The Taxonomy of Climate Opinion

Guest essay by Barry Brill

I’ve had it with tax-funded over-educated fools like Lewanadowsky presuming to categorize me on the basis of his own delusions. And I don’t appreciate Cook & co locating people in a 3% minority on the basis of infantile spin-driven surveys.

The debate over climate change is not, and never has been, divided into two monochromatic tribes who have been brainwashed into unanimity . There are as many different opinions are there are participants in the discussion. (“quot homines tot sententiae” as Christopher Monckton might say).

For those who insist upon a tidy taxonomy, I offer the following first draft:

[Note: this table was updated at request of the author on 10/9/13 to correct decimal point placements in the first three rows]

Whilst there are quite large numbers of people who are unconvinced that human activities can have any material effect on global average temperatures, the “Principia Scientific International” consortium, aka “Slayers of the Sky Dragon” strongly reject the enhanced greenhouse effect theory (AGW) which underpins mainstream climate science.

I’ve appropriated the term “Skeptics” to cover the broad tent of opinion which accepts that there has been some global warming since the LIA, to which human activities would have made some (probably trivial) contribution, through increased GHG emissions.

There is a collective view that average temperatures would increase by about 1°C if atmospheric CO2 concentration were to double from 280ppm (pre-1950), but a wide disparity of views regarding the sign and amplitude of net feedbacks. Most believe warming will be beneficial in the foreseeable future and none believes it poses a significant threat.

Lukewarmers are a subset of skeptics, who believe net feedbacks from warming to be slightly positive.

The ‘Breakthrough’ label is borrowed from the “Breakthrough Institute” but covers all who favour (limited) Government action other than emission-mitigation. This grouping broadly accepts IPCC temperature projections but believes the impacts have been exaggerated. They consider that an element of future threat arises and would combat this by promoting Government-sponsored breakthroughs in energy technology.

The IPCC, which presents “official” or “governmental” views, covers the broad tent which believes AGW is dangerous and should be combated by expensive emission-reduction programs. Its main controversial drivers are a belief in large net feedbacks (high ECS) and the use of unlikely scenarios to supply worst-case impacts.

Alarmists believe that irreversible and abrupt climate change is much more likely than indicated by Table 12.4 of AR5WG1, re-interpret the SREX report, and blame AGW for numerous other current or potential ills. They see climate change as a great moral challenge and believe decarbonization of the global economy is inevitable. This group (along with activists) controls a host of spin levers and secures a hugely disproportionate share of mainstream media attention.

Activists are usually members of groups which make a living from public donations and whose success depends upon maximising public fears. A sizeable proportion are malthusians or doomsayers who are philosophically opposed to economic growth/capitalism. Other members are lobbyists for commercial interests such as suppliers of renewables, carbon traders, consultants, gas producers, re-insurers, foresters and (until recently) bankers. They ignore all scenarios except the most extreme and are now adherents of the new RCP8.5.

The futility of consensus-seekers such as Cook and Oreskes is clear from the fact that the majority of almost all groups accept some 20th century warming (although now aware of “the pause”) as well as AGW theory. The dividing lines lie elsewhere.

The most visible division between climate opinion groups is the value they ascribe to equilibrium climate sensitivity (ECS). This, along with the associated transient climate response (TCR), is the key determinant of future temperatures and the extent of future threats, if any.

For 20 years or more, there has been a clear gap between the ‘most likely’ positions held by mainstream (3°C) and skeptic (1°C) groups. But the WG1 report of AR5 largely bridges that gap, and there is widespread expectation that the gap will close further when post-cut-off papers are brought into account.

AR5 recognises that those who calculate ECS at 1.5°C and/or TCR at 1°C are now mainstream scientists. An IPCC scientist modeling RPC2.6 and applying the lower end of the IPCC’s TCR will project warming of 1°C to be reached by about 2083 – of which about 0.8°C has already occurred. That result would not differ from the expectations of Skeptics. With warming much lower than last century, this science, now mainstream, clearly doesn’t justify anxiety or precipitate action.

We are now all part of the orthodoxy, separated only by a tendency to prefer higher or lower segments within the IPCC’s accommodating ranges.

At the Stockholm 4-day meeting of politicians/bureacrats, the AR5 scientists were directed that no ‘likely’ value for ECS/TCR was to be disclosed to the public. But everybody already knows the answer and the Stockholm ‘finger in the dyke’ manoevre will buy very little extra time.

The cut-off date for the 2013 WG1 was in February. A few weeks later^[1], The Economist reported two peer-reviewed Norwegian papers, one finding a most likely ECS of 1.9°C and the other a 90% likelihood of a 1.2-3.5°C range. It declared there was “much less controversy about the TCR. Most estimates put it at 1.5°C with a range of 1–2°C”.

In August, the Otto et al paper (whose author list includes several IPCC notables) found that TCR was 1.3°C and ECS was most likely 2°C but the 90% range should should extend down to 1°C. Pat Michaels has listed^[2] a raft of other authoritative papers which agree.

It is only a matter of time (and not much time) before the ECS is repositioned to 1-3°C and the TCR to1-2°C. At that point, many more people who are near the upper end of the ‘Sceptics’ grouping with join with those multitudes who are at the lower end of the ‘Mainstream’ grouping to form a new “Orthodox” group.

This merging could be an uncomfortable time for both parties. Kuhn argues in “The Structure of Scientific Revolutions” that rival paradigms are incommensurable—that is, it is not possible to understand one paradigm through the conceptual framework and terminology of another rival paradigm. Will that remain the case when views of TCR are only a fraction of a degree apart?

If further science grants are extended to Lewandowsky and his voyeuristic ilk, they should analyse the new minority groups – the alarmists and activists – not those who are now barely distinguishable from the mainstream.

^[1] http://www.economist.com/news/science-and-technology/21574461-climate-may-be-heating-up-less-response-greenhouse-gas-emissions

^[2] http://www.cato.org/blog/still-another-low-climate-sensitivity-estimate-0