In the environmental community, people who dispute the current Global Warming theories are generally looked upon as heretics. Global Warming has become the darling cause of the left, because it makes it possible to wrap anti-industrial and anti-capitalist sentiment in the mantle of social respectability.
Is there such a thing as global warming?
Yes, without a question. The planet is getting warmer, no doubt about it. That part of Global Warming Evangelism is true.
What Al Gore and his save-the-spotted-owls brigade aren't telling you is that the planet routinely gets warmer and colder, in roughly 500-year cycles, and it has done so since pretty much the dawn of recorded history.
Around the birth of Christ, the planet went through a warm spell, making it possible for the Romans to extend into the north of what is now the British Isles. Between 300 and 800 AD, the planet went through a cold period, which caused some of the Germanic tribes to migrate south in search of new pastures. In the early Middle Ages, another warm spell followed (the "Medieval Warm Period", also called the Medieval climate optimum), where wine was growing in Newfoundland, and the German Rhineland supported the cultivation of figs and olives.
Now, the medieval period is marked by a distinct lack of industrialization, and combustion engines were similarly scarce. What evil human interference caused the Medieval Global Warming?
(Must have been all the witches they burned. It is a known fact that not only did Medieval Europe burn billions of witches every year, but also used them for fuel in hovel and castle alike. They also built bridges out of them.)
From 1300 to roughly 1700, we have another cold period that is documented well enough to go by the moniker of "Little Ice Age". Around 1800, the planet warmed up again. All of these climate changes happened with the CO2 content of the atmosphere remaining basically static.
Human production of CO2, natural (by aspiration) or artificial (by combustive processes) counts for only 1 to 4% of the world's CO2 generation. All the world's cars create 2.1 billion tons of CO2 annually; the world's humans create 2.5 billion tons of it just by breathing. The vast majority of the world's CO2 comes from animal exhalations and ocean water evaporation.
Even such respected newspapers as the Frankfurter Allgemeine (Germany's rough status equivalent to the New York Times) are concluding (grudgingly, in some respects) that cars and other human inventions have little to do with CO2 levels, and that even if Germany outlawed all combustion engines overnight, it would have no effect at all on the global climate. The Frankfurter Allgemeine article concludes that human contributions to CO2 production shouldn't be denied or belittled, but that they're not suitable for supporting a "climate hysteria".
Science is all about facts. Gather the data, observe and record, and come up with a conclusion that's supported by evidence, regardless of whether your emotions contradict that solution. The truth is the truth, and your emotions have no bearing on the data. It's funny how the left-leaning crowd makes fun of the Creationists for selectively reading evidence and ignoring the bits that don't fit their desired conclusion, and then turns around and commits the same fallacy in their own arguments. Once you do that, you're no longer practicing science, but theology, and the way in which the climate warriors deal with dissidents in the scientific community makes one think of the medieval church persecuting heretics.