As the United Nations Intergovernmental Panel on Climate Change (IPCC) issued yet another report warning that stopping alleged global warming is, in the words of the Associated Press, a “life-or-death” matter, an Australian researcher released his own report showing that the data on which the IPCC’s alarmist claims are based is so overwhelmingly faulty that it is “not fit for global studies.”
Climate-data researcher Dr. John McLean performed what is believed to be the first-ever audit of the primary global temperature dataset used by the IPCC, known as HadCRUT4. Yes, you read that correctly: In all the years climate alarmists have been relying on HadCRUT4, no one ever bothered to examine the data to determine whether it was accurate and reliable. According to McLean, “It is neither of those things.”
McLean found more than 70 problems with the data, including “simple issues of obviously erroneous data, glossed-over sparsity of data, significant but questionable assumptions and temperature data that has been incorrectly adjusted in a way that exaggerates warming.”
Among the “obviously erroneous data”: a Colombian town that recorded average daily temperatures above 80 degrees Celsius (176 degrees Fahrenheit) for three months; a Caribbean station that twice reported an average temperature of zero degrees Celsius (32 degrees Fahrenheit) over the month of December; and a Romanian city that claimed an average September temperature of -45 degrees Celsius (-49 degrees Fahrenheit). “On top of that,” added McLean, “some ships that measured sea temperatures reported their locations as more than 80km [50 miles] inland.”
Another major problem with the data is the lack thereof, wrote McLean:
The dataset starts in 1850 but for just over two years at the start of the record the only land-based data for the entire Southern Hemisphere came from a single observation station in Indonesia. At the end of five years just three stations reported data in that hemisphere. Global averages are calculated from the averages for each of the two hemispheres, so these few stations have a large influence on what’s supposedly “global.” Related to the amount of data is the percentage of the world (or hemisphere) that the data covers. According to the method of calculating coverage for the dataset, 50% global coverage wasn’t reached until 1906 and 50% of the Southern Hemisphere wasn’t reached until about 1950.
In May 1861 global coverage was a mere 12% — that’s less than one-eighth. In much of the 1860s and 1870s most of the supposedly global coverage was from Europe and its trade sea routes and ports, covering only about 13% of the Earth’s surface. To calculate averages from this data and refer to them as “global averages” is stretching credulity.
Furthermore, adjustments to historical temperatures “show an exaggerated warming trend,” McLean found. Frequently, thermometers are moved because of urban buildup around them that is causing them to report temperatures that are too high. Present-day climate researchers assumed, first, that every instance of a thermometer move in the historical record happened because of inordinately high temperature readings and, second, that the thermometer had always registered too high (rather than slowly becoming inaccurate over time). They then subtracted a fixed number of degrees from all temperatures recorded before the move — and did so again on all subsequent moves of the same thermometer. Needless to say, this approach makes temperatures from earlier periods look much cooler in comparison to today’s temperatures, giving an appearance of rapid global warming.
McLean concluded that “the dataset shows exaggerated warming and that global averages are far less certain than have been claimed.”
“Ultimately,” he averred, “it is the opinion of this author that the HadCRUT4 data, and any reports or claims based on it, do not form a credible basis for government policy on climate or for international agreements about supposed causes of climate change.”
Despite the fervent wishes of global-warming believers, McLean cannot be dismissed as a mere “climate denier.” “In March 2016,” noted Breitbart’s James Delingpole, “he advised [the Hadley Center, source of the HadCRUT4 data, and the U.K. weather bureau] of certain errors which they promptly corrected. So he’s an authority they take seriously.” But will they take him seriously enough to reexamine all their data and dial back their alarmist forecasts?