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Don’t know much about history, don’t know much about the IPCC


James Hansen and Michael McCracken – two extremely prominent and vocal climate scientists – have rallied behind a US high-school senior who questioned statements in his civics textbook that play up scientific uncertainty on global warming. Now the book’s publisher, Houghton Mifflin, is promising to reassess its accuracy (AP, Dot Earth, Grist, Treehugger). From the AP:

Legal scholars and top scientists say the teen’s criticism is well-founded. They say “American Government” by conservatives James Wilson and John Dilulio presents a skewed view of topics from global warming to separation of church and state. The publisher now says it will review the book, as will the College Board, which oversees college-level Advanced Placement courses used in high schools.

The student, Matthew LaClair, was already an experienced secondary-ed whistleblower, having taped and exposed religious comments his history teacher made in class last year. He contacted the Center for Inquiry, a pro-science think tank, to point out passages like:

“Science doesn’t know whether we are experiencing a dangerous level of global warming or how bad the greenhouse effect is, if it exists at all.”


“The earth has become warmer, but is this mostly the result of natural climate changes, or is it heavily influenced by humans putting greenhouse gases into the air?”

Some wording that LaClair highlighted from the 2005 textbook used in his class was toned down in a more recent edition. For example, “Science doesn’t know whether we are experiencing a dangerous level of global warming or how bad the greenhouse effect is, if it exists at all,” was changed to simply “Science doesn’t know how bad the greenhouse effect is.” Andrew Revkin at Dot Earth parses this:

As we’ve written many times, the climate system’s response to rapidly rising greenhouse gas concentrations remains laden with uncertainty. A doubling of concentrations from the long-term ceiling of 280 parts per million for carbon dioxide before the industrial revolution would most likely raise global temperatures 3.6 to 8.1 degrees Fahrenheit, by the latest I.P.C.C. analysis. So in that legalistic sense, it’s true that science hasn’t defined “how bad” climate change will be.

And that’s about the best you can say of these passages, as Revkin, Hansen, McCracken and the Center for Inquiry all make clear in their point-by-point critiques. A response from Houghton Mifflin posted by Revkin falls well short of addressing the problem: the book’s authors are describing a climate debate that sounds almost nothing like the IPCC‘s painstakingly agreed reports. Instead, as Hansen wrote, “these statements are aimed at giving students the mistaken impression that the scientific evidence of global warming is doubtful and uncertain” – a strategy that’s familiar to Hansen.

Anna Barnett

Photo: dcJohn


  1. Report this comment

    Neil B. said:

    The temperature data over the past several decades look to most people like an upward trend leavened by statistical fluctuation. Not everyone is convinced of course, hence the questions and concerns brought up in the post. I must say, I am impressed anytime a high-school student makes a national splash with a political issue driven by intellectual challenge.

    I wonder if graphing dew point temperatures would show something more definite? It seems that humidity should rise with more evaporation in a warming world. I don’t see much about that in casual perusal of presentation and argument about GW. I wish I could find charts showing dew points over the years, does anyone have data or links or references to same? tx

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    ArndB said:

    Do we know enough about climate history ? Who is going to explain the global cooling from 1940 to about 1970? When will NASA expert James Hansen do it, asks recently.

    Already back in 1981 the James Hansen’s team published their finding that, overall, Earth’s average temperature rose by about 0.4°C for the period from 1880 to 1978, but there was a global cooling from 1940-19701 that he considered subsequently as follows: “I think the cooling that Earth experienced through the middle of the twentieth century was due in part to natural variability,” he said. “But there’s another factor made by humans which probably contributed, and could even be the dominant cause: aerosols.” Meanwhile it is widely claimed that a high concentration of sulphate aerosols in the atmosphere may have had a cooling effect on the climate because they scatter light from the Sun, reflecting its energy back out into space, by industrial activities at the end of the second world war. The way Hansen and his supporting colleagues handle the matter is insufficient for the following reasons:

    The sulphate aerosols relation towards the mid-century global cooling should be checked against three facts, namely

    A. the cooling started with extreme winters in Northern Europe in winter 1939/40; and

    B. the temperatures were low during the winter season, when the effect of sulphate aerosols on sun ray was at the lowest, and thirdly

    C. the pre WWII industrial activities presumably had been much higher than immediately after the end of WWII in 1945]

    More important for understanding the global cooling after 1940 until about 1970 is the impact of the seas and oceans. To understand the extreme cold winters all over Northern Europe from 1939/40 to 1941/42, one has to consider the impact of the North- and Baltic Sea, for the global cooling one should take the North Atlantic and North Pacific into consideration, and what men did do with them during WWII, as thoroughly explained at

    As long as neither J. Hansen, nor IPCC can sufficiently explain the cold war winters in Northern Europe (1939-1942), and the global cooling from 1940-1970 one may wonder about what Hansen wrote (see above): “these statements are aimed at giving students the mistaken impression that the scientific evidence of global warming is doubtful and uncertain”.

    1 David Herring, November 5, 2007, „Earth’s Temperature Tracker“ , NASA at :

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    PaulM said:

    It is Hansen and his team who are presenting the skewed view, greatly overstating the case for man-made warming. What is fascinating (and really quite scary) is that there is an objection to even raising the question “is this mostly the result of natural climate changes,…?”.

    Here is a quote from the British Antarctic Survey website: “…This result suggests that some of the observed change may have an anthropogenic origin, but the lack of a clear and consistent response to changed forcing between models also suggests that much of the observed change in temperatures may be due to natural variability. The IPCC model experiments fail to reproduce some of the observed features, notably the rapid warming of the lower atmosphere. These differences between modelled and observed changes could be used to argue against attributing change to anthropogenic forcing but some caution is called for as the models used may not adequately represent all of the complex processes that determine temperatures in the polar regions.

    I wonder whether that statement will remain on the BAS site, or whether the global warming police will force them to change it?

    Another good example of a teenage whistleblower is Kristen Byrnes.

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    aaron said:

    Yes, the only portion that is spurious is the “if it exists at all” clause.

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