Oddly, NIWA scientists conceal them
UPDATE 1: 28 Mar 1300 NZDT, see below.
John’s letter refers to the WRR article Human role in climate change is clear. The following are excerpts from the AR5 then the WRR article (emphasis added). Notice the stinging observation that WRR failed to disclose what was inconvenient for the IPCC to say, because it contradicted the alarming sounds of doom.
Wratt, Reisinger and Renwick have all been closely involved with the IPCC so I ponder why their article failed to tell readers exactly what the latest IPCC report said, specifically:
1. “… the rate of warming over the past 15 years (1998–2012; 0.05 [–0.05 to 0.15] °C per decade) … is smaller than the rate calculated since 1951 (1951–2012; 0.12 1 °C per decade).” [SPM, page 3, section B.1, and in full Synthesis Report on page SYR-6]
2. “… an analysis of the full suite of CMIP5 historical simulations (…) reveals that 111 out of 114 realisations show a GMST trend over 1998–2012 that is higher than the entire HadCRUT4 trend ensemble ….” [WGI contribution, chapter 9, text box 9.2, page 769, and in full Synthesis Report on page SYR-8]
3. “There may also be a contribution from forcing inadequacies and, in some models, an overestimate of the response to increasing greenhouse gas and other anthropogenic forcing (dominated by the effects of aerosols).” [SPM, section D.1, page 13, and full Synthesis Report on page SYR-8]
4. “This difference between simulated [i.e. model output] and observed trends could be caused by some combination of (a) internal climate variability, (b) missing or incorrect radiative forcing and (c) model response error“. [WGI contribution, chapter 9, text box 9.2, page 769]
So there are the dry, technical phrases of the AR5, but fortunately John gives it in ordinary language for us. Excerpts and summaries follow (my emphasis).
Let me summarise them in simpler terms; there’s no certainty that there was any warming over the 15 years prior to the writing of the report, but almost all climate models falsely predicted that warming would occur, with some “over estimating” the influence of greenhouse gases, and it’s not clear why so many models failed.
The IPCC report also says that the human influence on climate is estimated by running the models first with greenhouse gases and then without, and then attributing the difference in output to those man-made gases.
Given that the models falsely predicted warming when there was none and exaggerate greenhouse gases, any estimates of human influences on climate are extremely likely to be wrong. The IPCC can’t honestly say if there’s a big influence or a negligible influence.
John said that the claim that our three public climate scientists, WRR, made in the Dominion Post, saying “Warming of the climate system is unequivocal, and human influence on the climate system is clear” is misleading and doesn’t give the whole picture.
[Astonishingly, the three scientists have put these two statements side by side with the intention of misleading us. They fully expect most of us (and they’re right to expect it) will tell ourselves “human warming of the climate is clear” though the statements don’t say it, and human warming is insignificant — in fact, it’s so small it hasn’t been detected yet. — RT]
He advises us to seek evidence to support claims like these, distinguish clearly between fact and opinion, and avoid sweeping generalisations or vague correlations — regardless of which side of the climate debate makes them.
WRR said: “A substantial contribution to the observed increase in average global surface temperature since the mid-20th century has come from increasing greenhouse gas concentrations.” But then John McLean was astounded—as any scientist would be—to read:
There is no other plausible way to explain the observed changes.
He says that is not a proper scientific approach; and I say it’s not true. [UPDATE 28 Mar 1300 NZDT: WRR appear to assume that scientists fully understand every detail of the climate, which is patently untrue. Or perhaps they simply omitted a few trailing words — “as far as we know” or “to the best of our knowledge” — maybe even “as far as we’re prepared to look.” Choose for yourself, gentle reader.]
He himself published a paper in October that draws on various data to provide a very plausible explanation that leaves little if any warming to be blamed on greenhouse gases or anything else. [UPDATE 28 Mar 1300 NZDT: Using temperature, ENSO and cloud cover data, McLean shows that the average global temperature anomaly was possibly driven by the ENSO from 1950 to 1986, then to 1997 by a reduction in total cloud cover and then, to 2009, when the cloud data end, a decrease in low level cloud but increase in mid and upper level cloud. This explanation is a good fit for a temperature anomaly pattern that was flat from 1950 to 1976, rose slightly from 1977 to 1986, rose about 0.4°C from 1987 to 1997 and since then has been flat.]
It’s not a very technical paper and is freely available. He says it has been downloaded 2863 times and he hasn’t seen any comments that seriously dispute its findings. I’ve just checked and the number of downloads has gone up to 2895 (one of them is mine).
Have a look. Tell us what you think.
- 08 to 0.14 ↩