Global Warming and Intuition

I recently was asked whether the proposition that a "dramatic increase" in CO2 since industrialization could cause worrisome global warming was "intuitive" or not. My interlocutor wanted simply a yes or no answer. But I replied that I couldn't answer either yes or no because, in my view, the question had contestable if not incorrect premises. For the same reason, the question "Have you stopped beating your wife?" is widely regarded as unfair. It's called a loaded question.

I pointed out that whether the CO2 increase is properly called "dramatic" is at least contestable. The descriptor is subjective. The increase from both natural and human causes since 1850--roughly 300 to 400+ parts per million) amounts to about one-third; at times long ago CO2 was many times higher than it is today, and fauna and flora flourished--we are their descendants. Princeton physicist William Happer says that according to geological standards we are in a "CO2 drought."

I also noted that the question implicitly assumes a highly oversimplified notion of "the climate," as if it were one unified thing and only two or three things mattered: CO2, which is only 0.04 percent of the atmosphere; water vapor; and global average temperature, a statistical construct compiled in part by using a noisy surface-temperature record. (The computer models that the UN Intergovernmental Panel on Climate Change [IPCC] relies on have badly overpredicted warming at every turn. They can't even predict the past!)

Since the day I was asked that question, I've thought a lot about how else I might have answered it. The word intuition is interesting. Consider the relationship between CO2 and the climate. A person who knew nothing about those two things, when asked what his intuition was about the effect of a dramatic increase in CO2, might well reply, "Since I know nothing about CO2 or climate, I have no intuition at all. How could I?" If you can't see the reasonableness of that answer, imagine you were asked to intuit what would happen to a beaker of water with the addition of hafnium (Hf), which by stipulation you've never heard of. (I hadn't until I wrote this post.) Would the water freeze, boil, overflow with foam, or do nothing? How could you possibly have an intuition about that? And what would it be worth if you did? You could guess, but that's not the same thing. 

(For the record, over geological time the correlation between CO2 and temperature is virtually nonexistent. See this graph. Looking at the last few hundred thousand years, a correlation can be found, but the causation runs the "wrong" way, that is, the rise in temperature preceded the rise in CO2 by several hundred years and even as much as a thousand years. NASA states, "While it might seem simple to determine cause and effect between carbon dioxide and climate from which change occurs first, or from some other means, the determination of cause and effect remains exceedingly difficult. Furthermore, other changes are involved in the glacial climate, including altered vegetation, land surface characteristics, and ice sheet extent." Why don't alarmists tell the public this?)

Thus the value of a person's intuition about anything depends on how much he knows. Or so it seems to me.

Here's another thing. If someone intuits that a rise in CO2 would cause the earth to warm, that is not terribly informative because it leaves open the question of magnitude and consequences. How much will the earth warm, and--importantly--would that magnitude of warming help, hurt, or be neutral for human beings? In other words, someone could answer yes to the question without being very informative at all.

Intuition without good information isn't worth a wooden nickel. At best it's a starting point for an honest inquiry.