Stuff I Wrote Elsewhere: Water in the Desert Edition

Drier Climate on the Way for Southwest (ad gated):

Climate change is increasing the chances of severe and persistent drought in the Southwest, according to a new report from a panel of federal scientists.
“It’s going to get drier,” said Richard Seager, a climate researcher at Columbia University in New York.
That means diminished water supplies, Seager said.
It is possible that greenhouse-induced drying may have already begun, though the evidence is unclear, according to Seager, one of the report’s authors. “We can’t tell yet,” Seager said in a telephone interview.


  1. John,

    Some of the summaries for these reports get me crazy.

    Will the drying occur in 10 years, 100 years, 1000 years?

    One hundred years ago, cars and electric lights were the new thing, so the timing of consequences is important because society changes.

    Should a reader include the megadrought of 1250 CE, which decimated the human population of the Southwest, as relevant to the conclusions?

    Without real numbers and errors on those numbers–for example

    ‘It has a 50 percent chance to get drier (and a 50% chance to get wetter) in the next 200 (+/-300) years’

    — is the conclusion of some of these reports. To me this conclusion, however well documented, says

    ‘We don’t know what will happen, but please continue to pay our salaries for the next 20 years until we can retire.’

    The EPA’s report on benzene hazards in Houston can be summarized as

    “If even a single person, somewhere in the Houston area (3,400,000 people), gets a leukemia and dies and this leukemia might be associated with benzene, then the $5,500,000 that that person’s life was worth is more than the salaries of the people who made this report, so the Clean Air Act is a good thing.’

    The studies come across as fear mongering in support of getting a salary more than they come across as actionable items. I am annoyed at the benzene study because it took me 100 pages of reading, including appendices, to be sure that the conclusion was based on one or two people somewhere in Houston dying from leukemia at some point in the next 50 years.

    Cigarette smoking, on the other hand, is a real risk and needed its regulation.


    I would really commenters to discuss error bars on the scientific conclusions of similar reports and the effects of the variables that were not studied.

    For instance, in the benzene report, the effects of low levels of benzene on human leukemias was estimated not measured, non-linear effects were ignored, threshold effects were ignored, changing technology was ignored, and the ability of people to move away from a place that smelled of benzene was ignored. Also, compliance to regulations was assumed to be 100%.

    All of these assumptions, down in the fine print of the report, make the executive summary conclusion no longer credible, at least to me. Stated differently, the report seems to say that the 97% confidence interval for the leukemia death rate from benzene exposure in Houston lies between -7 (seven people get healthier from benzene exposure) to 30 (thirty people die not the two people estimated in the report). Since -7 is not politically correct, the minimal allowable number is 0 meaning that benzene does not induce any extra leukemias, a non PC conclusion. The minimal PC conclusion seems to be one extra person dies. This is the conclusion of the report.

    What drove me to the above rant is not only my annoyance with the science of these reports, it is also that I could have spent the time that it took me to understand the report much more profitably by biking or welding. 😉 So the reports not only said nothing but wasted my time in reading them.

    Precis- error bars are critical in making conclusions that are not just current political orthodoxy sprinkled with a frosting of numbers.

  2. John – have you ever talked to Dr. Grant Meyer at UNM about the work he does on the sediment records of forest fires? Grant’s an old friend of mine, and every time I read discussions of drought and climate change in the SW, I think of his work.

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