But Jacoby warns that it's dangerous to confuse junk thought solely with ignorance, stupidity, or intellectual laziness "because it is often employed by highly intelligent people to mislead and confuse" those who lack the tools or time -- and all too often the will -- to critically evaluate claims and sources. Of course, the book isn't required reading, and won't be. Pity.

In an earlier column I cited polls by Peter Doran and others at the Univ. of Illinois, Chicago; and Dr. Naomi Oreskes at the Univ. of Cal., San Diego. Both show a clear and growing consensus: climate scientists are telling us human activity is a critical part of global warming. And, more importantly, that our failure to act may well have serious and irreversible consequences.

But most of us aren't climate scientists researching and publishing for peer review by other climate scientists. And most climate scientists are not good about making complex research easy to understand... nor is that their job.

It should be helpful to note professional organizations who support the consensus. Since 2001, 32 National Academies of Science across the globe, from Australia to Zimbabwe -- have issued statements supporting the findings of climate scientists. And there are countless other such organizations who agree.

The American Association for the Advancement of Science says: "The scientific evidence is clear: global climate change caused by human activities is occurring now, and it is a growing threat to society. ... The pace of change and the evidence of harm have increased markedly over the last five years. The time to control greenhouse gas emissions is now." Founded in 1848, AAAS has 262 affiliated societies and academies of science, serving 10 million globally.

In the U.S., among many other respected science organizations making similar statements are the American Chemical Society, American Institute of Physics, American Physical Society, American Geophysical Union, Geological Society of America, National Association of Geoscience Teachers, American Meteorological Society, American Society for Microbiology, and the American Public Health Association.

In contrast, there are the marketers of junk thought.

In earlier columns, I have come down hard on "distinguished" economics professor Walter E. Williams of George Mason University for his and his institution's connections to the oil-rich Koch brothers -- and the Kochs' involvement in "non-profit" front group propaganda.

In his Feb. 5 column Williams used Weather Channel founder John Coleman's "research" showing global warming is a conspiratorial hoax. (Incidentally, The Weather Channel doesn't claim Coleman now, so I guess both he and Williams think the Weather Channel has joined the conspirators.) In the column, Williams accuses professional climatologists and government research organizations of deliberately and dramatically reducing the number of climate monitoring stations in colder regions. They did so, Williams charges, to cook the data and show more warming than was real. Williams is selling junk thought.

I corresponded with David Easterling, Chief of Scientific Services at the National Climate Data Center. He told me, "The number of stations in our big data set does drop off, mainly [because] we can get real time data for only a subset not the entire data set. As for stations in high latitudes, Russia closed a good number of stations due to budget issues following the break up of the former Soviet Union. Canada also has closed some stations due to cost." Now get this:

Easterling continued, "The greatest warming has been in the high latitudes so dropping stations or actually areas with data in high latitudes would lead to less warming in the global temperatures, not more." Just the opposite of what Williams claims.

Jerry Meehl, research scientist at the Climate and Global Dynamics Division, National Center for Atmospheric Research in Boulder, CO, explained: "Bob, the amplification of warming at high northern latitudes has a lot to do with so-called ice-albedo feedback. When you melt a little snow and ice with high reflectivity, more low reflectivity ocean or land is exposed, absorbing more sunlight, heating the surface more, which melts more snow and sea ice, thus absorbing even more sunlight and warming even more to melt more snow and ice, and so on, so that the relative increase in temperature in previously ice or snow-covered areas is quite a bit larger than elsewhere."

Williams says it's all an Al Gore plot. We'll talk more about that.

Graph shows relative percentages and categories who believe climate change is real and that human activity is a contributing factor. From the Doran, et.al. poll at the Univ. of Illinois,Chicago.