Incredulity, Credulity and the Carbon Cycle

Incredulity, in the face of startling claims, is a natural human reaction and is right and proper.

When I first heard the news about the detection on 14th September 2015 of the gravitational waves from two colliding black holes by the LIGO observatories I was incredulous. Not because I had any reason to disagree with the predictions of Albert Einstein that such waves should exist, rather it was my incredulity that humans had managed to detect such a small change in space-time, much smaller than the size of a proton.

How, I pondered, was the ‘noise’ from random vibrations filtered out? I had to do some studying, and discovered the amazing engineering feats used to isolate this noise.

What is not right and proper is to claim that personal incredulity equates to an error in the claims made. If I perpetuate my incredulity by failing to ask any questions, then it’s I who is culpable.

And if I were to ask questions then simply ignore the answers, and keep repeating my incredulity, who is to blame? If the answers have been sufficient to satisfy everyone skilled in the relevant art, how can a non expert claim to dispute this?

Incredulity is a favoured tactic of many who dispute scientific findings in many areas, and global warming is not immune from the clinically incredulous.

The sadly departed Professor David Mackay gives an example in his book Sustainable Energy Without the Hot Air (available online):

The burning of fossil fuels is the principal reason why CO2 concentrations have gone up. This is a fact, but, hang on: I hear a persistent buzzing noise coming from a bunch of climate-change inactivists. What are they saying? Here’s Dominic Lawson, a columnist from the Independent:  

“The burning of fossil fuels sends about seven gigatons of CO2 per year into the atmosphere, which sounds like a lot. Yet the biosphere and the oceans send about 1900 gigatons and 36000 gigatons of CO2 per year into the atmosphere – … one reason why some of us are sceptical about the emphasis put on the role of human fuel-burning in the greenhouse gas effect. Reducing man-made CO2 emissions is megalomania, exaggerating man’s significance. Politicians can’t change the weather.”

Now I have a lot of time for scepticism, and not everything that sceptics say is a crock of manure – but irresponsible journalism like Dominic Lawson’s deserves a good flushing.

Mackay goes on to explain Lawson’s error:

The first problem with Lawson’s offering is that all three numbers that he mentions (seven, 1900, and 36000) are wrong! The correct numbers are 26, 440, and 330. Leaving these errors to one side, let’s address Lawson’s main point, the relative smallness of man-made emissions. Yes, natural flows of CO2 are larger than the additional flow we switched on 200 years ago when we started burning fossil fuels in earnest. But it is terribly misleading to quantify only the large natural flows into the atmosphere, failing to mention the almost exactly equal flows out of the atmosphere back into the biosphere and the oceans. The point is that these natural flows in and out of the atmosphere have been almost exactly in balance for millenia. So it’s not relevant at all that these natural flows are larger than human emissions. The natural flows cancelled themselves out. So the natural flows, large though they were, left the concentration of CO2 in the atmosphere and ocean constant, over the last few thousand years.

Burning fossil fuels, in contrast, creates a new flow of carbon that, though small, is not cancelled.

I offer this example in some detail as an exemplar of the problem often faced in confronting incredulity.

It is natural that people will often struggle with numbers, especially large abstract sounding numbers. It is easy to get confused when trying to interpret numbers. It does not help that in Dominic Lawson’s case he is ideologically primed to see a ‘gotcha’, where none exists.

Incredulity, such as Lawson’s, is perfectly OK when initially confronting a claim that one is sceptical of; we cannot all be informed on every topic. But why then not pick up the phone, or email a Professor with skills in the particular art, to get them to sort out your confusion?  Or even, read a book, or browse the internet? But of course, Dominic Lawson, like so many others suffers from a syndrome that  many have identified. Charles Darwin noted in The Descent of Man:

“Ignorance more frequently begets confidence than does knowledge: it is those who know little, not those who know much, who so positively assert that this or that problem will never be solved by science.”

It is this failure to display any intellectual curiosity which is unforgivable in those in positions of influence, such as journalists or politicians.

However, the incredulity has a twin brother, its mirror image: credulity. And I want to take an example that also involves the carbon cycle,.

In a politically charged subject, or one where there is a topic close to one’s heart, it is very easy to uncritically accept a piece of evidence or argument. To be, in the technical sense, a victim of confirmation bias.

I have been a vegetarian since 1977, and I like the idea of organic farming, preferably local and fresh. So I have been reading Graham Harvey’s book Grass Fed Nation. I have had the pleasure of meeting Graham, as he was presenting a play he had written which was performed in Stroud. He is a passionate and sincere advocate for his ideas on regenerative farming, and I am sure that much of what he says makes sense to farmers.

