The logarithmic nature of the CO2 greenhouse effect

10/13/2019 09:00 - Posted by Tom van Leeuwen
For many people, a logarithmic relationship can be a fairly abstract concept. It is hard to imagine the implication that it has on the strength of the greenhouse effect that corresponds to the amount of CO2 that humanity emits into the atmosphere. Here we present a visualization to explain in a simple way what we are talking about.

CO2 is a greenhouse gas. The presence of CO2 in the atmosphere traps a part of the infrared radiation that the Earth's surface emits into space. The total greenhouse effect of the Earth's atmosphere is about 30 °C, without this effect, the temperature would be -15 °C instead of +15 °C, the actual current average temperature.
Water vapor is the most important greenhouse gas. CO2 provides 3 °C of heating, that is, 10% of the total effect.

When the concentration of CO2 increases, its greenhouse effect also increases, but not in a linear fashion, but logarithmically. For each increase in concentration, the effect on temperature is less and less.

In the main graphic of this article, generated using the radiation detection system of the United States Air Force (MODTRAN), the blue line represents the greenhouse effect of CO2. On the horizontal axis, we place the CO2 concentration and on the vertical axis the amount of energy the Earth receives per square meter of surface every second. The red lines mark the values of the beginning of the Industrial Revolution, the green lines the values for the year 2006 and the black lines the values that correspond to the doubled concentration we had at the beginning of the Industrial Revolution.
We observe that the CO2 greenhouse effect dramatically increases when the levels are low, while the increase in the effect is much lower with the current CO2 concentrations.

Given that the greenhouse effect of CO2 is only 10% of the total effect, it is clear that increasing the already existing concentration of CO2 in the atmosphere no longer has any measurable effect on the earth's temperature. This graphic is also from the US Army.

This phenomenon is known as the saturation of the CO2 greenhouse effect.

An approach to better understand the logarithmic progression of the effect:

We see that a tiny concentration of only 20 parts per million (ppm) is already sufficient to activate more than a third of the CO2 greenhouse effect. Increasing the concentration with 20 ppm to 40 ppm, the effect already produces 1.5 °C of heating, that's half of the total.
140 parts of CO2 per million is the minimum concentration necessary to sustain plant life. At this level, the greenhouse effect is completed by 67%. At the end of the last glacial period, 16 thousand years ago, the CO2 concentration was 180 ppm and its greenhouse effect was already 72% saturated.
At the beginning of the Industrial Revolution (1850), the saturation of the CO2 greenhouse effect reached 80%, 2.4 °C of the possible 3 °C. This means that CO2 emissions by humans never had any measurable effect on global temperature. For example: moving from the current 420 ppm CO2 to 440 ppm would cause heating of 0.02 °C.

With this knowledge it is clear why IPCC climate models do not work.
The models exaggerate the CO2 greenhouse forcing. They are programmed like this. From there, all positive feedback effects, such as the increase in the greenhouse effect of water vapor, fail.
The result is that the models forecast too much warming for the future.

If we could only get these images and this message to the responsible politicians, they would easily see that there is no rational reason to try to limit CO2 emissions.

Article based on this article from , the most visited climate website. I have corrected the heating °C of the third graph with the values calculated from the first graph. The heating of the first section is less than the 1.7 ° C value shown in the original graph. The other values have been changed accordingly.

Tom van Leeuwen, September 2019.


Please donate

Fighting the climate hysteria is time-consuming! If you think I'm on the right track and you want to support my efforts I would be more than happy to receive a small donation that will help me to maintain this site.


The fingerprints of the greenhouse effect

The hypothesis of "man-made climate change" tells us that the increase in the concentration of CO2 enhances the greenhouse effect of the atmosphere and has global warming as a final result.

Since the beginning of the industrialized era around 1850, man emits relatively large amounts of CO2 into the atmosphere through the use of fossil fuels. The consequence of these emissions is that during that period, the concentration of CO2 in the atmosphere increased sharply from about 300 parts per million to more than 400 ppm, an increase of almost 40%. The average temperature increased in the same period more or less 1.5 °C with a small variation depending on the data source used.

Why did the warming stop?

The political reports of the IPCC are based on the hypothesis that CO2 is the most important control knob of the Earth's temperature. The problem is that this hypothesis does not correspond at all with the empirical data available to science. Forecasts are made using models that are not capable of 'predicting' the past.

Temperature versus CO2 – the big picture

When discussing “Climate Change” it’s good to have an understanding of how the Earth’s climate has changed in the past. That will give us a reference to decide whether the current changes are normal or not.

Global temperatures have varied a lot over the last 500 million years. Depending on the timescale used, the current temperature is either cold or hot, so when you want to know the “normal temperature” you’ll have to indicate what timescale you’re using.

An estimation of the human influence on the climate

The month of May has come to an end. Another month of economic paralysis and reduced human CO2 emissions. And again, the CO2 concentration in the atmosphere continues to rise to record levels in modern measurements.

It is time to remove the blindfolds and thoroughly analyze the question of the effect of human CO2 emissions on global temperature. I propose to divide the problem into four issues, open for discussion:

Sydney Sea-Level Rise

According to the IPCC CO2-hypothesis, rising CO2-levels leads to warming. That warming supposedly expands sea-water and melts glaciers and polar ice-caps, finally resulting in rising sea-levels. They warn us for catastrophic sea-level rises in the year 2100 and beyond because of this process.

Sydney is strategically located between the Indian, Pacific, and Southern oceans. CO2-levels went up from 300 to 400 parts per million over the past 100 years. What's the impact on Sydney's sea-level?

Democracy? Make your choice!

In recent centuries the power of governments has become stronger and stronger. The governments got involved increasingly deeper into our lives and the citizens, the individuals, have ever less to say about ever more issues.

Climate policy is an excellent example of this interference. The government relies on completely unreliable data, unproven hypotheses, and ideas while the consequences of this interference affect everyone. At present, governments worldwide are about to make cheap and reliable energy sources -that form the basis of our economic prosperity- inaccessible. The results are far-reaching.

Censored and kicked by a Facebook group!

Yesterday I decided to post my Four Interglacials to a Facebook group called "Global Warming Denialism is a Big Oil agenda".

It was an educational experience.

About consensus, "97%", and settled science

There are four misconceptions about science that are commonly used by catastrophic man-made warming advocates. Normally, when you try to start a conversation on the subject, their first reply will be one of these four "arguments".