A part of my John Everett series – read more: 0/I – II.0 – II.5 – II.75 –  III.0 – III.3 – IV.0 – IV.4 – IV.8 – V – VII – VIII – Full Report 

The last couple posts looked at Dr. Everett’s discussion of the growth rate of carbon dioxide. There’s one other claim in this section which warrants inspection: that a constant airborne fraction is a challenge to projected acidification.

I got the bright idea to sudo rm -rf in my /etc/ and now GIMP is broken. So none of my sweet graphics this episode. Instead here's a diagram of the carbon cycle, courtesy of NASA (click for sauce.) It's just as well. The coolest thing I could think to draw was some pictures of pie. Mmmm pie.

Here’s what he has to say:

The meaning of this information [the supposed leveling off of CO2 growth rate] (and the future of all climate models[)] became VERY cloudy on 31 December 2009 with the ScienceDaily acknowledgment of a paper published by American Geophysical Union and authored by Wolfgang Knorr that shows “No Rise of Atmospheric Carbon Dioxide Fraction in Past 160 Years”, despite the predictions of carbon cycle/climate models3. The implications of this have yet to be assimilated by the modeling community. This does not mean that CO2 proportion is not rising but rather that the proportion not being assimilated has not changed since 1850. Importantly, it means that the rate of CO2 cycling increases as it becomes more concentrated, and does not decrease as assumed in climate models. The rate of projected growth in CO2 appears to be greatly exaggerated.

The first thing that caught my eye was that Dr. Everett rather specifically references a news item about the Knorr paper, instead than the paper itself. I found that a bit odd- it’s the only time he cites a news item rather than a journal article. So I checked his bibliography. The citation for footnote #3 is:

Knorr, Wolf. “No Rise of Atmospheric Carbon Dioxide Fraction in Past 160 Years” Geophysical Research Letters, Vol. 36, L21710, 5 PP., 2009. Available: http://www.agu.org/pubs/crossref/2009/2009GL040613.shtml

However, Knorr’s paper is actually:

Knorr, W. (2009), Is the airborne fraction of anthropogenic CO2 emissions increasing?, Geophys. Res. Lett., 36, L21710, doi:10.1029/2009GL040613.

See what he did there? He replaced the title of Knorr’s paper with the tagline of a news article about the paper. *edit: see below This may well have been a simple clerical error, but the psychological impact of the two are quite different. The title of the original paper suggests that Dr. Knorr is presenting his work on a difficult and open problem. In Everett’s bibliography, the question has been resolved, case closed. Even if the incorrect citation is an honest mistake, I still have to wonder: why reference the news article at all, other than psychological impact of its tagline?

But what about Knorr’s paper- what does it say?

When you burn a tank of gas or a pile of coal, you produce carbon dioxide. And the CO2 doesn’t just disappear once the plume of smoke blows away. Some of it gets absorbed by plants on land (the land fraction, LF), some by the ocean, causing acidification (the oceanic fraction, OF), and the rest remains in the atmosphere, (the airborne fraction, AF) causing climate change. Obviously, understanding where carbon emissions end up is an important part of understanding the climate system. In particular, there have been some studies which suggest that the ocean carbon sinks are becoming saturated- they are losing the ability to pull CO2 out of the air. The airborne fraction is a measure of how much of the carbon we emit remains in the atmosphere. So, when Knorr’s study appeared, the Skuptik Intarblogs lit up with glee– Alarmist predictions of collapsing carbon sinks had been put to rest! Anthropogenic global warming is a lie/religion/conspiracy!

To his credit, Dr. Everett is conscientious to point out that the AF is a fraction of the total emissions; the total amount of carbon in the atmosphere is still rising. But if his position is that predictions of future acidification are overestimates, then it’s hard to see how Knorr’s paper supports him. Acidification is caused by the amount of CO2 dissolved in the ocean, not the fraction of the total carbon that is in the ocean. It’s like pie: the size of a slice of pie depends on the angle it’s cut at (the atmospheric fraction) and the size of the pie (the amount of CO2 emitted). If you keep the angle the same, but you cut up a bigger pie, you still get a bigger slice of pie. Even Everett’s conservative projections entail significant emissions– a bigger carbon pie. As a result, the ocean will continue to absorb bigger slices of the carbon pie, with continued acidification as a result.

*edit: Took another look; the quoted phrase doesn’t appear in news release at all. It does, however, appear as the title of numerous skuptik blogs. Hm…

**edit: My bad; there’s another instance (#24) … but he egregiously misrepresents that one, too, so I don’t feel that guily.