The non-Paradox of Consensus

This essay has appeared, or reappeared; it looks like it was first published some years ago. It concludes, paradoxically:

“In our view, the fact that so many scientists agree so closely about the earth’s warming is, itself, evidence of a lack of evidence for global warming.”

The argument that leads to this conclusion is not clearly laid out and verges on complete incoherence. Nevertheless, some people seem to find it meaningful, so I thought I would look at it in more detail.

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Six of one; half a dozen of the other

Occasionally, I see it stated that averaging of repeated measurements only reduces the uncertainty if they are repeated measurements of the same thing.

This is simply not true.

It is, however, a good place to start thinking about the general problem. If we take three measurements of (say) the temperature of a water bath M1, M2 and M3, the average is (M1+M2+M3)/3.

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November 2015

Globally speaking, November was a warm month, at least for a November. GISTEMP, NOAAGlobalTemp and HadCRUT4 all have November as the warmest November on record nominally. Part of the warmth, at least the part that distinguishes it form 2014, say, is likely due to the El Nino that matured mid-year. There are various estimates of the effect that El Nino has on monthly temperatures (directly because the El Nino region is rather large and part of the surface and indirectly because El Nino warms other areas with some lag) but are around a tenth of a degree or so. Continue reading

December 2015

December 2015 was the last month of 2015. It had 31 days. December was also an unusually warm December, globally. The temperature anomaly in December was the highest recorded by some margin. In the NOAAGlobalTemp analysis the margin was 0.29degC. In HadCRUT4, it was around 0.31degC. Uncertainties in monthly values are typically larger than they are for annual values, but even so, the margin is significant in so far as the 95% uncertainty ranges for this December and the previous record holder don’t overlap. Continue reading

Drifting buoys and Argo floats are not the same thing

A drifting buoy drifts around at the surface of the ocean. Most measure pressure, sea-surface temperature and, by their changing position, ocean currents:

An Argo float drifts around at depth (usually 1000m), periodically diving down to 2000m and then rising up to the surface measuring temperature and salinity profiles as they go. They then sink back to 1000m and wait till the next cycle, which typically has a 10-day repeat.

March 2015

El Nino conditions continued to develop through March and into April. NOAA declared an ‘official’ El Nino, but the Bureau of Meteorology as of the time of writing (25 April) had not. The sea surface temperatures are indicative of a weak El Nino and the atmospheric part of the ENSO cycle has become more prominent unlike last year’s El Ninito. Continue reading


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