Planet Gore

Paging Dr. Hansen . . .

You gotta love Google alerts. I’ve read the UK’s spiked before (Brendan O’Neill mostly), but it’s not a daily stop. Today it’s certainly worth a visit, as they apply a little logic and “maths” to James Hansen’s claims about man-made global warming; our NASA pal comes up wanting.
Canadian contributor DK Johnston examines Hansen’s “99-percent certainty” that GHG emissions must be reduced in order to combat global warming (and the underlying assumptions of that claim). Johnston’s handicapping puts the certainty at more like 35 to 70 percent.

People are notoriously error-prone when reasoning about probability. When told that two statements are each very likely to be true, most people immediately conclude that the two taken together are just as probable. But this isn’t so. Claiming that two things are true just gives you twice as many opportunities to be wrong. Uncertainties multiply, however slight each individual one might be.


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