2011-06-14 08:50:00CO2 Currently Rising Faster Than The PETM Extinction Event
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.120.29

Blog post here

2011-06-14 09:11:56
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

Looks good, I went in and made the usual minor editorial changes.  It might be worth bringing up the high sensitivity implications a bit earlier in the post.  Is there any effort to quantify sensitivity in the paper?  Tough to do with the data available, I'm sure.

2011-06-14 09:12:40
MartinS

mstolpe@student.ethz...
129.132.208.188

Thanks for that, well written!

A truly colossal amount of CO2 must have found its way into the atmosphere to create the observed 2–4% fall in carbon-13 isotopes

Should be permille nor percent.

2011-06-14 09:18:49
MartinS

mstolpe@student.ethz...
129.132.208.188

@Dana: 2009 Zeebe et al concluded that a sensitivity of 3°C is not enough to explain the observed temperature rise with their model (3000 GtC release as methane: CO2 rise from 1000 ppm to 1700 ppm)

 

2011-06-14 09:56:26
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.98.205

"Should be permille nor percent."

Thanks Martin, I have omitted it now - for simplicity's sake. 

2011-06-14 10:12:45
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.98.205

Dana, I didn't want to delve into sensitivity, aside from a mention at the end. The paper provided by Martin, and a couple of others IIRC, do discuss it. Maybe the subject of a seperate post?

I'm going to write one about the huge seasonal flooding in Spain - which accompanied the PETM warming. Lends support to Wally Broecker's analogy of the climate being a "onery beast over-reacting to the slightest nudge"   

2011-06-14 13:57:46
Andy S

skucea@telus...
66.183.170.32

Surface waters were not affected by ocean acidification during the PETM and, unlike other cores which can be highly compacted, ...

I'm not sure this is correct (but I haven't read the Cui paper since I don't subsctribe). From what I understand from the abstract and the press release, the deep sea records are suspect because the organic CaCO3 dissolved partly or mostly in the acidic seawater because the small critters' exoskeletons were in contact with the water for a long time as they slowly sank to the seabed. In contrast, in the shallow marine sedimentary environment in Svalbard, deposition of the organic carbonate was much more rapid and it was less likely to have been dissolved, because the material was exposed to seawater for a shorter time period. I don't think there's any reason to think that the shallow seawater was less acid. Please don't take this as gospel.

One niggle: the word "compacted" has a specific meaning in sedimentology (it's related to burial and loss of pore space) and the Svalbard sediments may actually have been compacted more than the deep-sea sediments. A better word would be "condensed", since people often tak of a condensed section, being one with a long time span over a small sedimentary thickness.

Otherwise, very good indeed.

By the way, for part 2, there's a good review on the PETM here. Very handy for comparing the various studies, which frequently disagree significantly on the amount of carbon injected during the PETM.

2011-06-14 19:50:39
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.4.254

Andy, thanks. I didn't realize that compacted had a specific geological meaning, I've changed the wording to condensed (that's the word used in papers anyway).

Shoaling of the CCD (calcite compensation depth) affected the deep sea sediments, but many sediments are also highly condensed, the it's just a reflection of the rate of sedimentation at each site. The rate of sedimentation at the coastal site is many times higher than the open ocean (such as the Sth Atlantic drill site examined by Kennett & Stott).

As for surface waters, I haven't found studies that categorically state surface waters acidified to any great extent - certainly nothing like what is happening today. I've read a fair bit of Kump & Ridgewell's (two of the co-authors) work and in papers as recent as last year - they find no convincing evidence of surface acidification during the PETM. And the last link in the post cites a paper by Ridgewell & Schmidt, where they model both the PETM and modern day acidification - which supports the notion that the PETM had a limited effect on surface waters. Great treatment of the topic in Ocean Acidification in Deep Time - Kump 2010.

Doug Mackie & co have an upcoming series on OA I'm looking foward to, which will be a great help in reducing some of the confusion -for me at least! 

Having said all that, I've removed the offending text anyway, not important for this post methinks.

