As far as I know, there are no Ph.D.s offered in the study of junk science.  Maybe there should be.  There are numerous instances of credentialed scientists pursuing faulty theories against evidence and common sense.  Irving Langmuir's 1953 talk, "Pathological Science," is a classic compendium of examples; there is the recent case of cold fusion, with the imaginary tabletop nuclear fusion reactors still being given media credibility.

Often media attention and fawning admirers blind scientists to scientific reality.  Junk science also appeals to ideologues if it provides support for their ideology.  For example, those who are ideologically opposed to capitalism are welcoming to science that suggests that corporations are poisoning the food supply or polluting the water supply.

The linear, no-threshold method of evaluating risks from small concentrations of things known to be dangerous in high concentrations is an example of sketchy science that is widely used to promote scares and provide work for regulatory bureaucracies.  For example, the U.S. Environmental Protection Agency has a large campaign against radon, a naturally occurring radioactive gas, tiny amounts of which sometimes seep into houses. 

There is little doubt that large doses of radon cause lung cancer.  Radon is a decay product from uranium, and workers in unventilated uranium mines had high incidences of lung cancer.  However, the government-sponsored campaign against tiny amounts of radon seeping into people's basements does not have solid science backing.  In fact, there is massive evidence that tiny doses of radiation, a part of our natural environment, are not harmful.  The scientist Bernard Cohen discovered that an inverse relationship exists between household exposure to radon and lung cancer.  Yet in the contest between the institutional interests of bureaucracy and good science, good science will always lose.

The biggest junk science fraud of our time is the theory that the increase of CO₂ and certain other "greenhouse gases" in the atmosphere will create dangerous global warming with disastrous results.  Adding CO₂ to the atmosphere probably will cause a small amount of warming, but the empirical evidence is against any disastrous warming.  It is well-established that additional CO₂, a plant food, will increase crop yields and increase crop drought resistance -- certainly not a disaster.  Other popular claims of the global warming tribe -- that sea level will rise greatly, or that weather will become extreme -- are mainly fantasy.

Climate science is a mixture of real science and junk science.  The real climate science knows a lot about climate, but it doesn't know how to predict the future, and it doesn't have a good handle on the effect of greenhouse gases.  The fake "the sky is falling" climate science created a financial and professional windfall for numerous special interests: climate scientists, bureaucracies, politicians, green groups, ethanol producers, and windmill manufacturers, to name a few.  The beneficiaries of this windfall are very protective of their empire.  A climate mafia protects the windfall by suppressing dissent from the global warming party line.  Very few scientists are brave enough and independent enough to publicly dissent.  The scientific organizations that are sensitive to government funding gleefully promote the scare story.  Many climate scientists know full well that a fraud is in motion, but they have no desire to walk into a buzz saw by complaining.

Climate doom predictions are based on very complicated computer models that disagree one with another and that are generally acknowledged to have major shortcomings.  The models predict warming from increased concentrations of CO₂ and other greenhouse gases.  However, major contradictions are given little attention or ignored.  The models are unable to explain the climate history of the 20^th century, even when "calibrated" with speculative inputs.  For example, the considerable warming trend in the early 20^th century, from 1910 to 1940, has never been definitively explained.   It wasn't due to increasing CO₂, because CO₂ was barely increasing during that era.  The only warming trend that could be plausibly blamed on CO₂ was the 1970-1998 warming, but that warming stopped 16 years ago, even though CO₂ concentrations in the atmosphere continued to increase rapidly.  Even scientifically literate people mistakenly assume that climate scientists must be disinterested and know what they are talking about.

The climate bureaucracy depends on the continuing global warming scare for its existence, and those familiar with the ways of government agencies know that a bureaucracy whose existence depends on a problem will always exaggerate the importance of the problem.

In this vein, a National Climate Assessment document has been released in draft form by the climate bureaucracy in Washington.  The document was vetted by a federal advisory committee stacked with global warming promoters; it is 1,100 pages long and mostly lacks serious justifications for its broad claims.  The global warming bureaucrats have entangled critics in a mushy science blob, but the blob has been refuted in considerable scientific detail by a 133-page CATO institute document.

Global warming is global, not something concentrated in the 48 states.  Yet the National Climate Assessment, for propaganda reasons, frames the problem as if it is an American problem.  The Americanization of global warming is carried to the extreme of abandoning scientific convention and expressing temperatures in Fahrenheit rather than Celsius.  In another dumbing-down move, the scientific name "greenhouse gases" is changed to "heat-trapping gases."  Local climate forecasts for the 21^st century are given for 6 different regions of the 48 states, a procedure relying on highly dubious manipulations of similarly dubious global climate model results.

In short, doubt is piled on doubt in order to produce meaningless local climate forecasts.  The report authors think that Americans are scientifically illiterate and uninterested in events outside their immediate environment, so they have warped the report to make it more appealing. 

Although the critical role of China and India in global warming theory is ignored, an entire chapter is devoted to the impacts of climate change on American Indians.  Supposedly, climate change will interfere with catching salmon or the harvest of whales -- presumably important sources of sustenance for Indians not partners in casino enterprises.  For some politically correct reason, global warming promoters always seem to include something about Indians in their pronouncements.

The National Climate Assessment endorses the idea that CO₂ increases extreme weather.  There is little serious evidence to support the increasing extreme weather hypothesis.  Given that climate has random variations as well as systematic natural variations, it is easy to mine the data to come up with evidence for increasing extreme weather in a particular zone, such as the continental U.S. or a smaller zone within the U.S.  There are many types of extreme weather to choose from; thus, by picking over the weather record, one can always find something to support the extreme weather thesis.

However, a major problem with extreme weather theory is that weather is fundamentally driven by the equator-to-pole temperature difference.  The computer models that the believers in global warming use predict that this temperature difference will decrease from global warming.  Thus, logically, global warming should reduce extreme weather, not increase it.

(Incidentally, the phrase "extreme weather" did not begin to appear frequently in New York Times articles until around 2010, when it was starting to become clear that global warming had really stopped, at which point the global warming story was changed to the extreme weather story.)

It is easy to convince people that the weather is becoming more extreme because the most recent weather events are freshest in our memory.  The problem with the "extreme weather from CO₂" hypothesis is that it is basically a convenient invention rather than a scientific discovery.  Speculative scientific justifications can be imagined, but on the whole, the science is missing.  An increase in extreme weather is also missing.

Ten years ago, Senator James Inhofe said on the Senate floor that "man-made global warming is the greatest hoax ever perpetrated on the American people."  Every year that goes by without warming makes Inhofe looks wiser.

Norman Rogers, educated as a physicist, is a retired computer entrepreneur, a volunteer senior policy advisor at the Heartland Institute, and a member of the American Geophysical Union and of the American Meteorological Society.  He maintains a website.