Last week an essay — Why I Am A Climate Realist — by NZ CSC “science advisor” Dr Willem de Lange started popping up all over the crank web. I first spotted it at Muriel Newman’s NZ CPR site, and it has since appeared at Monckton’s US lair (complete with a pretty cover). De Lange, a senior lecturer in the Dept of Earth & Ocean Sciences at Waikato Unversity, has not had many starring roles as a climate crank — his biggest claim to fame was a place on the panel discussion after Prime’s showing of The Great Global Warming Swindle last year. But this time he has really stuck his neck out, channelling Wishart’s delusions in this sentence:
It is more likely that the warming of the oceans since the Little Ice Age is a major contributor to the observed increase in CO2.
To show just how wrong he is, I asked Doug Mackie, who is a researcher in chemical oceanography at the University of Otago and regular commenter here, to point out the flaws in de Lange’s essay. Over to Doug:
When Gareth invited me to write a guest post about Willem de Lange’s Why I am a climate realist I knew it was going to be hard. Most of the article is wibble and he really only makes 2 serious points:
– About sea level
-The oceans as the main source of CO2.
(*) Katherine Mansfield, The Advanced Lady.
What has sea level actually done so far this century? There have been large regional variations, but the global rate has slowed and is currently negative, consistent with measured ocean cooling.
This is just another version of Bob Carter’s “not since 1998″ big lie. Just lines above in his article de Lange clearly states that [New Zealand] sea level rises of 0.18 mm y-1 in the 1980’s, 0.17 mm y-1 in 1990 and 0.16 mm y-1 “were not enough to prove that sea level rise was slowing. However, they clearly did not show that sea level rise was accelerating.” And then a few lines later he says the rate has slowed and is currently negative.
It is irresponsible to try using less than a decades worth of data to say anything sensible about global changes in sea level or sea temperature this century. Yes, there have been a minor wiggles in heat content – as we would expect with any real world system — but, as with Bob’s graphs, if you step back and look over a longer term, see AR4WG1 Figure 5.1) or this figure it simply shows small interdecadal variability is imposed over a strong upward trend; see Section 188.8.131.52).
It is more likely that the warming of the oceans since the Little Ice Age is a major contributor to the observed increase in CO2
Actually, temperature has only a small effect on pCO2 (I can come back to this in a dedicated post if there is sufficient interest but it is worth noting that this is basic chemistry and physics). We can be confident the extra CO2 in the atmosphere has come from the oxidation of fossil fuels and has not come from outgassing from the ocean or from soil/land sources by using two key observations.
1) Oxygen decrease
Atmospheric oxygen is going down by the same amount as atmospheric CO2 is going up. Oxygen is so abundant at about 21% (209,500 ppm) that we are in no danger of running out; the change in oxygen simply shows that whatever the source of CO2 in the atmosphere, the carbon part of it has come from the oxidation of reduced carbon compounds and the oxygen has come from oxygen gas in the atmosphere. That is, the extra CO2 was not released in the form of CO2 from an unknown source but instead some reduced carbon compound was burnt in the atmosphere to produce CO2. See: AR3WG1 Section 3.5.1, especially Figure 3.4.
2) Known fossil fuel CO2 emissions.
Most obviously, any alternative explanation for the source of the CO2 in the atmosphere has to also come up with where the 30 billion tonnes of CO2 known to be released by fossil fuel burning each year goes.
Atmospheric CO2 is currently increasing at about 2 ppmv per year (or 16 billion tonnes). That is, only around half of the CO2 we release remains in the atmosphere. The pH decrease in the oceans corresponds to most of the “missing” CO2, so we can also be confident that land use changes etc are not a major source/sink. Caveat: Land use and biomass changes certainly soak up a lot of CO2, some it simply regrowth of forests etc, but the point is that the increasing CO2 in the atmosphere clearly demonstrates that they do not soak up enough.
In summary: (amount of increased CO2 in the atmosphere + the amount of increased CO2 in the oceans) = (amount of known fossil fuel emissions of CO2).
Carbon isotopic ratios indicate that while there is a contribution from the burning of fossil fuels, it is of the order 1-5 percent of the increase.
At first this made no sense to me. Measurements show the ratio of 13C to 12C in atmospheric CO2 is decreasing while the overall total amount of CO2 is increasing.
Photosynthesis strongly favours 12C over 13C. Thus biomass-carbon (including fossil fuels) is depleted in 13C. For inorganic processes, like the way in which CO2 dissolves into the ocean or is degassed from the ocean, does not involve a significant degree of fractionation. Thus ocean-carbon is not depleted in 13C.
Thus, regardless of the total amount of CO2 in the atmosphere, the amount of 12C is going up as a proportion of the total. Therefore some of the extra CO2 in the atmosphere has come from a source that is depleted in 13C, i.e. fossil-carbon. AR3WG1 Box 3.6 . And it was this “some” that gave me the clue.
The answer is that de Lange does not seem to understand about residence times and mixing. This is surprising because it is about as fundamental a concept you get in environmental chemistry and I would expect a coastal oceanographer to use it on a daily basis (e.g. when thinking about tides).
Calculating the amount of fossil fuel CO2 in the atmosphere purely from a change in the isotope ratio is not trivial (but really ought to be within the abilities of any oceanographer). This is because there is constant natural exchange between the atmosphere, the oceans and the terrestrial biosphere (plants and soil). For example, the famous saw-toothing of the Keeling Curve shows the annual uptake and release of atmospheric CO2 by Northern Hemisphere plants. (There is also a SH effect but as the NH has way more land the effect is more obvious).
Look at AR3WG1 Figure 3.1 . It shows the sizes of each pool and the fluxes between each pool. The oceans contain something like 38,000 Pg of carbon (1 Pg = 1 billion tonnes), the atmosphere about 730 Pg C and the land 2,000 Pg C. However, the natural flux (or exchange) between the atmosphere and the oceans is about 90 Pg C y-1 and between the atmosphere and the land the flux is 120 Pg C y-1. This means that each year 230/730 = 32% of the total CO2 in the atmosphere is exchanged with other reservoirs.
A vital point to note is that it is not the exact same carbon atoms taken up and released (i.e. if they all had serial numbers it would be different ones taken up and released). Thus, the natural flux means that though the total CO2 in the atmosphere is increasing, many of the original fossil carbon atoms released to the atmosphere have been swapped and are now in the ocean or in soils/plants. It is the increase in total CO2 that matters in terms of the radiative balance of the atmosphere, not the exact serial number on each carbon atom. The points above demonstrate how we know the extra CO2 comes from fossil fuels.
I haven’t done the numbers (but I could do so running a tweak of Wally Broecker’s Pandora model) so it might be technically true (in a Bill Clinton sense) to suggest 1-5% of the individual carbon atoms in the atmosphere at any one time are the exact same carbon atoms released by fossil fuel burning. But it really shows a truly surprising lack of understanding about residence times, fluxes and perturbations to those fluxes.
Disclosure: Doug Mackie receives funding from the Illuminati of the One World Government, its puppet governments and corporations and has a strong political affiliation (was once party president) to the McGillicuddy Serious Party. I am also a researcher (chemical oceanography) at the University of Otago.