I don't know a good way to argue with anti-global warming claptrap. Those who opine on the subject from the standpoint of "climate change is a hoax" or "CO2 is a good thing" are trying to pass of their opinions as science and many people are very willing to accept opinions like these because they fit in so nicely with pre-conceived notions. If it's a liberal plot to keep us from enjoying the lifestyle they've worked so hard to have, it's easier to dismiss than if it's a real threat. The fact is, climate change, like most environmental change, is incremental, meaning it's not obvious unless you look over a long time. We have looked long enough, and have reconstructed far enough back to have a great deal of confidence that global warming is happening as a result of anthropogenic greenhouse gas emissions. That's not an opinion, and it's not a condemnation of our lifestyles specifically; it is a fact.
Outdated research is one of the surest signs someone is an anti-global warming climate skeptic, though since global warming is a "liberal academic plot" I'm not sure you'd make much headway citing updated research. It's unfortunate that the IPCC used the Mann, et. al, reconstruction in that first (?) report since it really is fatally flawed (though it's conclusions are correct--in fact, better reconstructions show more warming, not less). Even so, more recent reconstructions using better methods still show the current warming as unusual given the forcings we can measure, and show it occurring rather fast. A good, true multiproxy reconstruction that's more recent than the Mann, et. al, 1999 used by the IPCC that actually shows the climate variability over the last couple of thousand years is the Moberg, 2005 reconstruction.
If you (intrepid readers) are interested in reasons why global warming, and our response to it, is important to consider RIGHT NOW, a book you might think about reading is "Collapse" by Jared Diamond. Some of his examples are questionable (Rwanda being an obvious one), but he does talk about the Vikings living in Greenland, which is frequently cited by climate skeptics as a reason why global warming is a good thing--we could go back to Greenland! He makes a pretty convincing argument that Viking farming practices, in combination with the cooling at the end of the Medieval warm period are really what did the Vikings in. Even without climate change it's pretty evident Greenland is a very marginal environment for a western civilization. The whole point of the book is that it's not so much environmental change that dooms civilizations to collapse, but what societies decide to do in response to environmental limits and difficulties. I personally think one of the hardest things we have to deal with is the human tendency to think that the good times will go on forever (the grasshopper mentality). Every civilization, every population, has the drive to expand to the furthest possible limit. If climate and the water and food supplies that are so critical to living, were constant that wouldn't be a bad thing. Unfortunately, there's a lot of variability to climate that impacts water and food supplies the world over. Additionally, we are pretty sure at this point from both climate reconstruction and from modeling that warming the climate is going to impact water supplies and other environmental variables that impact our ability to produce food. We here in the US I think have largely forgotten that famines can happen. The 1930's are remote, and we've built enough dams and tapped enough aquifers we feel, I think, a tad invulnerable to the impact of our environment. People live by the millions in Phoenix and Tuscon and Los Angeles year-round, isolated from the blistering heat by air conditioning; from lack of water by dams and water projects that pump water from hundreds of miles away to a tap in every home; and from the hunger that most populations face in bad crop years by shipments of food from artificially well-watered central California, Florida, and the Midwest.