The Crisis Report - 03 : How much has the Earth warmed up since the “preindustrial” period?

Surprisingly it’s hard to get a straightforward answer to that question.

Our world is warming up, rapidly

“Everybody talks about the weather, but nobody does anything about it.”

1887 Charles Dudley Warner

With Global Warming the situation is slightly different. Everyone knows it’s getting hotter, but no one seems to know how much it’s warmed up or how hot it’s going to get.

Some of this confusion is excusable. We are flying blind at this point. Atmospheric CO2 levels are now higher than they have been in millions of years.

In the past 800,000 years, CO2 levels never exceeded 300ppm

So, we literally do not know what's going to happen. Considering that we are talking about the global climate system that all of us depend on to maintain the habitability of the planet and provide us with food, caution would seem to be an appropriate response.

Since we all know the sad history of the “Climate Culture Wars” and still have to live with the cretinous stupidity of White Trumpublican America, I will forego recounting how we have arrived at this point. What’s done is done, elections had consequences. At this point we need to concentrate on managing the damage and surviving the climate disaster that is speeding towards us.

To that end, it would seem that the most basic starting point for going forward, would be knowing how much damage has been done. How much hotter has the Earth gotten since 1850, when the atmospheric concentration of CO2 was 280ppm?

Surprisingly, it’s hard to get a clear, straightforward answer to this question.

For example, consider this article by NASA published in 2021.

Global Temperature Anomalies from 1880 to 2020

In it they say, first this:

“the year’s globally averaged temperature was 1.84 degrees Fahrenheit (1.02 degrees Celsius) warmer than the baseline 1951–1980 mean, according to scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York.”

And then they say this:

“Earth’s average temperature has risen more than 2 degrees Fahrenheit (1.2 degrees Celsius) since the late 19th century.”

So, how much as the Earth warmed up?

The second statement has become the accepted measurement quantifying “global warming”. It’s 1.2℃. Look at any mainstream press article discussing global warming or climate change and that’s the number they all use.

However, when you try to tie the two statements together it seems like something is off. How can warming “since the late 19th century” be 1.2℃ and warming since 1980 be 1.02℃? The implication is that almost no warming happened between “the late 19th century” and 1980 and then a massive amount of warming happened since then.

Actually, that’s exactly what the head of the GISS has stated in defense of the 1.2℃ measurement. Saying that approximately 70% of global warming has happened since 1980 and, that although it appears there has been a 1.1 increase in the Global Mean Temperature since 1980, the actual number is probably less.

This is a very carefully worded, very carefully nuanced argument that appears to say something but is nebulous. It is more like “political-ese” than anything scientific and unfortunately it has become the norm in the highly toxic, politically charged field of climate science.

The question is, since 9 out of 10 of the hottest years on record happened between 2010 and 2020, does it make sense?

Anomaly in this case is how much hotter a year was than the 1950–1980 modern baseline

How 1.2℃ became “the number” and why it’s almost certainly too low, the politics of Climate Change.

Just like the CDC before the pandemic, the GISS has long had an excellent reputation for doing good “politically neutral” science. So, if they say that global warming since “the late 19th century” has increased the Earth’s GMT by 1.2℃, most people would be inclined to believe them.

They get additional credibility because they are constantly attacked by Climate Change Deniers, including Senator Ted Cruz, who accuse them of manipulating the data to inflate the amount of global warming that’s occurring. If the Climate Deniers are constantly howling that the GISS numbers are at least 50% too high, the implication is that they have resisted political pressures and their analysis is sound.

But is this true? Where does the 1.2℃ number come from, and why have they shifted from using 1850 as the baseline to using the nebulous “late 19th century”?

140 years of GMT readings, temps are anomaly’s above or below the modern baseline

Based on the dataset depicted above, how much would you say the Earth has warmed in the last 140 years?

It’s clear that between 1980 and 2020 there was roughly 1℃ degree of rapid warming.

NOAA and GISS both state that warming between 1981–2010 averaged 0.18℃ per decade (roughly 0.54℃ of warming). So, how do you square that with the statement that the total warming since 1880 has been only 1.2℃?

All you have to do is draw a line.

Look! Only 1.2℃ of warming over 140 years. Just 0.08℃ per decade, nothing to worry about

Now, if you have been following the global warming issue for decades this seems both ridiculously simplistic and highly suspicious. The choice of 1880 as a baseline is a huge red flag if you are familiar with the climate history of the 19th century.

Because, 1880 was the hottest year of the entire 19th century!

It was the climax of a massive El Nino event and temperatures soared to record levels across the globe. If you zoom out a bit this is clearly visible.

1880 is about 0.5℃ hotter than 1850

Here’s another dataset as well:

This is from a European Climate Agency 2018 report — the 1880 temperature spike is easily seen

By using 1880 as your “late 19th century” baseline, you reduce the amount of global warming by roughly 0.6℃ or about 30%.

It goes from a “crisis level” of 1.8℃ that requires immediate large-scale reductions of fossil fuel use, to a “concerning level” of 1.2℃ that makes “the goal of 1.5℃” difficult, but not impossible, to achieve.

Using 1880 as your baseline and then claiming that that there has been only 1.2℃ of warming “since the preindustrial” era is what analysts call a “true lie”.

While it is factually true, it is so misleading and deceptive as to be a lie. Since most people have no context for judging the accuracy of that number, they are likely to accept it uncritically.

As an analyst, I am appalled and saddened that GISS, and NOAA are promoting the narrative that global warming is 1.2℃. As a realist, I understand the dynamics of that decision.

If you were unaware that the baseline for measuring “climate sensitivity” had shifted from 1850 to 1880 that’s because it hasn’t. The last major study published in 2020 (An Assessment of Earth’s Climate Sensitivity Using Multiple Lines of Evidence) continued to use 1850 and a CO2 level of 280ppm as the baseline for projecting the warming effect of doubling atmospheric CO2 to a level of 560ppm.

All of the models done since the 70’s use 1850 as the starting point for measuring the effects of increasing levels of CO2 in the atmosphere.

For decades 1850 was the starting point for measuring the total impact of global warming. When and why did it shift to 1880 or, to use the nebulous GISS term, the “late 19th century”?

It will probably not surprise you that it happened during the Trump years, in late 2017. The more interesting question is how this shift was justified, given that everyone involved understood that it would result in a lower number for the total amount of global warming that has occurred.

In the next piece I examine the politics of how 1.2C was agreed upon as the amount of warming since “the late 19th century”. Here’s a clue, it depends on how you interpret the meaning of the word “preindustrial”.

There’s no science involved but a LOT of politics.

This is what I see.

This is my analysis.

This is my “Crisis Report”.

-rc