The paper by Karl et al. (2015) published in Science on Friday is an ‘express’ report and not up to the standards of a comprehensive paper. It is a highly speculative and slight paper that produces a statistically marginal result by cherry-picking time intervals, resulting in a global temperature graph that is at odds with all other surface temperature datasets, as well as those compiled via satellite.
Key pitfalls of the paper:
* The authors have produced adjustments that are at odds with all other surface temperature datasets, as well as those compiled via satellite.
* They do not include any data from the Argo array that is the world’s best coherent data set on ocean temperatures.
* Adjustments are largely to sea surface temperatures (SST) and appear to align ship measurements of SST with night marine air temperature (NMAT) estimates, which have their own data bias problems.
* The extend of the largest SST adjustment made over the hiatus period, supposedly to reflect a continuing change in ship observations (from buckets to engine intake thermometers) is not justified by any evidence as to the magnitude of the appropriate adjustment, which appears to be far smaller.
Full analysis
