Chapter 1 – Ian Plimer
Plimer is a notable Australian geologist who, once upon a time, was a scourge of creationists. Since those heady days, he has morphed into a scourge of climate scientists. His biggest book on the subject, Heaven & Earth, was notable for its numerous errors, which surprisingly included a number of geological ones (e.g. on volcanoes).
In this chapter, Plimer is going to tell us how science works and why climate change science is wrong. I’m always a teeny bit excited opening up an essay like this. You just never know which bits of science the writer will accept and which will be poo-pooed.
Plimer opens with a paragraph of his model of science:
“We derive scientific evidence from measurement, observation, and experiment. Evidence must be repeatable and collected over and over again. Computers do not generate evidence: they analyse evidence that should have been repeated and validated. On the basis of the evidence and analysis of evidence, an explanation is given. This explanation is a scientific theory and must be in accord with other validated evidence from diverse sources (this is known as the coherence criterion in science).Unlike in law, there is no inadmissible evidence in science. Science is underpinned by practitioners who must be sceptical of the methodology used to collect evidence, the analysis of evidence, and the conclusions based on the evidence. On the basis of new evidence, scientists must always be prepared to change their opinions.”
It’s not an unreasonable model. The stuff about computers doesn’t make much sense out of context but he has tacked it in there so he was a critique of computer models. A simple test to see whether a critique of ‘computers’ in science makes sense is to just remember that computers are simply a way of taking the drudgery out of mathematics and mathematical models. Any valid critique of computers in general should still make sense if ‘mathematics’ or ‘mathematical’ is substituted for ‘computer’. “Mathematics does not generate evidence” has a pedantic truth to it but only for a very forced and restricted meaning of evidence. The same is true about computers. In both cases, real world data is needed but mathematical/computer models can generate evidence based on that.
Or consider a theoretical model of something – a bridge for example. The model would have been built using real world data but that data would not necessarily have been specifically about bridges and might be quite distance from the physical theories implemented in the model. If the bridge falls down in the model, Plimer’s view would say that this is NOT evidence that a similar bridge will fall down in real life. Note we are discussing *evidence* not certainty or proof. That view is nonsense. If the model is sound then the person designing the bridge would be wise to reconsider their design. Perhaps Plimer meant something else? Who knows but in any sensible model of evidence that output of a sound computer model is some kind of scientific evidence – not conclusive or infallible but still evidence to some degree.
Plimer then goes on to knock over the consensus straw man. The hypothesis that climate change will occur (and has) occurred because of anthropogenic emissions of greenhouse gases causing global warming is not true BECAUSE there is a consensus among scientists who have studied it but rather that consensus has come about BECAUSE the hypothesis is true *AND* the only reason people keep pointing it out is because the side that disputes this (which Plimer represents) have in the past claimed it was false or in dispute because there wasn’t a consensus. Consensus doesn’t matter? Great – in that case the various petitions, lists, signatories that the denial industry produce are irrelevant and indeed Plimer should be roundly condemning them as bad scientific arguments.
Many Western governments have a politically popular ideology that argues that:
i. There is an increase in emissions of carbon dioxide (CO2) by human activities;
ii. The increased CO2, a greenhouse gas, will lead to ever increasing global warming;
iii. There will be tipping points, sea level rises, extinctions and ocean acidification;
iv. Climate change will be irreversible and that human emissions of CO2 must be reduced or stopped as soon as possible; and
v. In order to stop climate change, energy sources need to be shifted from coal, gas and oil to wind, solar, tidal and biomass.
He then addresses each of these points in turn.
Point i he agrees with and he then extols the virtues of the industrial revolution and finishes with the ‘CO2 is plant food’ line. Which is true. Plants do like CO2, weeds just as much as food crops. Food crops though are sensitive to many environmental conditions.
Point ii is where things get fun.
There is no doubt that CO2 is a greenhouse gas. However, the main greenhouse gas is water vapour.
