Debunkum- the outing of various false but common beliefs.

The anthropic global warming issue has been widely debunked through the fraud revealed by the emails from the U of East Anglia and the recent revelations about the fraudulent claims of the UN's IPCC. Even India has disavowed the IPCC, led by an "outstanding" Indian scientist. Only Obama and his EPA still claim to believe in AGW.

Heather McDonald of the Manhattan Institute reported on the demise of a favorite social science and liberal trope. The Officer Krupke syndrome has been debunked. This is the theory, popularized in the '60s, that crime results from disadvantages visited upon the criminal class ( "Officer Krupke, we're depraved because we're deprived.")Redistribution of incomes was justified on the grounds of societal good and crime was regarded as a form of social protest.Even police chiefs regarded homicide as a societal problem. Criminologists subscribing to this "root causes" theory predicted that crime rates would go up during the recession. In fact, they went down. This is not to say that there is an anti-correlation; in fact, there is zero effect. Even the prosperous times showed an increase in crime except since the '90s when it crime started declining because of better policing ( shown to greatest effect by Wm Bratton, NYC Police Commissioner under Rudy Giuliani, now being replicated in LA ). Also, there is now clear evidence that increased incarceration has decreased crime for the simple reason that predators have been removed from the streets. This goes against recent budget-driven measures releasing prisoners early.The also-common belief that many inmates are currently only perpetrators of victim-less crimes is belied by the fact that the demographics of prison populations hasn't changed since the '60s.

The panic visited on parents about the supposed correlation between thimerosol in vaccines and autism has been finally put to rest when The Lancet recently retracted its finding of a dozen years ago claiming such an effect ( and causing parents to avoid vaccinating their children!)

Recent years have revealed the utter failure and counter-productive nature of the various New Deal initiatives that were claimed to have ended the Great Depression. We now know that these measures, which the various Obama programs are replicating, were hindrances to the natural recovery of the economy. When Democrat flacks claim that "Obama is the best economic President since FDR" they are only partly correct: he is perhaps the "worst economic President since FDR." The simple explanation is that when the government is anti-business and anti-capitalism, capital goes on strike and business hunkers down. It required WWII to force capital to be deployed and business to expand. Stimulus measures ( "what else does stimulus mean but spending?", said Obama ) don't work when conjoined with hostility to profits and business.

Economists used to talk about "rational economic man" who would calmly optimize his situation. This is also the argument in favor of thinking that the Iranian mullahs would be rational in their use of nuclear weapons since they would be dissuaded, as the more rational Russians and Americans were, by Mutual Assured Destruction. We now know that people are not purely rational in their decisions even when considering only "normal, sane" players. More to the point is the need to consider the decision-making of religious fanatics obsessed with the next world and easily capable of suicide murder and terrorism in this one in order to achieve non-rational goals such as a world-wide caliphate.

Very often debunking is periodic and cyclical, where wrong-headed ideas are shown to be false but then the demonstrations are forgotten and the fallacies repeated.
Go back to the repeated belief that there will be too many people for the planet to be supported. This goes back to Malthus and repeated every generation or so including The Population Bomb of Paul Ehrlich ( one of whose co-authors is now a major adviser to the Obama administration ), debunked most recently by the Green Revolution of Norman Borlaug. Now, of course, it seems that we NEED more population to sustain the Ponzi scheme of American and other social security systems.
Pollution, while it has real aspects, is employed by the "Environmental" movement ( who often elevate the planet above people) to include things which are, rationally, not pollutants at all. That is, acid rain, PCBs and mercury are pollutants. When certain chemicals were demonstrated to deplete the ozone layer, they can legitimately be considered pollutants to be reduced, if not eliminated. When, however, "thermal pollution" of Lake Michigan was adduced as a reason to oppose nuclear plants near the Lake, that was nonsense. Likewise, the EPA's recent categorizing CO2 as a pollutant is nonsense.
Environmentalists seem to need some cause to be angry about ( and often to justify actual terrorist acts against people -- e.g. spiking trees, arson and colliding with whale boats ): the putative endangerment of the polar bear does seem to be debunked by the simple observation that there are, despite ostensible global warming and melting of ice floes, more polar bears than ever. Even when something like DDT was demonstrated to thin out the shells of eagles and similar birds, endangering their survival in certain areas, the countervailing good, such as fighting malarial mosquitoes, was ignored. We now have more eagles but also more people succumbing to malaria than heretofore. It is laughable that millions are being devoted to mosquito netting when pesticide spraying would be much more effective.
Whole philosophies, like Communism and Socialism, have been debunked, only to reappear again and again, most recently in the U.S. The idea of income redistribution is somehow taken as a desideratum without considering that it has never worked and has an enormous downside. It is amusing to note that David Hume referred to "income equalization" as being detrimental to "thrift and industry." Aristotle noted 2500 years ago that, when the hoi polloi in a democracy realize that they can off-load the entire tax burden onto a (voting) minority, the destruction of the polis follows inevitably.