It is troubling that the proper methods of scientific argument are not being brought to bear on the issue of global warming. This issue is meant to be based on good science practice, scientific evidence and the evaluation of that evidence. Briefly to run over the background science, the presence of carbon dioxide in the atmosphere creates a greenhouse effect which contributes to keeping the atmosphere warm. This is accepted by all scientists. The global warming scenario then arises because we have injected a good deal of carbon dioxide into the atmosphere through our activities – such as burning coal. This extra carbon dioxide may cause the atmosphere to warm to unnaturally high temperatures with potentially devastating consequences. Scientists have spent many years trying to discover if this scenario is correct. Environmentalists say yes, skeptics say no. Among the scientists, the great majority say yes but a small and vociferous minority are crying no! What are we to make of this?
The way scientists work is as follows. We scientists, Background check near me and I am one of them, have some hypothesis, some idea which we want to test. We make observations and do experiments, often backed up by calculations. What we look for is some test that can in principle prove that we are wrong; that is, we look for tests that could in principle show that our hypothesis is incorrect. It is essential that such tests exist. If you can come up with no test which you can perform which may in principle show that your idea is wrong, scientists will rightly turn their backs on you. This may at first seem a bit odd, but it is the way we work. What you do is to show that neither you nor anyone else can show that you are wrong; ergo, you are probably right! Remember that an observation that fits with your hypothesis is not in itself proof that your hypothesis is correct, since who is to say that some other hypothesis might not also fit the observations just as well?
Let’s give an example where two competing ideas came into collision. A classic case of this is the Copernican system vs the age-old Ptolemaic system of the sun and planets. The Copernican system with the Sun at the centre was not accepted on both scientific as well as religious grounds at the time when it was promulgated, because the Ptolemaic system worked just as well – in fact better in some ways. There was no clear way to prove either system wrong, at the time.
Another and recent example is the ozone depletion problem of the 1980s and 1990s. The hypothesis is (was) that the release into the atmosphere of the chemicals used in fridges, and for hairspray and so on, could cause ozone to be depleted in the upper atmosphere. The test to show that this could be wrong is as follows. If we observe the ozone concentration in the upper atmosphere over a period of time and find that it is not reduced, then this falsifies the hypothesis that human actions are causing ozone depletion – since there is nothing to explain. Note that the opposite observation of finding depletion of ozone does not prove that human actions are causing ozone depletion. Something is doing it, but not necessarily human action.
A positive observation of depletion therefore leaves the question open of whether depletion is natural or due to human activity. All we can do for certain is to falsify the hypothesis that human activity is causing ozone depletion. What actually happened with ozone was the discovery of a massive ozone hole over the Antarctic, representing a dramatic depletion of ozone. Coupled with sound observational evidence of all sorts, for which a Nobel Prize was given, this ozone hole lead to swift and decisive international action in the form of the Montreal Protocol. Thus while we can initially only falsify a hypothesis, the great weight of evidence can be extremely convincing of the truth of a hypothesis. The risk that we were the cause of the ozone hole was very great indeed.
The same scientific method is not being applied in the case of the global warming debate. Indeed this method cannot, in my opinion, be applied. However the debate is presented as essentially a scientific debate, with the many political and economic ramifications which follow put forward as resting upon the results of an objective scientific debate. I would contend that it is not an objective scientific debate, simply because the rules of science are not being followed. I suggest instead that it is a debate about perceived risk. What is the risk of the climate skeptics being wrong? What is the risk of the environmentalists (if I may call them that) being wrong? Rather than go on in this dry manner, I should like to present the reasons for my view by recounting a fictional conversation between two physicists, Horace and Twinkle.
Before we start, I would like to remind you that there are two sorts of climate skeptics: the absolute skeptics who deny that there is any global warming at all and the relative climate skeptics who agree that there is evidence for global warming but that it is not caused by our introduction of additional carbon dioxide into the atmosphere, that is, it is not our fault. Rather, the observed warming is just some part of a natural warming cycle. Horace below lies somewhere in between, mostly relative but with a touch of the absolute.
Enter Horace and Twinkle; they sit down together with their coffee in the cafeteria on the seventh floor of a famous Physics Department, which will remain unnamed. The cafeteria overlooks the harbour and you can see way over to the hills on a clear day like the present one. But it’s not the view that interests them. It’s an old theme which they focus on. Horace is a climate skeptic. Twinkle, his friend, believes that humans cause global warming and that ‘something must be done about it’.