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GG Reality 2008, `carbonate pump'

Dear Dr. Sommerkorn,

I was pleased to find your paper having `Target CO2...' within references (this way I found it),

It's a very good overview of recent advances in knowledge, even if mostly before that Hansen et al breakthrough `Target' paper.

However, I've noticed some items worth a touch perhaps.

On p. 8, the recent contribution of Greenland Ice Sheet to sea level rise should be given perhaps as 10x less, 5 mm instead of 5 cm per decade -- this is the `almost recent' number as I remember it (double the AR4 one). Recent paper, as I see it within one of the Cobenhaven abstracts (http://climatecongress.ku.dk/programme/),
    Sebastian H. Mernild:
    Increased Greenland melt extent 1995-2007
 reports the 2007 rate at 1 mm per year.

IN the last paragraph on that page, fourth row, "increase" should be inserted twice. Global mean temperatures are about 15 degC...

P. 10, 2nd paragraph, is confused as to biological carbon pumps. Calcite or aragonite produced in upper ocean layers does, surprisingly, _add_ CO2 to the atmosphere. I was explained it by a senior chemist just some fifteen years ago. The confusion of this type is an orders of magnitude more subtle version of a claim `forests are vital as producents of oxygen'. The `carbonate pump' is therefore named appropriately `carbonate counter-pump' -- this string submitted to google leads to relevant texts. `Counter' is OK: it pumps CO2 back to the atmosphere (counter to the nowadays action of the `solubility pump' and the always downward pump of `snow' of organic carbon), and this arrow is counter-intuitive (as some carbon falls to the ocean floor, doesn't it...)

Some links explaining it:

   Linkname: The Carbon Cycle and Climate
     URL: http://earthguide.ucsd.edu/virtualmuseum/climatechange1/06_3.shtml

   Linkname: Global C cycle - key points: Ocean C cycle processes
        URL: http://www.geo.arizona.edu/geo4xx/geos478/GC08.OcBGC1.pdf

   Linkname: Coccolithophores and the biological pump : responses to ...
        URL: http://epic.awi.de/Publications/Ros2004a.pdf

   Linkname: WBGU Special Report 2006
        URL: http://www.wbgu.de/wbgu_sn2006_en/wbgu_sn2006_en_voll_4.html

The important message is that no appreciable effects of alteration of this type of transport are expected during the continuing acidification of oceans.

P. 11, 2nd par.: 383 ppm should not be labelled `now'. An instant should be added (of a smoothed curve perhaps, this would correspond to mid-2007). Or a more current value 386 ppm chosen (for the moment of the publication):
   Linkname: Trends in Carbon Dioxide
        URL: http://www.esrl.noaa.gov/gmd/ccgg/trends/

My last wish: your paper and its references are not that large files to be available just as separate pdfs. A single file comprising both these documents would be convenient. With a new name being even shorter than that of the References pdf.

with best regards,
 Jenik Hollan

                                Jan Hollan
              N. Copernicus Observatory and Planetarium in Brno
Kraví hora 2, CZ - 616 00 Brno                        +420 5 41 32 12 87

Lipová 19, 602 00 Brno                                     5 43 23 90 96

               volunteer of the Ecological Institute Veronica
Panská 9, 602 00 Brno, Czechia

e-mail: hollan@ped....cz             http://astro.sci.muni.cz/pub/hollan