…the hotter it subjectively appears.
The removal of weather-balloon data because poor nations don’t do a good job of minding their weather instruments deserves more investigation, which is precisely what University of Guelph economist Ross McKitrick and I did. Last year we published our results in the Journal of Geophysical Research, showing that “non-climatic” effects in land-surface temperatures – GDP per capita, among other things – exert a significant influence on the data. For example, weather stations are supposed to be a standard white color. If they darken from lack of maintenance, temperatures read higher than they actually are. After adjusting for such effects, as much as half of the warming in the U.N.’s land-based record vanishes. Because about 70% of earth’s surface is water, this could mean a reduction of as much as 15% in the global warming trend.
Another interesting thing happens to the U.N.’s data when it’s adjusted for the non-climatic factors. The frequency of very warm months is lowered, to the point at which it matches the satellite data, which show fewer very hot months. That’s a pretty good sign that there are fundamental problems with the surface temperature history. At any rate, our findings have not been incorporated into the IPCC’s history, and they probably never will be.
