An article in German presents the problem:  “Warmer than at any time since records began …” – The fraud with the reference period.”  LackmustestTester at reddit provides an English synopsis explaining the serious issue of global temperature records lacking prior to 20th century. Excerpts in italics with my bolds and added images. The original in German is here.

Temperature Records Lacking Before Last Century

Well, Copernicus, as an organization financed and probably also controlled by the EU, is one of those organizations that boast about data transparency. So we have obtained the data that Samantha Burgess refers to in her heat record letter, which you can get here, and counted out which measuring stations in which parts of the world are the basis for the global average temperature calculated for the years 1850 to 1900, which serves as the basis for the alleged increase of 1.46 degrees Celsius.

Well, let’s say right away that China and Southeast Asia are completely irrelevant for the global temperature from 1850 to 1900; neither China, Japan, India, Thailand, Indonesia and the Philippines, to name but a few, appear in the “reference period from 1850 to 1900” with even a single measurement date.

But that’s not all: the global temperature, calculated for the pre-industrial period from 1850 to 1900, which has become the basis for all claims about the significant increase in temperatures, does not include any data from not only Asia, it does not include any data for South America and Africa has shrunk to Algeria, Morocco, Tunisia and Egypt in the north, and South Africa in the south.

The earth temperature of the reference period 1850 to 1900 is essentially a North American temperature, which is primarily based on measurement data from the USA: 83.4% of the temperature data for the “global temperature” of the “reference period 1850 to 1900” for the northern hemisphere originate from the USA, 75.9% of all measuring stations on the basis of which the global temperature of the “reference period 1850 to 1900” is calculated are located in the USA, and just under 10% in Canada.

Not only to conceal this bias in the data basis, but also to
pass off the temperatures calculated for the “reference period
from 1850 to 1900” as “global temperatures” is fraud.

Another way to show the bias of the data, on the basis of which one can at best make statements about the USA and Canada, is to differentiate the measuring stations into those located in the northern hemisphere and those located in the southern hemisphere. The following figure shows, among other things, the result of this comparison.

Number and locations of the measuring stations used to calculate the reference period 1850 to 1900 – blue: NH, orange: SH, grey: only US, red: cumulative values

Just 9% of the measuring stations on the basis of whose data the temperature of the reference period 1850 to 1900 is calculated, as a measure of the pre-industrial temperature that is so important for the climate cultists, are located in the southern hemisphere and there they are mainly found in Australia, apart from a few scattered measuring stations in South Africa and two measuring stations in Sri Lanka.

The Earth’s temperature is obviously a temperature that can be
calculated independently of local temperatures in India, China,
Southeast Asia, South America and large parts of Africa.

If it is possible to calculate the Earth’s temperature for the period from 1850 to 1900 without taking large parts of the Earth into account, then the question arises as to whether it is possible to do without any measurement data at all, especially as their distribution over the years is very uneven: a total of 32 measuring stations form the basis for the global Earth temperature calculation for the years 1850 to 1859, with a further 62 from 1860 to 1869. As the figure above shows, the claim that the entire period from 1850 to 1900 is a reference period is simply fraudulent, as 77% of the measuring stations were only put into operation after 1890.

This is all a huge humbug that ultimately represents scientific fraud, and anyone who compares today’s data with the data from the reference period 1850 to 1900 and claims to be able to extract any information about the development of the global earth temperature from this is either out of their depth or a climate fraudster.

Footnote from Comments

The official record Copernicus uses goes back to 1940.

Additionally, it appears that at least the NH was just emerging from a prolonged cold period – the little ice age – which would assist in providing for the lower baseline temps. All in all, it seems silly to try and make such comparisons, and even when they are done we seem to run into ‘re-analysis’ of past temp data that persistently cools the past data sets, which of course make current temps seem warmer.

It’s not only NOAA doing these adjustments, German DWD does the same thing. They also placed new stations at inappropriate sites and reduced the number of stations.

Consider the Hot Air in recent claims like these:

Humanity has just lived through the hottest 12-month period in at least 125,000 years CNN

Earth posts hottest 12 months on record and probably 125,000 years Washington Post

This year is “virtually certain” to be the warmest in 125,000 years said E U scientists Reuters

The hottest temperature that our planet has experienced in something like 125,000 years Scientific American

Earth just had its hottest year on record — climate change is to blame Nature