My posting of the graphic to the left indicates that I am a skeptic about global warming (GW). To be precise, I am skeptical about some, not all, of the claims made by the GW activists. See below for some necessary distinctions. Skepticism is good. Doubt is the engine of inquiry and a key partner in the pursuit of truth.
A skeptic is a doubter, not a denier. To doubt or inquire or question whether such-and-such is the case is not to deny that it is the case. It is a cheap rhetorical trick of GW alarmists when they speak of GW denial and posture as if it is in the ball park of Holocaust denial. People who misuse language in this way signal that they are not interested in a serious discussion. When GW activists speak in this way they give us even more reason to be skeptical.
What can a philosopher say about global warming? The first thing he can and ought to say is that, although not all questions are empirical, at the heart of the global warming debate are a set of empirical questions. These are not questions for philosophers qua philosophers, let alone for political ideologues. For the resolution of these questions we must turn to reputable climatologists whose roster does not sport such names as 'Al Gore,' 'Barbra Streisand,' 'Barack Obama,' or 'Ann Coulter.' Unfortunately, the global warming question is one that is readily 'ideologized' and the ideological gas bags of both the Right and the Left have a lot to answer for in this regard.
I have not investigated the matter with any thoroughness, and I have no firm opinion. It is difficult to form an opinion because it is difficult to know whom to trust: reputable scientists have their ideological biases too, and if they work in universities, the leftish climate in these hotbeds of political correctness is some reason to be skeptical of anything they say. (Both puns intended.)
For example, let's say scientist X teaches at Cal Berkeley and is a registered Democrat. One would have some reason to question his credibility. He may well tilt toward socialism and away from capitalism and be tempted to beat down capitalism with the cudgel of global warming. Equally, a climatologist on the payroll of the American Enterprise Institute would be suspect. I am not suggesting that objectivity is impossible to attain; I am making the simple point that it is difficult to attain in a subject like this and that scientists have worldview biases like everyone else. And like everyone else, they are swayed by such less-than-noble motives as the desire to advance their careers and be accepted by their peers. And who funds global warming research? What are their biases? And who gets the grants? And what conclusions do you need to aim at to get funded? It can't be a bad idea to "follow the money" as the saying goes.
Off the top of my head I think we ought to distinguish among the following questions:
1. Is global warming (GW) occurring?
2. If yes to (1), is it naturally irreversible, or is it likely to reverse itself on its own?
3. If GW is occurring, and will not reverse itself on its own, to what extent is it anthropogenic, i.e., caused by human activity, and what are the human causes?
(3) is the crucial empirical question. It is obviously distinct from (1) and (2). If there is naturally irreversible global warming, this is not to say that it is caused by human activity. It may or may not be. One has to be aware of the post hoc ergo propter hoc fallacy. Suppose there is a close correlation between global warming and man-made carbon emissions. It doesn't straightaway follow that the the human activity causes the warming. But again, this is not a question that can be settled a priori; it is a question for climatologists.
4. If anthropogenic, is global warming caused by humans to a degree that warrants action, assuming that action can be taken to stop it?
5. If GW is caused by humans to an extent that it warrants action, what sorts of action would be needed to stop the warming process?
6. How much curtailment of economic growth would we be willing to accept to stop global warming? And what other effects on human beings could the anti-global warming policies be expected to have?
The first three of these six questions are empirical and are reserved for climatologists. They are very difficult questions to answer. And it is worth pointing out that climatology, while an empirical science, falls short of truly strict science. This useful article lists the following five characteristics of science in the strict and eminent sense:
1. Clearly defined terminology.
3. Highly controlled conditions. "A scientifically rigorous study maintains direct control over as many of the factors that influence the outcome as possible. The experiment is then performed with such precision that any other person in the world, using identical materials and methods, should achieve the exact same result."
4. Reproducibility. "A rigorous science is able to reproduce the same result over and over again. Multiple researchers on different continents, cities, or even planets should find the exact same results if they precisely duplicated the experimental conditions."
5. Predictability and Testability. "A rigorous science is able to make testable predictions."
These characteristics set the bar for strict science very high, and rightly so. Is climate science science according to these criteria? No, it falls short on #s 3 and 4. At the hardest hard core of the hard sciences lies the physics of meso-phenomena. Climatology does not come close to this level of 'hardness.' So don't be bamboozled: don't imagine that the prestige of physics transfers undiminished onto climatology. It is pretty speculative stuff and much of it is ideologically infected.
Our first three questions are empirical. But the last three are not, being questions of public policy. So although the core issues are empirical, philosophers have some role to play: they can help in the formulation and clarification of the various questions; they can help with the normative questions that arise in conjunction with (4)-(5), and they can examine the cogency of the arguments given on either side. Last but not least, they can drive home the importance of being clear about the distinction between empirical and conceptual questions.