Right. Whatever.
http://scienceblogs.com/illconsidered/2008/07/how_to_talk_to_a_sceptic.php
Techniques
ignoring refutation
GW deniers often reiterate otherwise-legitimate arguments which have already been refuted, dishonestly repeating them as if those arguments had not yet been addressed.
False dilemma
One of the techniques used by GW deniers is to reduce the problem to an all-or-nothing false dilemma – either:
GW exists and we are causing it and we should take draconian measures to stop it, or else
GW doesn't exist; if it does, it's not our fault; if it's our fault, there's either nothing we can do about it; if there's something we could do about it, the effects won't be that bad if we don't so it's really not worth the fuss.
Any flaws found in the pro-GW fork become, to them, arguments against the whole thing – making this effectively a straw man misrepresentation of global warming advocacy.
winner-take-all thinking
GW deniers tend to take a combative approach to the discussion, trying to undermine GW's credibility without actually addressing the matters of fact it raises; this is in turn fed upon and encouraged by those who like to keep debates stirred up rather than seeking to resolve them.
To counter this, GW proponents might make a set of specific proposals regarding what should be done under various conditions, where the conditions are stated in terms which can be measured. For example, "If a forecast is made which everyone agrees was done using sound methodology, and that forecast shows global temperatures averaging more than 5 degrees above normal over the next 25 years, then we as should be willing to spend at least X dollars of global resources, divided proportionally among the signatory countries by GNP, towards either reversing the temperature change itself or at least ameliorating the effects of said change on the most vulnerable members of our global habitat (to be divided amongst humans and non-humans according to a formula set out in Appendix C etc. etc.)"
Although the core GW deniers might carefully overlook these proposals and shift the debate back to their preferred grounds, it could help clarify the situation for people who are honestly confused about the issue.
[edit] irrelevant accusations
GW deniers often accuse GW advocates of being "alarmists" or fearmongers. This is a bogus accusation on the following levels:
It again deflects attention away from a discussion of the facts (which could be resolved) into a claim of nefarious motives, which is not relevant when the accused have presented extensive facts to back up their assertions.
Fearmongery is only a valid accusation when fear is being used to get people to obey or support a particular group or individual (a technique used shamelessly by the anti-GW Bush II administration). This accusation is more difficult to deflect, though it seems clearly wrong to me. -W..