One scientist I heard made this remark concerning AGW- "When the science is on your side, you debate the science. When it's not, you attack the messenger".
Al Gore is certainly the messenger, and his name alone seems to be considered as an argument by the non-science trained denialists (who again, are almost all right wing ideologues with no science understanding who are trying desperately to protect corporate interests at the expense of truth. They are basically people rooting for their favorite football team).
So here is the long list of arguments made by the global warming denialists. I didn't make this up. This is a compilation of several other brainstormers and people with degrees studying climate science who have more knowledge and experience in debating denialists. I added one that I thought was missing from their list and I'll start with it-
From "The Top 10 Ways to Tell That a AGW Denialist Hasn't Done Any Honest Research" (warning, far more than 10)
*Attacks the sensationalist media as if the hype itself is evidence that AGW doesn't exist at all.
*Criticizes (or just mentions) Al Gore like that's a piece of evidence
*Claims that as many or more scientists doubt AGW as agree with it.
*Asks a simple question like "If humans are causing global warming, what made the planet come out of the last ice age?"
*Claims the current warming is part of a 'natural cycle' and doesn't know what causes natural cycles.
*Claims the current warming is due to the Sun even though no scientific study has come to this conclusion.
* Claims "Global warming has stalled" due to too small of a sample size in temperature data which flattens the graph and misrepresents overall trendlines.
* Makes a political remark (i.e. communist, liberal, etc.) as a refutation
* Makes a conspiracy remark (i.e. it's just the UN trying to take over the world). Or my personal favorite, "follow the money"
*Thinks scientists haven't considered the fact that climate has changed in the past, or that Mars is warming.
* Thinks the greenhouse effect is unproven
* Thinks that one volcanic eruption emits more CO2 than humans have in 5,000 years.
* "It's snowing in Vermont in the middle of winter. Where's global warming?!"
* Can't answer a simple scientific question (i.e. how is the observed increase in greenhouse gases NOT causing warming?)
* Cites JunkScience, Fox News, right-wing blog, Inhofe's site, etc..
* Makes absurd claims with zero citations
* Blames global warming on water vapor, cow farts, beer/soda carbonation, etc.
* "Models are just guesses" or "we can't predict the future"
* "Soon they're going to tax us for breathing!"
* Cites one outlying study and claims it disproves dozens of others which are in agreement
* Cites one scientist who has ignored the data and contradicted thousands of others
* "Warmer is better"
* "More CO2 is good for plants"
* "They predicted global cooling/an ice age in the 1970s"
* "They can't even predict the weather right for next week"
* "The Earth is 4.5 billion years old and we only have good data for 50/100 years"
* "Scientific consensus has been wrong before" or "the scientific consensus used to be that the Earth was flat!"
* Does not know what a peer reviewed journal is.
* Presents old theories already proven wrong as "new evidence"
* Uses a small part of an article taken out of context while the main article (complete) would contradict them
* States a political think tank as a "reliable source"
* Confuses vast timespans in the past with small windows of time in the present
* Argues that any advancement toward clean technologies will put us back to the stone age
* Quickly turns the issue to China and India and away from the science.
* Has a Christian fundamentalist worldview
* They complain about the word "consensus," as if the word did not imply that alternate theories were considered or as if the IPCC process did not include and consider skeptic opinions such as Gray, Lindzen, McKitrick, et al. They were considered, the consensus was reached. Get over it.
* Global warming science is labeled "fear-mongering," which ironically overlooks that claiming that there is a global conspiracy is the only clear fear-mongering present
* They use any variation of the glib "why is warming so bad?" line, which fails to consider the results of past warming on earth (extinction of most species on the planet; look up the Permian Triassic Extinction)