Thursday, March 31, 2011

The Perils of Pop Sci

"NASA Study Acknowledges Solar Cycle, Not Man, Responsible for Past Warming" is the headline claim of a Daily Tech story. Reading the finer print, however, one learns that a Goddard Space Flight Center report concluded, merely, "that solar variation has made a significant impact on the Earth's climate."

This more specific information does not quite confirm the impression given by the heading that solar variation "Not Man, Responsible for Past Warming," but the article's penultimate paragraph leaves no doubt that the implication of the heading was intended:

While the NASA study acknowledged the sun's influence on warming and cooling patterns, it then went badly off the tracks.  Ignoring its own evidence, it returned to an argument that man had replaced the sun as the cause current warming patterns.  Like many studies, this conclusion was based less on hard data and more on questionable correlations and inaccurate modeling techniques.
But is this so?

Not according to Science Daily, an online publication of the American Association for the Advancement of Science, which in an article referenced in the Daily Tech story, states:

...scientists have learned that about 1,361 watts per square meter of solar energy reaches Earth's outermost atmosphere during the sun's quietest period. But when the sun is active, 1.3 watts per square meter (0.1 percent) more energy reaches Earth. ...

... Over the past century, Earth's average temperature has increased by approximately 0.6 degrees Celsius (1.1 degrees Fahrenheit). Solar heating accounts for about 0.15 C, or 25 percent, of this change, according to computer modeling results published by NASA Goddard Institute for Space Studies  ...
 So who are you going to believe?

Daily Tech has an ethics policy which ..."prevents external forces from influencing the website’s content and keeps articles unbiased and accurate,"a statement of such absurd epistemic self-confidence that I'm inclined to go with the Triple-A S. But in any case, this seems a good time to review Bertrand Russell's rules of scepticism:

The scepticism that I advocate amounts only to this:
(1) that when the experts are agreed, the opposite opinion cannot be held to be certain;
(2) that when they are not agreed, no opinion can be regarded as certain by a non-expert; and
(3) that when they all hold that no sufficient grounds for a positive opinion exist, the ordinary man would do well to suspend his judgment.
These propositions may seem mild, yet, if accepted, they would absolutely revolutionize human life.
 Here, of course, we are not dealing directly with the opinions of experts but with what science journalists would like one to believe are the opinions of experts, something that Russell would surely have urged one to discount altogether.

First posted by The Inexact Scientist

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