That said, it should come as no surprise that too much of a good thing can be bad. To be a skeptic in the face of overwhelming evidence (with absolutely no contradictory evidence) is simply being obstinate. It is even worse when such stubborn skepticism is rooted in nothing more than ideology.
Today, when someone claims that the Earth is flat, we pat them on the head and think to ourselves "poor, deluded fool." We pity the person, because we know that they are wrong. We know this not out of arrogance, but because of the mountains of evidence (with zero evidence to the contrary). Even the ancients knew that the world wasn't flat. (Eratosthenes managed to come up with a fairly decent measurement of the Earth's circumpherence back in 240 BCE, and sailors had long noted that the tops of the sails of oncoming ships appeared on the horizon first.) We have circumnavigated the globe. We have seen our oblate-spheroid world from space, and even from the Moon. (Of course, the latter point is questioned by still another flavor of reality-deniers who are equally as wrong as the flat-Earthers. They persist in using the same arguments again and again, despite the fact that these arguments have been repeatedly and thoroughly debunked, a common characteristic among reality-deniers.) Moving from the realm of science to that of politics and history, we have Holocaust deniers, ranging from neo-Nazis to the current Iranian leadership, all ideologically driven to ignore the overwhelming evidence which proves them to be factually incorrect. One might as well deny the existence of gravity. Of course, all the denials in the world would not stop such a person from falling if they were to step off of a ledge. Reality ultimately trumps rhetoric.
There exist, however, other truth claims that are not so clear cut, at least without access to specialized or up-to-date knowledge. In the ancient world, it was obvious to sailors and scholars such as Eratosthenes that the Earth was round; but, as far as the bulk of humanity was concerned at the time, the Earth was indeed flat. The weight of the body of evidence had not yet built up to a sufficient preponderance to convince the skeptical, nor had the existing evidence yet found its way into the common body of knowledge and discourse. To compound this issue, the false claim of the Earth's flatness continued to be reinforced by obsolete false evidence, such as ancient theological cosmologies, which continued to be promulgated with a considerable societal inertia. This latter issue of a societal echo chamber is particularly pernicious in allowing false claims to linger well past all reasonable consideration.
All of this brings us to a modern truth claim which is of considerable significance to our species. I refer to anthropogenic climate change, or, as it is referred to in the common vernacular, global warming. The scientific evidence overwhelmingly supports it. Every single argument commonly leveled against it has been thoroughly and repeatedly debunked (see links below). And, most damningly, those who reject the reality of global warming are almost all far right wing conservatives. This idealogical connection is a major red flag. Would it not be the case, if there were valid objections to claims of global warming, that such objections would come from members of the entire political spectrum? It seems almost as if global warming denial is a prerequisite for labeling oneself as a conservative, and the right-wing radio and television pundits, bloggers, and politicians continue to peddle discredited false objections to the masses.
The circles of friends in which I move tend to consist of intelligent, rational people. A tiny subset of these friends, still, mind you, otherwise rational and intelligent, are quite conservative, and almost universally reject global warming claims. I've heard their arguments. I could argue back until I'm blue in the face, but it doesn't do any good. On this topic, purely on the basis of dogmatic ideology, they've rejected the real world. And that saddens me, because these are people I love and value as friends.
Here is some material that they really should read:
- RealClimate.org, a climate change blog maintained by actual climate researchers
- The RealClimate.org Wiki, the first group of links of which point to the following debunking sites
- How to Talk to a Climate Sceptic
- Climate change: A guide for the perplexed
- Responses to common contrarian arguments
- NERC Climate change challenge
- Climate change - the big picture
- Anti-global heating claims - a reasonably thorough debunking
- Myths vs. Facts: Global Warming
- Skeptical Science