Bob Carter published a paper titled “The Myth of Dangerous Human-Caused Climate Change”, in which he purports to dismantle the so called ‘alarmist’ science of global warming. Part I is a fairly light introduction. Part II digs into Carter’s claim that we have no theory of climate and hence can’t deal with what climate information we do have. In Part III, I addressed Carter’s statements about carbon dioxide. Carter then takes up the issue of general circulation modeling– that is, computer modeling– of global climate. That is the subject of Part IV.
Now, “Is there a consensus?”
Let’s be clear: the work of science has nothing whatever to do with consensus. Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right, which means that he or she has results that are verifiable by reference to the real world. In science consensus is irrelevant. What is relevant is reproducible results. The greatest scientists in history are great precisely because they broke with the consensus.
Michael Crichton, as quoted by Carter.
If four cancer specialists told you that you needed chemotherapy desperately and immediately, and one said “Go home. Don’t worry about it. You’re alright.” what would you do?
If four engineers told you that a bridge was in imminent danger of collapse, but one said “Ah… no problem” what would you do?
If four airline mechanics insist that “this plane can’t fly” but one gives it the “OK” what is the reasonable course of action?
In the real world, consensus does matter. It would be insane to ignore the four cancer specialists in favor of the one, and it would irresponsible to let rush hour proceed as planned across a bridge that four engineers fear will collapse. It is true, consensus can’t trump data. In the real world, though, the data is not often a hard black or a hard white. The data requires interpretation. Crichton makes the mistake of assuming, or insisting, or pretending that the world is easily divided into “absolutely right answer” and “absolutely wrong answer”. Rarely is that so. He makes the mistake of thinking that experiments spit out clean answers, that data does not need to be interpreted.
Carter follows Crichton’s lead, and by so doing implicates himself in the same conceptual errors. “It would be hard,” he writes, “to write a more accurate statement about the way that science works than Crichton’s pithy summary.” Crichton’s summary is of science in its idealized state. It is a ‘perfect world’ science. It is an abstraction. Like any stereotype, it is based in reality. And like any stereotype, it rarely ever matches actual messy reality.
It is peculiar, though a minor point, that Crichton himself, in making his case against ‘consensus’, appeals to consensus. “…which means that he or she has results that are verifiable by reference to the real world.” Think about what that means. True, Crichton writes “verifiable by reference to the real world” but how, in practice, is some result demonstrated to be “verifiable by reference to the real world”? Answer: other scientists look at the data, look at the experiment, and conclude that the results are or are not in fact verifiable. In reality, appealing to “one investigator who happens to be right” is rather immature. Real systems and real problems are far too complicated to expect, or to trust, such assertions. I can appeal to “one investigator” from now to my grave but unless that one investigator is verified by other people, perhaps by myself, it hardly matters.
Carter uses Crichton’s conception of science and his critique of consensus ultimately to try to discredit the IPCC as a political body. This despite the large numbers of scientists who collaborate on the IPCC’s reports. “[S]tatement that ‘there is a consensus that global warming will occur’ convey sociological rather that scientific information,” he writes. I wonder if Carter believes that statements such as “the consensus is that Einstein’s theory of general relativity is the best solution to a number of fundamental problems in physics” conveys sociological information rather than scientific? The statement happens to be true, but there are dissenters from relativity. Should I appeal to one of those dissenters and dismiss the rest? I could, of course, spend the next twenty years studying physics and then sort through the evidence myself, which brings me to a critical point.
Relativity can wait, and the decision is not on the shoulders of the general public. Global warming, if it is in fact occurring due to human activity, can’t wait and that decision is on the shoulders of the general public. We are in the position of the cancer patient mentioned above. We can’t really wait to become specialists. We have to decide soon and on the advise of the specialists. We have no other practical choice.
Carter closes by claiming that it is “now agreed by both main sides to the global warming dispute [that] the consensus advice tendered to the governments by the IPCC is political and not scientific”. I don’t know how this can be true given the number of scientific bodies that have concurred with the findings of the report.