The Curious Case of the Missing Data – Watts Up With That?

Ivor Williams

I shall end with two unanswered questions. The reason for that lies in a story with eight decimal places of recondite mystery and scarcely believable deductions. One last glimpse of reality: the mean temperature of the world at the moment (early November) is hovering around 14 deg C, which is never used because it does not convey a sufficient element of danger in the global warming message. Fourteen degrees Celsius or fifty-seven Fahrenheit are not messages of imminent doom. Either one is the annual mean temperature of Bordeaux, San Francisco or Canberra.

Therefore the Wise Ones have decided that any global temperature given to the masses must always be shown as a difference from the mean of the half-century 1850-1900, which, they say, is representative of our world in smoke-free pre-industrial times. That period also happens to be towards the end of the Little Ice Age, which, the Met Office says, had ‘particularly cold intervals beginning in about 1650, 1770 and 1850.’ Cold spell beginning in 1850? Interesting.

Thus it was that on 10 January this year the Met Office told us that ‘The global average temperature for 2024 was 1.53±0.08°C above the 1850-1900 global average,’ This  is an extraordinarily accurate figure but the World Meteorological Organisation has much the same: ‘The global average surface temperature [in 2024] was 1.55 °C … ± 0.13 °C … above the 1850-1900 average, according to WMO’s consolidated analysis.’ Ignore the scarcely believable accuracy of those second decimal places, there’s worse to come.

The obvious question is: Why were those fifty years chosen as the fundamental reference period? The answer is easily found: ‘Global-scale observations from the instrumental era began in the mid-19th century for temperature,’ says the Intergovernmental Panel on Climate Change (IPCC) in their Fifth Assessment Report (Section B, page 4.) An associated IPCC Special Report (FAQ1.2 para 4) explains that ‘The reference period 1850–1900 … is the earliest period with near-global observations and is … used as an approximation of pre-industrial temperature.’ Note the categoric statements that sufficient data is available in that nineteenth century fifty-year period to calculate the global mean temperatures.

In 1850, may I remind you, Dickens was writing David Copperfield, California was admitted to the Union as the 31st state and vast areas of the earth were still unexplored. 1900 brought the Boxer Rebellion (China), the Boer War (South Africa) and the Galveston hurricane (USA). There were still quite large areas awaiting intrepid explorers.

I was curious about how in olden times those global temperatures were actually measured, but after a painstaking search of websites and yet again proving that AI-derived information can be both wrong and misleading, I turned in despair to the Met Office enquiry desk. Their reply was long and very detailed. No actual data, but several clues as to where to search. Very interesting clues.

The IPCC report above claiming ‘global-scale observations’ is obviously true, because the World Meteorological Organisation has a comprehensive graph showing six different global mean temperature measurements of the difference from the 1850-1900 period. But a link ‘Get the data’ on the same page leads to the following curious table of the Met Office anomalies:

1850  -0.1797
1851  -0.0592

then every year to

1899  0.0128
1900  0.1218

then every year to

2023  1.4539
2024  1.5361

There is even more accurate Met Office data from the past, this time anomalies relative to the 1961-1990 period but this time totally unbelievable, all from HadCRUT5.1.0.0, Summary Series, Global, CSV file, Annual.

1850  -0.42648312
1851  -0.2635183

then every year to

1899  -0.34430692
1900  -0.2301605

then every year to

2024  1.1690052

Dig further and monthly values are produced. You can’t help being suspicious of even two decimal places, let alone eight. I dug deeper. I found graphs.

They show northern and southern hemispheres separately, with both station count and coverage percentage. They are from a paper: Hemispheric and large-scale land surface air temperature variations: An extensive revision and an update to 2010, P.D. Jones et al. Page 48, line 1120. They show the number of recording stations and the hemisphere percentage covered from 1850 to 2010.

Very similar pictures are also shown in Land Surface Air Temperature Variations Across the Globe Updated to 2019: The CRUTEM5 Data Set, T J Osborn et al, para 5.1 fig 6, and Hemispheric Surface Air Temperature … to 1993, P D Jones 1993, page 1797.

Approximate readings from the above graphs:

1850
Northern hemisphere coverage          7%
Southern hemisphere coverage         0-1%

1900
Northern hemisphere coverage          23%
Southern hemisphere coverage         6%

Surely not? There must be a mistake somewhere. But there’s nothing like a graph in scientific peer-reviewed papers for providing clear and unequivocal information. If you still think this just cannot be true, then look further at the American Meteorological Society map of station density 1861-1890 (Section 5 of Journal), or a classic Bartholomew map of world reporting stations in 1899.

The information supplied by the Met Office led me to a meandering pathway of scientific papers covering thirty-odd years of intensive research into the problem of accurately measuring global mean temperatures from 1850 onwards. The path seems to have ended in a swirling fog.

Those graphs show that even by 1900 only about 15% of the earth had recording stations. And the 1850 data is apparently extracted from only around 4%.

How can world temperatures be measured that accurately with such an impossibly small amount of data – almost nothing from the oceans and most of the rest from North America and Western Europe?

It wouldn’t really matter except for someone having decided that current global mean temperatures should always be shown to the worried world as anomalies compared with the 1850-1900 data, which is itself possibly a cooler climatic period. The intention must be to demonstrate clearly that there is no doubt that we are indeed warming up dangerously, and if we don’t do something about it soon it will be too late and don’t say we didn’t warn you.

But, and this is one huge ‘but’, how can the 1850 mean global temperature be recorded, for instance, as -0.1797 deg C less than the mean of 1850-1900, when it seems that reporting stations covered only about 4% of the earth at that time? And why to a totally unrealistic ten-thousandth of a degree?

I did warn you this would end with two unanswered questions, and here they are, both about that fifty-year 1850-1900 period:

Where can we consult the actual original global data?

How were those incredibly accurate anomaly figures calculated?