The recently reported research from Germany of a 75% decline in insect numbers is deeply worrying, and many are pointing the finger at modern farming and land-use methods.

However, I found something in amongst Harvey’s interesting book that made me incredulous, on the question of carbon.

Harvey presents the argument that, firstly, we can’t do anything to reduce carbon emissions from industry etc., but that secondly, no need to worry because the soils can take up all the annual emissions with ease; and further, that all of extra carbon in the industrial era could be absorbed in soils over coming years.

He relies a lot on Savory’s work, famed for his visionary but contentious TED talk. But he also references other work that makes similar claims.

I would be lying if I said there was not a part of me that wanted this to be true. I was willing it on. But I couldn’t stop myself … I just had to track down the evidence. Being an ex-scientist, I always like to go back to the source, and find a paper, or failing that (because of paywalls), a trusted source that summarises the literature.

Talk about party pooper, but I cannot find any such credible evidence for Harvey’s claim.

I think the error in Harvey’s thinking is to confuse the equilibrium capacity of the soils with their ability to take up more, every year, for decades.

I think it is also a inability to deal with numbers. If you multiply A, B and C together, but then take the highest possible ranges for A, B and C you can easily reach a result which is hugely in error. Overestimate the realistic land that can be addressed; and the carbon dioxide sequestration rate; and the time till saturation/ equilibrium is reached … and it is quite easy to overestimate the product of these by a factor of 100 or more.

Savory is suggesting that over a period of 3 or 4 decades you can draw down the whole of the anthropogenic amount that has accumulated (which is nearly 2000 gigatonnes of carbon dioxide), whereas a realistic assessment (e.g. www.drawdown.org) is suggesting a figure of 14 gigatonnes of carbon dioxide (more than 100 times less) is possible in the 2020-2050 timeframe.

There are many complex processes at work in the whole carbon cycle – the biological, chemical and geological processes covering every kind of cycle, with flows of carbon into and out of the carbon sinks. Despite this complexity, and despite the large flows of carbon (as we saw in the Lawson case), atmospheric levels had remained stable for a long time in the pre-industrial era (at 280 parts per million).  The Earth system as a whole was in equilibrium.

The deep oceans have by far the greatest carbon reservoir, so a ‘plausibility argument’ could go along the lines of: the upper ocean will absorb extra CO2 and then pass it to the deep ocean. Problem solved! But this hope was dashed by Revelle and others in the 1950s, when it was shown that the upper-to-lower ocean processes are really quite slow.

I always come back to the Keeling Curve, which reveals an inexorable rise in CO2 concentrations in the atmosphere since 1958 (and we can extend the curve further back using ice core data). And the additional CO2 humans started to put into the atmosphere since the start of the industrial revolution (mid-19th century, let us say) was not, as far as I can see, magically soaked up by soils in the pre-industrial-farming days of the mid-20th century, when presumably traditional farming methods pertained.

FCRN explored Savory’s methods and claims, and find that despite decades of trying, he has not demonstrated that his methods work.  Savory’s case is very weak, and he ends up (in his exchanges with FCRN) almost discounting science; saying his methods are not susceptible to scientific investigations. A nice cop-out there.

In an attempt to find some science to back himself up, Savory referenced Gattinger, but that doesn’t hold up either. Track down Gattinger et al’s work  and it reveals that soil organic carbon could (on average, with a large spread) capture 0.4GtC/year (nowhere near annual anthropogenic emissions of 10GtC), and if it cannot keep up with annual emissions, forget soaking up the many decades of historical emissions (the 50% of these that persists for a very long time in the atmosphere).

It is interesting what we see here.

An example of ‘incredulity’ from Lawson, who gets carbon flows mixed up with net carbon flow, and an example of ‘credulity’ from Harvey where he puts too much stock in the equilibrium capacity of carbon in the soil, and assumes this means soils can keep soaking up carbon almost without limit. Both seem to struggle with basic arithmetic.

Incredulity in the face of startling claims is a good initial response to startling claims, but should be the starting point for engaging one’s intellectual curiosity, not as a perpetual excuse for confirming one’s bias; a kind of obdurate ignorance.

And neither should hopes invested in the future be a reason for credulous acceptance of claims, however plausible on face value.

It’s boring I know – not letting either one’s hopes or prejudices hold sway – but maths, logic and scientific evidence are the true friends here.

Maths is a great leveller.

 

(c) Richard W. Erskine, 2017