This article by Frederick Colbourne appeared as a comment at the article
“Some thoughts on ‘Climate Change is Real, and Important’”. We thought it deserved reposting as an article. I’ve provided the title, and made a couple of minor corrections.
Fred posts at https://geoscienceenvironment.wordpress.com/
Geoff Chambers

I am not a practicing scientist, though I have some background in half a dozen fields of science, including master’s degrees in both Geography and Earth Science. My interest in climate science extends back 50 years.

Philosophical Beliefs
In my opinion, philosophical beliefs play an important role in science. My philosophical position is “entity realist”. I take entities, such as “photons”, to be real. I take theories about photons not to be real. Theories are attempts to explain the behaviour of photons. Theories sometimes become dogmas defined as teachings akin to religious beliefs. Professors sometimes pose as prophets of a belief system. Thomas Kuhn wrote extensively about this phenomenon.
[Reference to entity realism: Ian Hacking and Nancy Cartwright:] http://www.soc.iastate.edu/sapp/phil_sci_lecture19.html
From the point of view of entity realism, I find issue with the definitions of the terms “climate”, “global climate”, “climate change”, and “global climate change”. I am skeptical about whether these putative entities are real.
I am not skeptical about most entities used by atmospheric physicists and geophysicists to describe the Earth’s energy transfers via the atmosphere, the solid earth or the oceans.

Climatic Regions
I readily accept geographers’ descriptions of climatic regions as being useful. (Examples: Koppen, Thornthwaite, Trewartha). The WMO appears to claim that such theoretical constructs represent real entities (http://glossary.ametsoc.org/wiki/Climatic_classification). In my opinion some French geographers were closer to the mark in describing climate as part of the “personality” of a region in the same way that they might describe a vintage wine.
Having lived and worked on all continents except Antarctica, I find these classification systems as useful for travel, economic analysis, teaching geography and making documentary series or chapter outlines for books, but not for scientific purpose.
In my opinion, neither “climate” nor “global climate” are real entities.

Climate Change
However, if I assume climate and global climate to be real entities, I ask, “What does it mean to say that these real entities are subject to change?”
Does it mean that a marine climate can become a continental climate? Or that a Mediterranean-type climate can become a steppe-type climate or a desert?
On the scale of millennia, such changes have taken place, such as over 20,000 years ago, during the last maximum extent of continental glaciers. As recently as 5000 to 6000 years ago, extensive areas of what is now the Sahara Desert was steppe, inhabited by cattle herders.
On the scale of centuries, does climate change? We know that temperature and precipitation fluctuate, sometimes departing substantially from mean values. We know also that temperature and precipitation revert to mean values on centennial time scales.
The evidence is that present European climatic regions are similar to those existing during Roman times. We know that temperature and precipitation fluctuate over many different time scales. But geographers do not change climatic classifications during periods as short as a century.

Global Climate Change
I ask “Does Earth have a climate?” It seems obvious to me, and to generations of geographers, that Earth does not have a climate, but rather several climates arranged in loosely systematic ways across its continents, duplicated to some extent in both hemispheres.
By contrast, physicists do not approach climate by classifying regions. Instead physicists focus on energy transfers and energy storage. The primary media for energy transfers and storage are liquid water, atmospheric gases (including water vapour) and the solid earth, including ice (a form of rock). The oceans are the main storage depots for accumulated energy.
Some scientists have asserted that climate is cyclical, supporting their claims by reference to the alternation between warm periods (Minoan, Roman, Medieval) with intervening cold periods. Hubert Lamb, founder of the CRU at the University of East Anglia, was one of these scientists.
In the definition of “cyclical”, I include quasi- and pseudo-cyclical changes, where these terms mean “sort of cyclical but not regular or predictable”.).
The alternative to identifying cycles is to identify trends as monotonic change (one-directional change) up or down. Economists refer to a monotonic change as a “secular change”, from the Latin “per secula-seculorum”, “for evermore”, signifying that reversing direction is not expected.
Inflation is described by economists as secular. Anthropogenic global warming is described as a secular climate change. Theory states that unless mankind stops doing the things that cause global warming, the direction of temperature change will be secular, trending upward.

The Scientific Problem
The problem for me is this. When does a “cycle” become long enough and strong enough to be considered a trend? Stock market statisticians ask this question all the time. Statisticians tell us that the stock market is a random-walk with no cycles and no trends.
By definition cycles and trends are not random, but driven by external forces.
For me the number one question is the relative power of natural and man-made forcing. There are various ways of posing the question:
– How do we know that temperature and precipitation are not random walks?
– Have we truly shown that natural forces are weak compared with human forces?
– How do we know that the putative secular trend toward warming is not merely the upward phase of a cycle that will eventually reverse direction?
Even if we accept that changes in temperature and precipitation are non-random, we still have to ask whether or not a change is part of a long natural cycle or part of a natural trend, and whether or not the trend is short, long or secular with no expectation of reversal in trend.

Empirical Position versus Theory
This is about as strict an empiricist position as is possible to adopt, but consistent with the philosophical stance of an entity realist. I am skeptical about the theory, and this skepticism extends to the definition of entities defined by the theory, at least as those entities are presented to the public.
(I note that most scientific papers, such as those supported by NASA, are not based on the entities that I deprecate. Which is one reason it may be said that discussions among scientists is different from statements by scientists to the public.)

Theorists and Empiricists
All of which leads me to your comment [1] about extremist positions by parties to the debate about climate change.
[1] see article: https://cliscep.com/2015/11/01/some-thoughts-on-climate-change-is-real-and-important/
In my opinion, those who claim that humans are responsible for changing climate in an irreversible manner base their claims on theory, while skeptics tend to be more empirical, so much so that many are entity realists.

Déjà vu (All over Again)
The science community has been down this dead-end road less than 100 years ago in the debate about whether or not continents are mobile. They are. Continental convergence and divergence have been measure by GPS technology. The rate of movement averages about the rate of growth of fingernails.
Geographers, geologists and palaeologists have had the evidence for continental mobility much longer than 100 years, the most obvious being the fit between the east coast of South America and the west coast of Africa. But the physicists did not have a theory, and so they rejected the empirical evidence until the 1960’s when plate tectonics became established. Before 1960 or so, it was not possible to keep a job teaching at a public university in the US if you were known publicly to hold that continents were mobile.
In my opinion, the big gulf between the “consensus” and the skeptics is the same gulf between theorists and empiricists as it applied to continental mobility. In the US the gap seems to be greater than in the UK and Western Europe, at least among the public.