Phew! We are over one hurdle! Plimer nicely concedes CO2 is a greenhouse gas but then waves his finger at water vapour. He is quite correct that water vapour is a powerful and dominant greenhouse gas. What he avoids mentioning is that water vapour is exactly why extra CO2 is so problematic. The amount of water vapour in the atmosphere is very sensitive to temperature (think about it – think about the range of temperatures in which water is a liquid and evaporates). Increase CO2 and you get a certain amount of warming just from the CO2 but that additional warming means MORE water vapour in the atmosphere as well, which means more warming. This is one of the key feedback effects in global warming. Actually, I can be quite sure Plimer knows this as it is global warming 101 – that he avoids mentioning it is telling. Oh, and those feedback effects are why we need computer models – this isn’t something that you can just work out via debating-society style arguments.
Later (in Chapter 11) Australian blogger Jo Nova gets this point more right than Plimer:
“It seemed like a good idea at the time. Water vapour (aka humidity) is a more powerful greenhouse gas than CO2. Warmer air can hold more water vapour. What if CO2 warmed the world, which caused humidity to rise and amplified the warming? Catastrophe.” [Chapter 11]
Back to Plimer:
“We are also asked to believe that the 32 molecules of CO2 of natural origin in every 85,000 molecules play no part in driving climate change.”
In which Plimer apparently forgets what the word “change” means. ‘Natural’ CO2 certainly plays an important part in global temperatures. Without it the world would be much, much colder. Nobody is asking him to believe otherwise. Indeed this is another case of climatology 101. CO2 is a naturally occurring and important greenhouse gas. This is true whether or not global warming is happening or any political agenda. But the issue at hand is warmING not warmTH. It is the additional CO2 that should (and apparently does) lead to additional warmth.
Again, oddly later in the book the less scientifically literate Nigel Lawson gets this more right than Plimer:
“Without the greenhouse effect, the planet would be so cold as to be uninhabitable. But, by burning fossil fuels— coal, oil and gas— we are increasing the amount of CO2 in the atmosphere and thus, other things being equal, increasing the earth’s temperature.” [Chapter 7]
Meanwhile, Plimer has more straw men to knock over. The next is multiple examples of Earth’s climate changing for reasons other than rising CO2. That would be an excellent refutation of a claim that CO2 is the only thing that can cause climate change of any kind at any time but sadly for Plimer that isn’t a claim anybody sensible is making. Remember that we already know (and Plimer accepts) that CO2 really has risen. This not a case of us observing climate change and guessing at causes.
Finally, he ends his refutation of point ii not with evidence against but a sort of sure-its-true-but-warm-is-nice argument.
“History shows that communities thrived when it was warm and there was massive depopulation during cooler times.”
In reality, Plimer is deeply undermining his own position in the hope that nobody will notice his shotgun technique of throwing any old argument out there. What he presents is that climates can change, that actually climates are relatively sensitive and finally that climate change has impacted human populations significantly.
Point iii is a bit of a mixed bag and it’s unclear what he intends to use as straw men. Possible consequences of global warming are many and the full extent of them can’t be known. Still, having dealt himself a better hand he still plays it poorly.“It seems illogical that the current sea level rise is due to human activities, whereas the previous hundreds of sea level rises were not.”
“It seems illogical that the current sea level rise is due to human activities, whereas the previous hundreds of sea level rises were not.”
No, because firstly the claim isn’t that the only cause of any climate change ever in the existence of the Earth is the current cause of climate change and secondly the capacity for humans to cause a change in the climate is substantially greater than it has ever been.
Plimer’s penultimate point iv wanders into conspiratorial territory. He announces:
“There has never been a public debate about human-induced climate change.”
Which is weird considering he is in the middle of debating it publicly but it is also just flat-out rewriting history: the debate about CO2’s role in the atmosphere and the possibility that burning fossil fuels may cause a net increase in warming has been going on for many decades. This is not a new topic, nor did scientist suddenly just dredge up the idea out of nothing and then enforce some sort of dogma. Debate and investigation took place through out the twentieth century. In the 1970s improved evidence and improved understanding of climate pointed increasingly towards global warming being the most likely outcome but even then there was substantial debate and informed contrary opinion (indeed Plimer’s allies make a big deal of the new ice-age scare of the 1970s). What has occurred since has been the debate shifting from fairly likely to very likely based on a gathering weight of evidence. The debate has been extensive and very public. So why does Plimer pretend that it hasn’t?
Finally, Plimer repeats various standard complaints about renewable energy sources.
Overall, what characterises Plimer’s essay is statements that are easily checked against facts and found wanting or which are misleading and seem grounded in ignorance of the topic.