Glaciations might end: silliness at WUWT won’t

Apparently there was nobody available to write the daily silly post at WUWT yesterday, but Anthony Watts capably filled the void.

Watts has been pointed to Archer and Ganopolski (2005), who argue that CO2 emissions of 1000 Gton C could prevent the next glaciation, and 5000 Gton C could prevent glaciations for the next half million years because of the long atmospheric life-time of CO2 emissions. Watts is arguing that this is a good thing. Presumably he thinks we should emit huge amounts of CO2, endure the changing weather patterns, rising sea-levels and ocean acidification that have already begun and will intensify over the next century, to avoid a glaciation that might not commence for millennia. The silly thing is that because of the absorption of CO2 by the oceans and other sinks, emitting a slug of CO2 over the next century, is a very inefficient way to avoid the next glaciation, but a very efficient way to maximise side-effects. Low emissions over millennia would have the same glaciation-preventing power but with minimal side-effects.

However silly the main post, it is almost guaranteed that the comments will be sillier, and this is no exception for the post assumes that CO2 is a greenhouse gas; that it has a long atmospheric residence time; and that climate models can be useful. My favourite comment is from someone who seems to believe that the “p” in pCO2 is analogous to the “p” in pH.

HenryP says:
April 27, 2013 at 11:47 am
pCO2 is the negatve log (10) of the CO2 concentration in water in moles per liter
ppm ((=mg per kg) is not the right dimension for this

Fortunately, someone eventually states correctly that pCO2 is the partial pressure of CO2.

Lubos Motl, who really ought to stick with string theory, reveals his complete lack of understanding of the climate and carbon cycle in his comment:

Lubos Motl says:
April 27, 2013 at 8:31 am
The claims in the paper are completely preposterous. First, even if the CO2 doubling caused (sensitivity) of 2 Celsius degrees, one would need four doublings to get 8 °C to neutralize an ice age – sixteen times larger concentrations of CO2.

This seems to be an attempt to cram as many errors into a sentence as possible. He takes a low, but not implausible, estimate of sensitivity, an absurdly high estimate of glacial-interglacial temperature change (Schmittner et al. (2011) estimated 2.2 °C), and then assumes that all the change is due to CO2, whereas a large fraction of the cooling is due to changes in dust and ice albedo. After this inauspicious start, it does not improve.

But this mistake is negligible relatively to the residence time. We will probably run out of – or stop using fossil fuels – within 300 years or much less. Within two more centuries, a vast majority of the excess CO2 will be reabsorbed again. There’s no way how we could affect temperatures in the future that is as distant as 5,000 years – first moment when a credible sign of a new ice age might potentially occur.

This will be news to the fake sceptics that pronounce the beginning of a new ice age every time one year is colder than the previous.

The excess CO2 above the temperature-dictated equilibrium (now 280 ppm) is decreasing exponentially with time with the halving time currently shorter than a century (it may be a bit longer when life is mostly frozen and slowly reacts to the changes). It’s easy to see why it’s so. We’re emitting the equivalent of 4 ppm of CO2 in the atmosphere every year but the concentration only grows by 2 ppm. So the remaining 2 ppm are absorbed. They are absorbed *because* the CO2 is elevated so the consuming processes are strengthened. They would be strengthened even if we didn’t emit any CO2 because these ocean and life processes don’t care about the emissions in the last year – they only care about the immediate CO2 concentration in their vicinity. So the concentration would begin to drop by 2 ppm a year if we stopped making any emissions tomorrow.

This is simply nonsense — it assumes that there are infinitely large sinks for CO2.


About richard telford

Ecologist with interests in quantitative methods and palaeoenvironments
This entry was posted in Fake climate sceptics, Silliness, WUWT. Bookmark the permalink.

2 Responses to Glaciations might end: silliness at WUWT won’t

  1. KAP says:

    Motl made yet another howler that you missed: it doesn’t take 4 CO2 doublings to get to 8°C under his assumptions, it only takes 3 doublings.

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