March 21, 2016, 9:02 am

Last month I outlined my position on global warming to a fabulous audience at the Athenaeum at Claremont-McKenna College. In doing so, I had a chance to substantially update my presentation materials. I realized that it had been years since I had posted this presentation as anything but a video, and so I embark over the next several weeks to lay my position out in a multi-part written series.

Table of Contents (updated as new chapters are added)

I suppose the first question I need to answer is: why should you bother reading this? We are told the the science is "settled" and that there is a 97% consensus among scientists on .... something. Aren't you the reader just giving excess credence to someone who is "anti-science" just by reading this?

Well, this notion that the "debate is over" is one of those statements that is both true and not true. There is something approaching scientific consensus for certain parts of anthropogenic global warming theory -- for example, the fact that CO2 is a greenhouse gas and that concentrations of it in the atmosphere have a warming effect on the Earth is pretty much undisputed in all but the furthest reaches of the scientific community.

But it turns out that other propositions that are important to the debate on man-made global warming are far less understood scientifically, and the near certainty on a few issues (like the existence of the greenhouse gas effect) is often used to mask real questions about these other propositions. So before we go any further , it is critical for us to get very clear what exact proposition we are discussing.

At this point I have to tell a story from over thirty years ago when I saw Ayn Rand speak at Northeastern University (it's hard to imagine any university today actually allowing Rand on campus, but that is another story). In the Q&A period at the end, a woman asked Rand, "Why don't you believe in housewives?" and Rand answered, in a very snarky fashion, "I did not know housewives were a matter of belief." What the woman likely meant to ask was "Why don't you believe that being a housewife is a valid occupation for a woman?" But Rand was a bear for precision in language and was not going to agree or disagree with a poorly worded proposition.

I am always reminded of this story when someone calls me a climate denier. I want to respond, in Rand's Russian accent, "I did not know that climate was a matter of belief?"

But rather than being snarky here, let's try to reword the "climate denier" label and see if we can get to a proposition with which I can agree or disagree.

Am I, perhaps, a "climate change denier?" Well, no. I don't know anyone who is. The world has had warm periods and ice ages. The climate changes.

OK, am I a "man-made climate change denier?" No again. I know very few people, except perhaps for a few skeptics of the talkshow host variety, that totally deny any impact of man's actions on climate. Every prominent skeptic I can think of acknowledges multiple vectors of impact by man on climate, from greenhouse gas emissions to land use.

If you have to slap a label on me, I am a "catastrophic man-made climate change denier." I deny the catastrophe. Really, I would prefer "catastrophic man-made global warming denier" because there is no mechanism by which man's CO2 emissions can affect climate except through the intermediate step of warming. The name change from "global warming" to "climate change" was, to my mind, less about science and more about a marketing effort to deal with the fact the temperatures had plateaued over the last 10-20 years and to allow activists to point to tail of the distribution weather events and call them man-made. But we get ahead of ourselves. We will discuss all of this in later sections.

In this series I will therefore be discussing what I will call the "Catastrophic Man-Made Global Warming Theory." There are a lot of moving parts to this theory, so I will use the following framework as a structure for my discussion.

This framework follows the work of the UN IPCC, an international panel that meets every 5 years or so to summarize the state of climate science in general and catastrophic man-made global warming in particular. While I will obviously disagree with the IPCC canon from time to time, I will try to always point out when I do so. However, I don't think any climate scientists would argue with the framework I am using here to describe their theory.

The first thing you will see, and perhaps the most important single point you should take away from this discussion, is that the core theory of catastrophic man-made global warming is actually a two part theory. In part one, which is essentially greenhouse gas theory, a doubling of CO2 warms the Earth by a bit over 1 degree Celsius. But there is a second part of the theory, a theory that is entirely unrelated to greenhouse gas theory. That theory states that the Earth's climate systems are dominated by positive feedbacks which multiply the initial warming from CO2 by 3- 5 times or more.

It is this two-part theory that causes me, and many other skeptics, the most frustration in the climate debate. For when advocates say the science is "settled," they really mean that greenhouse gas theory is pretty well accepted. But this is only one part of a two-part theory, and in fact the catastrophe actually comes from the second theory, the theory that the climate is dominated by positive feedbacks, and this second theory is far from settled. But again, I get ahead of myself, we will cover this all in great depth in later sections.

No theory in science has any meaning until it is confirmed by observations, so the bottom half of our framework deals with observational evidence for the theory. The IPCC claims that the Earth has warmed about 0.8C over the last century, and that [much/substantial/most/all/more than 100%] of this warming is due to man. The IPCC and many scientists have played with the wording of the amount of warming attributable to man over the years, and rather than deal with that complexity here, we will wait until we get to that section. But it is fair to say that IPCC canon is that man's contribution to the warming is probably not less than half and could be more than 100%.

Finally, on the right of our framework, this man-made warming has the potential to cause all sorts of changes -- to weather patterns, to animal species, to disease vectors -- you name it. Pick any possible negative effect -- more hurricanes, more tornadoes, more heat waves, more snow, less snow, lower crop yields, more malaria, more rain, less rain, more terrorism, rising sea levels, displaced persons, more acne, etc. etc. -- and someone has been quoted in the media claiming the link to warming. When something bad happened in Medieval Europe, it was typically blamed on Jews or marginalized women (via witchcraft accusations). Today, global warming is the new all-purpose target of blame.

Over many installments and several weeks, I hope to walk through this framework and discuss the state of the science (for those who can't wait, I wrote a much shorter overview here several years ago). We will discuss parts of the science that are well-grounded -- such as man-made warming from greenhouse gas theory and the fact that the Earth has warmed over the last century. We will discuss parts of the science I consider exaggerated -- such as the claim of large positive feedback multipliers of future warming and attribution of all past warming to man. And we will discuss parts of the theory which, despite constant repetition in the press, have absolutely no evidence behind them whatsoever -- such as the claim that we are already seeing negative effects from warming such as more hurricanes and tornadoes.

Part 2 on the greenhouse gas theory continues here.