The article fails to mention that pre-1900 temperatures are not accurate global averages. They are rough estimates of the Northern Hemisphere average based mainly on weather stations in the US and Europe. Southern Hemisphere coverage is sparse. In addition, there are more guesses (aka "infilling") than actual data. In fact, the global average temperature can not be accurate until the use of weather satellite data in 1979. Those data only require a small amount of infilling over both poles. The NASA-GISS surface numbers still have too much infilling and the people collecting the data are pro-warming biased and can not be trusted. They arbitrarily deleted significant global cooling measured in the 1940 to 1975 period, as reported by NCAR in 1975. It was "inconvenient" to have global cooling when the CO2 level was rising. That did not support the more CO2 causes global warming narrative, so the cooling magically "disappeared".
FULL ARTICLE HERE::
Note that the Guardian article cites:
“The average temperature in 2019 was about 1.1C above the average from 1850-1900, before large-scale fossil fuel burning began.”
The entire graph and temperature data set from NASA GISS is displaying just a small change of 1.1°C of temperature, which is highly magnified to show the trend. Because this small temperature change is magnified, it gives the false impression of having a steeply rising slope. For the unobservant, that steep slope looks like a dangerous trend that would constitute a “climate emergency”.
Note the two graphs below. Figure 4 shows how global warming is depicted in the media from NASA GISS data (such as seen above in the Guardian article), plotting a narrow temperature range to show a magnified graph.
Figure 5 below shows the exact same data when plotted on the scale of human temperature experience, such as the range of temperature we experience yearly from winter to summer. This is done by removing the anomaly calculation from the GISS data, using the agreed-upon baseline temperature:
For the global mean, the most trusted models produce a value of roughly 14°C, i.e., 57.2°F
GISS Surface Temperature Analysis, NASA [Note: This page was updated on 18 March 2022. It would appear the quote above may have been amended to read “they often used a baseline of about 14°C (following Jones et al, 1999)”]
Simply using an Excel Spreadsheet allows us to add that 57.2°F temperature back to the NASA GISS anomaly data value. You can download and examine the spreadsheet here: GISSinabsolute2020.xlsx or Download
The result of that process gives you Figure 5:
Figure 5 shows a slow, and gradual temperature rise in actual absolute temperatures over the last 140 years. The difference with Figure 4 is striking and doesn’t look alarming at all.
If you were presented with Figure 5 as proof of an impending “climate emergency” would it be as concerning as Figure 4 or the NASA GISS graph commonly cited in the media?
In the article Lessons on How to Lie with Statistics by Will Koehrsen Jul 28, 2019, he makes the following point:
How to Lie with Statistics2 is a 65-year-old book that can be read in an hour and will teach you more practical information you can use every day than any book on “big data” or “deep learning.”
Always Look at the Axes on a Chart
Adjusting the axes of a graph to make a point is a classic technique in manipulating charts. As a first principle, the y-axis on a bar chart should always start at 0. If not, it’s easy to prove an argument by manipulating the range, by, for example, turning minor increases into massive changes:
Lessons on How to Lie with Statistics, Will Koehrsen, 28 July 2019