4) Mars has also been experiencing global warming. Since man can't be a factor on that planet, doesn't it suggest that perhaps a factor other than man, i.e. the sun, is responsible for the warming on both planets?
5) Back in the early seventies, the in-vogue scientific theory was that we were in the midst of global cooling that was caused by man. Now, it turns out that there was nothing much behind that except that the global temperature was getting cooler. So, where did they go wrong back in the early seventies and how do we know that we're not making the same type of mistake today in forecasting global warming?
6) Global warming alarmists will tell you that there is "scientific consensus" that mankind is causing global warming and that only a few scientists disagree. But, there are more than 17,200 scientists who say that, "There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gasses is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate." Since that's the case, how can anyone credibly claim that there is "scientific consensus" on the issue?
7) Even if mankind was responsible for global warming, how would the solutions that are being offered, like Kyoto or carbon credit trading schemes, fix the problem? Big developing countries like India and China are exempt from Kyoto and unlikely to sign on to any deal that hurts their economy, Europe isn't meeting its Kyoto goals, and environmentalists say Kyoto wouldn't fix the problem even if all of its targets are met.
8) In Bill Bryson's book on science, "A Short History Of Nearly Everything," (and yes, Bryson does appear to be a believer in manmade global warming), he notes that,
"For most of its history until fairly recent times, the general pattern was for earth to be hot with no permanent ice anywhere." -- P.427
That would seem to suggest that despite everything we hear about the "hottest temperatures on record," the global temperature is significantly cooler than it has been throughout much of earth's history. Since that's the case, is the small change in global temperature we've seen so far really out of the ordinary or anything to be alarmed about? 9) As Carl Zimmer has noted in Discover, at times in the earth's past, we've had considerably more carbon dioxide in the air that we do today, and yet it's debatable whether the temperature was significantly warmer,
"During the Ordovician Period, 440 million years ago, there seems to have been 16 times as much carbon dioxide in the atmosphere as there is today--and yet, judging from the gravelly deposits it left behind, there was also an ice sheet near the South Pole that was four-fifths the size of present-day Antarctica. The second exception is even more troubling. The Cretaceous Period, when dinosaurs ruled the Earth and CO2 levels were about eight times what they are today, has been one of the most popular case studies for global warming forecasters. And everyone knows what the climate was like during the dinosaurs’ heyday: steamy. Or was it? The latest evidence, reported just this past summer by British researchers, suggests that temperatures in the tropics 95 million years ago were no higher than they are now; and while it was a lot warmer at the poles than it is today, it was still freezing cold."
Doesn't this suggest that there isn't anywhere near as much of a close relationship between greenhouse gasses like carbon dioxide and the temperature as many people seem to believe?
10) Skeptics of manmade global warming have often pointed out that the rise in global temperature seems to track much more closely to increased solar activity than it does to an increase in manmade greenhouse gasses. Doesn't that seem to strongly suggest that the sun, not mankind, is more likely to be responsible for global warming?
Bonus Question) If people like Al Gore believe their own hype and think it's necessary for us to cut back our energy consumption, why aren't they practicing what they preach? If a global warming fanatic like Al Gore can’t get by on less than 20 times the amount of energy that a regular family uses, how can we reasonably expect the average family to dramatically cut their energy usage?
Quite frankly, if you buy into manmade global warming, you should have good answers for these questions or, if you don't, admit that your opinion is based more on faith and guesswork than it is on science.