2011-06-15 02:46:02
Andy S

skucea@telus...
66.183.170.32

Rob, oddly enough I read the Kump 2010 paper last night after posting my comment and realized that I hadn't grasped the CCD point very well at all. It's the pressure dependency of calcium carbonate solution with depth (and the dissolution of the forams etc on the deep sea bed) that's more important than the rapid burial that I initially thought. 

I have to say that my understanding of ocean chemistry is pretty weak and I look forward to Doug Mackie's series.

2011-06-16 01:12:10
dana1981
Dana Nuccitelli
dana1981@yahoo...
69.230.102.37

Let me know when you're ready to publish this one, Rob.

2011-06-16 03:58:51Hansens's take on the PETM
John Hartz
John Hartz
john.hartz@hotmail...
99.95.221.238

James Hansen addresses the PETM in detail on Pages 161-164 of "Storms of My Grandchildren." You may want to include a reference to this in your article. 

2011-06-16 08:03:47
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.121.49

Badger - thanks, but I haven't read Hansen's book. I have no idea what he says about the PETM. I did, however, go to a talk he gave a couple of weeks back in Auckland, NZ. Didn't talk about the PETM.

Dana - Good to go. Cheers.

2011-06-16 08:06:57
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

Okay, I'll plan on posting this one tomorrow morning Rob.

2011-06-16 13:33:25
Alex C

coultera@umich...
67.149.101.148

You bring up the coefficient figure that links the modeled mass methane emissions from then to current CO2 emissions, but since methane's GWP potential is much higher than CO2's, would that statement need any sort of mentioning of this effect?

Looks good otherwise.

2011-06-16 20:42:28
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.114.120

Alex, good catch, just clumsy wording on my part - now rectified. Both are CO2 equivalents.  

2011-06-16 23:59:45
James Wight

jameswight@southernphone.com...
121.79.14.102

I have Hansen’s book. He makes the following points:

  • The carbon released was about 3,000 Gt, approximately equal to the total of today’s coal, oil, and gas reserves.
  • Because of the current cold climate, the methane hydrate “gun” is now more loaded than it was during the PETM – perhaps as much as 5,000 Gt.
  • The release of the methane hydrates appears to have been a feedback on astronomical forcing.
  • We could set off the same feedback, creating a PETM-like warming on top of the fossil fuel warming.
  • CO2 rose from 1,000 to 1,700 ppm, yet the Earth warmed 5-9°C, suggesting a very high climate sensitivity.
  • The recovery via the negative weathering feedback took 100,000 years. This negative feedback won’t save us.

Hansen concludes runaway warming would occur and the Earth would become like Venus – a bit of a leap, but these facts are certainly cause for concern.

2011-06-17 07:42:50
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.125.182

James, a couple of things:

- The PETM doesn't appear to be tied to any astronomical change, whereas all the Eocene hyperthermals are. It's the odd one out.

- There was a rapid drawdown of CO2 after the end of the CO2 pulse - what the heck caused that? A suggested rapid increase in productivity of the surface ocean (CO2 drawdown by biological activity) has proved a bust (Torfstein 2010).

Thanks for the info.

2011-06-17 08:47:57
Alex C

coultera@umich...
67.149.101.148

Rob - I recall a video Peter Sinclair put up a while ago, a copy of a presentation given by James Hansen in which Hansen brings up the collision of the Indian continent with Asia.  This would have led to a massive upheaval of land (well, it did - the Himalayas), which would provide a larger source for weathering from CO2.  This could have played an important role in the drawdown.  I don't have a paper to reference for you, but here's the video if you'd like.

2011-06-18 10:38:50Commenter jerryd = Gerald Dickson of Dickson 2009 fame
John Cook

john@skepticalscience...
121.222.9.229
Jerryd who commented on the PETM post and is the guy who drew Figure 1 from the post. He offered in a follow up comment to send us more info so I'm emailing him now inviting him to write a guest post.
2011-06-18 19:11:28
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.2.177

Very Cool JC, Dickens has authored/co-authored a stackload of papers on the PETM. 

2011-06-19 22:24:47
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.115.90

JC, see Jerry Dickens comment here. He's got a new paper coming out he's willing to share with us.