Just in time for the massive protest by Dutch farmers against greenhouse gas regulations that will put an estimated one-third of them out of business, a new study by Dutch computer scientists shows that while the Netherlands has warmed (drum roll please...) much faster than the global average, it’s all due to a change in wind patterns that drew more warm air over the country in recent decades. After taking account of this effect and changes in the sun, they found that the role of carbon dioxide was precisely zero. And since we’re going full denialist here, let’s make sure we explain that the authors (Jippe Hoogeveen and Han Hogeveen) are real computer scientists at a real university (Utrecht) and the paper was published in the prestigious International Journal of Climatology, which is published by the UK Royal Meteorological Society. After checking and re-checking their results, and looking for any possible way of boosting the greenhouse role, they conclude: “Interestingly enough, CO2 does not seem to play a role.” Except in convincing politicians to enact policies that throw people out of work. Including, sometimes, the politicians who did it, we might add.
The authors noted that warming in the Netherlands was not gradual, like the rise of CO2 in the atmosphere, instead it happened unevenly, such as in a big jump in the 1980s. They also noticed that the weather in the Netherlands is strongly affected by which direction the winds are coming from. So they dug into historical records and found daily charts of wind speed and direction back to the 1830s. From these they isolated 24 main weather patterns that are formed depending on which way the wind is blowing. From these records, plus data on solar irradiance and cloud coverage they constructed a model to explain mean annual temperature in the Netherlands. The result was astonishingly accurate.
The black line is the observed temperature record and the red line is the prediction from their model (“WP” stands for “Weather Pattern”). Note that greenhouse gases were not used in the model. When they added CO2 it did nothing to improve the fit: the parameter for CO2 was zero. When they tried to force it into the model anyway, using standard assumptions about how big an effect CO2 should have, the model got noticeably worse and overpredicted warming. Then they checked if CO2 might explain the warming in the places the wind was coming from, but that didn’t work either.
In fact the authors went to considerable lengths to get CO2 into the model, with no success. One of the most convincing tests of their model was that it could explain the jump in climate conditions in 1988. After taking account of the shift that occurred that year in prevailing winds, there was nothing left over for CO2 to explain. They tried several experimental data processing methods and each time CO2 added nothing, leading them to remark “we can conclude that our method has not incorrectly underestimated the influence of CO2.”
The authors then remark that their analysis should be done for other regions of the world as well. In principle, if wind patterns change so that parts of Europe and North America are awash in southern rather than northern winds for more of the year than previously, it will show up as “warming” in the global temperature records even if there is no more heat than before, it’s just spread out differently. No doubt the IPCC will get right on it. Just as soon as the Dutch government apologizes for putting all those farmers out of business. Or they put it out.