New study shows carbon dioxide's impact on global warming ended decades ago
The greenhouse party is over
If we had only understood better what a greenhouse is, maybe it wouldn’t have been so easy to con us all.
A new study published in Science Direct has told us what physicists should have been telling us all along: The warming effect of carbon dioxide in the atmosphere is naturally limited, and that limit has already been reached. Even if we dug up all the world’s coal and extracted all the world’s oil and burned it in one giant pyre, its CO2 emissions wouldn’t heat the planet.
Don't let NASA educate your kids
NASA, writing for kids, presents the greenhouse effect as simple cause-and-effect.
How are humans impacting the greenhouse effect?
Human activities are changing Earth's natural greenhouse effect. Burning fossil fuels like coal and oil puts more carbon dioxide into our atmosphere.
NASA has observed increases in the amount of carbon dioxide and some other greenhouse gases in our atmosphere. Too much of these greenhouse gases can cause Earth's atmosphere to trap more and more heat. This causes Earth to warm up.
What NASA doesn’t mention is that carbon dioxide doesn’t cause Earth to warm up infinitely.
What goes up might not continue going up forever
The three Polish scientists at the Military University of Technology in Warsaw who authored this latest study were following in the footsteps of other scientists who drew similar conclusions in their own research, published in the last few years (here, and here). Mainstream news sites have not reported on these studies.
Although the scientific language of these studies is difficult to follow for the average man-on-the-street, the underlying concept is not. Going back to the greenhouse, let’s imagine a hypothetical situation where someone very foolish has lit a fire inside the greenhouse which is steadily emitting heat. The greenhouse gets hotter, and hotter, and hotter... but at some point, the heat will start to dissipate and the temperature inside levels off. The glass walls and ceiling can contain only so much heat before they start emitting it to the outside.
The case of CO2 in the atmosphere is very similar. Yes, it can act as a “greenhouse” gas, but like our hypothetical greenhouse, all the CO2 together can only contain so much heat. CO2 Coalition explains that, "The warming effect of each molecule of CO2 declines as [CO2's overall] concentration increases." Once the overall limit has been reached, adding more CO2 has no more than minimal effect.
The greenhouse party may have ended before the first coal-fired factory was built
The Polish scientists assert, based on their findings, that there is “currently a multiple exceedance of the saturation mass for carbon dioxide in the Earth’s atmosphere.” That is to say, we already reached the point, long ago, where CO2 lost its effectiveness in warming the planet.
Scientists at McGill University made the same point last year:
Transmission in the CO2 band center is unchanged by increased CO2 as the absorption is already saturated.
By “already saturated,” they meant that absorption has been saturated for centuries—since the “pre-industrial age” in fact.
But CO2 must be the bogeyman, because… science!
The level of CO2 in the atmosphere is a little above 400 ppm today. According to Prof. Dieter Schildknecht of Bielefeld University, Germany, carbon dioxide’s saturation level is just 300 ppm, a level that was probably reached around 1950, as the graph below illustrates. Based on previous research, Schildknecht writes that beyond this level, emissions caused by human activity have no significant effect on carbon dioxide’s greenhouse properties.
According to National Geographic, however, CO2 levels reaching 400 ppm was a “climate milestone,” and they add that,
The last time the concentration of Earth's main greenhouse gas reached this mark, horses and camels lived in the high Arctic. Seas were at least 9.1 meters (30 feet higher)—at a level that today would inundate major cities around the world.
National Geographic doesn’t provide any evidence to prove these remarkable assertions, though it does admit that “the last time the concentration of CO2 was as high as 400 ppm was probably in the Pliocene Epoch...” (emphasis added). It then attempts to bolster the case by writing that,
But tens of millions of years ago, CO2 must have been much higher than it is now—there's no other way to explain how warm Earth was then.
Pseudo-scientific scaremongering
There are actually many ways, like changes in solar activity, to explain why Earth may have been warmer (as well as colder, at times) in the past.
But what National Geographic—and almost everyone else in the Blob—wants to you to take away is this, the fear of the future unknown:
The planet was about 2 to 3 degrees Celsius (3.6 to 5.4 degrees Fahrenheit) warmer. But Earth then was in the final stage of a prolonged greenhouse epoch, and CO2 concentrations were on their way down. However, the May 2013 reading represented something different. This time, 400 ppm was a milepost on a far more rapid uphill climb toward an uncertain climate future.
Parents may want to check how much of their children's science text books are filled with such fearmongering as opposed to proper physics, such as explanations of how greenhouses and greenhouse gases work.
