by K. Hansen, Apr 15, 2025 in WUWT
Looking over one of my earlier essays, I found a note pointing to a very interesting journal paper whose findings raised an important question. The paper is not new, it is almost a decade old: “Spatiotemporal Divergence of the Warming Hiatus over Land Based on Different Definitions of Mean Temperature”; Zhou & Wang (2016) [ pdf here ].
The paper was looking into this issue, as stated in the introduction:
“Despite the ongoing increase in atmospheric greenhouse gases, the global mean surface temperature (GMST) has remained rather steady and has even decreased in the central and eastern Pacific since 1983. This cooling trend is referred to as the global ‘warming hiatus’.”
We can see what they were concerned about with in this graph:
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Bottom Line:
1. Methods and definitions matter and can change our understanding of claimed rates of change of Global Mean Temperature. As covered in my series “The Laws of Averages”, not all averages give the same result or the same meaning. Some averages obscure the physical facts.
2. “…the use of T2 may bias the temperature trend over globe and regions” and “the sharp faster warming in the highest northern latitudes is greatly reduced” by using T24 to calculate warming trends.
3. Zhou and Wang recommend using the Integrated Surface Database-Hourly (ISD-H, [T24])available from NOAA.