The 50-50 Argument

It’s not logical to state that most warming since 1950 has been caused by man (or Mann):

The glaring flaw in their logic is this. If you are trying to attribute warming over a short period, e.g. since 1980, detection requires that you explicitly consider the phasing of multidecadal natural internal variability during that period (e.g. AMO, PDO), not just the spectra over a long time period. Attribution arguments of late 20th century warming have failed to pass the detection threshold which requires accounting for the phasing of the AMO and PDO. It is typically argued that these oscillations go up and down, in net they are a wash. Maybe, but they are NOT a wash when you are considering a period of the order, or shorter than, the multidecadal time scales associated with these oscillations.

Further, in the presence of multidecadal oscillations with a nominal 60-80 yr time scale, convincing attribution requires that you can attribute the variability for more than one 60-80 yr period, preferably back to the mid 19th century. Not being able to address the attribution of change in the early 20th century to my mind precludes any highly confident attribution of change in the late 20th century.

In other words, we shouldn’t and can’t have as much confidence as many would like to push their policy agenda.

One thought on “The 50-50 Argument”

  1. Good work, Rand. I see you have Jim “pinned down” on the IRS-gate thread, and your “Climate Change” thread is free and clear . . .

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