than Humlum's little dotted line.  But I not sure if it's quite right to append 3C on the end of GISP2.  Do you think?

2011-03-30 08:56:34
Rob Honeycutt

robhon@mac...
98.207.62.223

Here's what 3C looks like...

2011-03-30 09:09:23iffy
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

The past few years (not included in Box 2007, obviously) have been hot, but I don't think it's kosher to just use the 2010 temperature.  That's kind of a cherrypick. 

The average over the past decade is about 1.3°C, using Robert's data.  Call 1850 around -0.7°C, and you can say there's a 2°C warming.

2011-03-30 09:13:54
Rob Honeycutt

robhon@mac...
98.207.62.223

Dana...  Yeah, that's about what I'm thinking.  I've made some changes to the post.  If Dr Box responds I might tweak it just a bit more.

2011-03-30 09:16:35confused
MartinS

mstolpe@student.ethz...
80.218.206.88

I am a bit confused: When I searched for GISP2 ice core record I found this page: http://depts.washington.edu/qil/datasets/gisp2_main.html According to that page there is deltaO18 data up to 1987 Is it not possible to use this data? Or what's the point I am failing to see?

2011-03-30 09:26:052010 temp
John Cook

john@skepticalscience...
124.185.238.238

I'd go with Dana's recommendation re using the last decade average but I would also mention 2010 being anomalously hot, explaining why you don't use it. Demonstrates you're taking a measured approach.

2011-03-30 09:27:50
Rob Honeycutt

robhon@mac...
98.207.62.223

Martin...  I believe this is the data that people usually use for GISP2 temperature data.  Alley 2000.

2011-03-30 09:35:51Two different scales
John Cook

john@skepticalscience...
124.185.238.238

Why does Humlum's left Y-axis have a different scale to the right Y-axis? It's twice the scale.

2011-03-30 09:40:35
Rob Honeycutt

robhon@mac...
98.207.62.223

There is a note there that says "approximate global temperature anomaly."  I'm not sure how he's trying to calculate that.  I'm sure there is some method that he's applying.

2011-03-30 09:56:14scales
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

It appears that he's assuming Greenland temperature changes are twice as large as average global temperature changes.  Given polar amplification, that's probably reasonable.  I recall Hansen saying something similar.

I like John's suggestion to mention that 2010 was even hotter than the average over the last decade.  You could even put a dot with an arrow and '2010' label on there, with the dot about 1°C higher (3°C above 1850).

2011-03-30 10:16:50
Rob Honeycutt

robhon@mac...
98.207.62.223

Okay guys.  Added in the 3C point and a little more verbiage.  

I think she's done.

2011-03-30 10:23:09comment
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

I'd revise this sentence:

"The actual annual Greenland temperature anomaly for 2010 is 3C over above 1855, but this is clearly an anomaly and the 2C figure is a more realistic average the average over the past decade has been approximately 2C above 1855."

 

2011-03-30 10:35:27
Rob Honeycutt

robhon@mac...
98.207.62.223

Got it.

2011-03-30 10:56:18So this is ready to go?
John Cook

john@skepticalscience...
124.185.238.238

Shall I add it to the schedule?

2011-03-30 11:08:30
Rob Honeycutt

robhon@mac...
98.207.62.223

Add away, John!

2011-03-30 12:34:36
Alex C

coultera@umich...
67.149.101.148

>>>It appears that he's assuming Greenland temperature changes are twice as large as average global temperature changes.  Given polar amplification, that's probably reasonable.  I recall Hansen saying something similar.

Actually I think that Hansen was referring to Antarctic temps.  Greenland temperatures vary HUGELY, much more so than Antarctic temps.  Hansen 2008 did this with Vostok data (I'm pretty sure it's Vostok, Fig. 1).

Whereas Antarctic temps vary on the order of about 10˚C between glacial periods, the GISP2 data varies about 20˚C.

I don't like though how it seems that he merely scaled it down in the new graph.  The result is NOT an estimated global average, it is the GISP2 data multiplied by a scalar to bring it down to variances that are more in line with what global anomalies would be.  Similar anomaly sizes ≠ similar averages; polar amplification is still obvious, and the poles show antiphase in several cases so my second point would be "Why not use Vostok?"

2011-03-30 12:38:28
Alex C

coultera@umich...
67.149.101.148

However:

<----------

2011-03-31 03:09:01
Rob Honeycutt

robhon@mac...
98.207.62.223

Added one last figure to this piece.  The adjusted EPICA data.