First off, I am not a formally trained scientist. The literature of climate science gets very technical very quickly. This is not to say that scientists are always right. Even a cursory sifting of the available information reveals that opinions and theories differ widely between individual scientists, governmental agencies and international panels, as well as over time. To my eye (and to many other ordinary observers), climate science looks more like a work in progress than a masterpiece of scientific knowledge.
Second, the issue is about as politically charged as one can get. Conservatives cannot help but be skeptical when they hear avowed socialists proposing solutions to avoid a global warming doomsday that just happen to align perfectly with their dreams of ever-increasing social control. I suppose it is technically possible that the science does really indicate that our only hope for survival is to place our economic and individual freedoms in subservience to an international board of
I did manage to find this interesting site called Skeptical Science. It seems to be very damaging to my position, providing explanations for all the top arguments. I also found some interesting discussion in the comments section at the bottom of the article on that page. The number one argument against man-made global warming seems to be solar radiation. The standard answer seems to be that solar activity went flat around 1970 while global temperature continued to rise. This leaves CO2 as the only viable culprit. However, the estimates of solar activity might not be correct. The IPCC rates the Level of Scientific Understanding (LOSU) of solar irradiance as Low. NASA continues to learn more about the sun. Also, a recent study by Scafetta and Wilson (2009) suggests that solar radiation may account for nearly 65% of warming observed in the last 30-40 years.
Another promising argument seems to center around long-term hydrological cycles (see comment #6 on the Skeptical Science link above for more). These might also explain the past variations observed in Arctic ice. These would seem to be better predictors of droughts, etc., than global warming.
I will leave off with this. Sarah asked why I might object to global warming on theological grounds (as we are both Christians). In Genesis 8:22 (While the earth remaineth, seedtime and harvest, and cold and heat, and summer and winter, and day and night shall not cease.), God promises that the earth will remain habitable until the end. God's promise to never again flood the earth follows soon after. I believe in a God that controls and maintains our planet. As a result, I'm not very worried about us damaging the planet in any significant way. I certainly don't think we should go around wasting and destroying for no reason, but it is clear from Scripture that the earth is here for us and not the other way around.