I recently posted a guest commentary on RealClimate showing how the graphs Lord Monckton commonly uses to discredit the IPCC’s “predictions” of CO2 and temperature evolution actually use false data. I wasn’t the first scientist to point this out to Monckton, so I didn’t expect him to stop misrepresenting the IPCC. For the most part, Monckton responded to my piece (and a related post by Tamino) with more misrepresentations and lame excuses, but in one case he actually tried to make it appear that he was making a small concession! This would be totally out of character for him, so color me suspicious. In this post I’ll quickly run through his “responses” and then make a BOLD PREDICTION about how his “concession” will play out.
1. I criticized Monckton for saying that the A2 emissions scenario is the IPCC’s “prediction” of how atmospheric CO2 concentration will evolve. The fact is that this depends largely on what humans do, so there’s no way for the IPCC to “predict” that. Instead, they have created SEVERAL “emissions scenarios” to model what might happen if we follow different paths. To choose one of these scenarios as the IPCC’s “prediction” is patently dishonest.
Monckton didn’t really answer this charge in his formal response, but in a comment on my post he said,
The zones of prediction on our graph and on that of the IPCC for the A2 scenario (excepting only differences in the aspect-ratio) are manifestly near-identical. We do not propose to engage in semantic quibbles about whether the word “projection” would be better than the word “prediction” when describing the IPCC’s predictions: the captions on our graphs make it sufficiently clear that the basis of our graphs is the IPCC’s A2 emissions scenario, which we reasonably use because it is closest to actual emissions over recent years.
Supposing the atmospheric CO2 concentration were diverging from the A2 scenario, it would be getting closer to some other IPCC scenario. Since all the scenarios are just hypothetical examples of different ways the situation might play out, it is still dishonest to put up the A2 scenario as the “prediction” of the IPCC.
2. I criticized Monckton because his graph of CO2 evolution under the A2 scenario is wrong everywhere but at the endpoints. In other words, he plotted the A2 scenario incorrectly and then compared his incorrect plot to the real data.
Again, Monckton simply restated his original argument.
On emissions reduction, the international community has talked the talk, but – not least because China, India, Indonesia, Russia, Brazil, and South Africa are growing so quickly – it has not walked the walk. Accordingly, carbon emissions are at the high end of the IPCC’s projections, close to the A2 (“business as usual”) emissions scenario, which projects that atmospheric CO2 will grow at an exponential rate between now and 2100 in the absence of global cuts in emissions… On the A2 emissions scenario, the IPCC foresees CO2 rising from a measured 368 ppmv in 2000 (NOAA global CO2 dataset) to a projected 836[730, 1020] ppmv by 2100.
In the middle of that discussion, he put the following figure:
The argument (if it can be called that) seems to be that Monckton’s graphs of the A2 scenario for CO2 evolution look a lot like that, and the endpoints at the year 2100 are in the right place. In other words, he hasn’t addressed the criticism at all.
Just to emphasize my point, I have taken Monckton’s version of the IPCC figure, digitized it, and plotted the global annual mean atmospheric CO2 concentration, taken from NOAA, on top. The little red dots are the real data.
Did you notice how the little red dots (the real data) lie right on top of the A2 projections, so far? And yet, Monckton is still claiming that his graph (see below), where the real data falls outside of his fake IPCC projection band, is an adequate representation of what the IPCC said!
3. I criticized Monckton because he used a mere 10 years of data to calculate a trend in atmospheric CO2 concentration and pronounce that it is no longer rising exponentially!
4. Finally, I criticized Monckton because he took his fake A2 scenario CO2 numbers and put them through the IPCC’s equation for calculating EQUILIBRIUM temperature response to CO2 forcing, and then plotting the results as a time-series. If he wanted to show the IPCC’s time-series temperature projections under the A2 scenario, what he should have done is plot the TRANSIENT model temperature response, which the IPCC has kindly provided for him.
Monckton admits that transient response is what he really should have plotted, but he now claims (without any real evidence) that the IPCC has monkeyed with their climate models to dampen the transient temperature response in the near-term.
Some have said that the IPCC projection zone on our graphs should show exactly the values that the IPCC actually projects for the A2 scenario. However, as will soon become apparent, the IPCC’s “global-warming” projections for the early part of the present century appear to have been, in effect, artificially detuned to conform more closely to observation. In compiling our graphs, we decided not merely to accept the IPCC’s projections as being a true representation of the warming that using the IPCC’s own methods for determining climate sensitivity would lead us to expect, but to establish just how much warming the use of the IPCC’s methods would predict, and to take that warming as the basis for the definition of the IPCC projection zone.
Yep, we can’t trust the IPCC to tell us what its models predict for transient warming. And yet, Monckton has apparently made a small concession about this issue!
We have made one adjustment to please our critics: the IPCC projection zone in the SPPI temperature graphs now shows transient rather than equilibrium warming.
Really? And exactly how is he going to do that, if you can’t trust the IPCC to tell you what the transient model responses are for its own models? Is he going to run some AOGCMs on his laptop? That might take quite a while, given the computational expense.
Which brings me to my…
BOLD MONCKTON PREDICTION
The idea that Lord Monckton might actually pluck the transient warming projections from a convenient IPCC graph, or that he might run some climate models himself, seems (ahem)… unlikely. So how will he follow through on his promise to plot transient temperature response, rather than equilibrium response? He may have given us a clue in this passage:
Let us illustrate the problem with a concrete example. On the A2 scenario, the IPCC projects a warming of 0.2 K/decade for 2000-2020. However, given the IPCC’s projection that CO2 concentration will grow exponentially from 368 ppmv in 2000 towards 836 ppmv by 2100, CO2 should have been 368e(10/100) ln(836/368) = 399.5 ppmv in 2010, and equilibrium warming should thus have been 4.7 ln(399.5/368) = 0.39 K, which we reduce by one-fifth to yield transient warming of 0.31 K, more than half as much again as the IPCC’s 0.2 K.
Ah, I see. All you have to do to convert equilibrium to transient model response is to multiply by 0.8!!!
Therefore, I BOLDLY PREDICT that if Monckton changes the graphs in his Monthly CO2 Report at all, he will merely multiply his equilibrium calculations by something like 0.8. He will still use the same fake CO2 data to make those calculations, however. And even though he is using different CO2 data and a different method for calculating transient temperature response (a simple, jury-rigged equation vs. running actual climate models) he will still claim that he is using “the IPCC’s own methods”.
In other words, I predict that Lord Monckton will not have reformed at all. Ok, so maybe it isn’t such a bold prediction.
[UPDATE: I should have mentioned that Monckton's final paragraph starts out like this:
One should not ignore the elephant in the room. Our CO2 graph shows one elephant: the failure of CO2 concentration over the past decade to follow the high trajectory projected by the IPCC on the basis of global emissions similar to today’s. As far as we can discover, no one but SPPI has pointed out this phenomenon.
Could it be that NOBODY else has pointed it out because Monckton has plotted the data incorrectly?
The rest of the paragraph says this:
Our temperature graph shows another elephant: the 30-year warming trend – long enough to matter – is again well below what the IPCC’s methods would project. If either situation changes, followers of our monthly graphs will be among the first to know. As they say at Fox News, “We report: you decide.”
And yet, Monckton has clearly indicated that he HAS NOT used "the IPCC's methods."]
[ANOTHER UPDATE: See the comment by Brad Beeson (about the fourth one down) and my reply below. It turns out that Monckton's guesstimation method for getting the transient model response from the equilibrium response might actually work if Monckton didn't insist on using fake numbers for the CO2 concentration.]