Module 2707



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The “enhanced greenhouse effect”

How much has the concentration of carbon dioxide in the atmosphere increased since the beginning of the Industrial Revolution?
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So what?
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In the beginning .....

It is 1800 (not quite the beginning). Carbon dioxide has been in our atmosphere forever. So too has been the greenhouse effect (Module 2705 The “greenhouse effect”).

For centuries the concentration of carbon dioxide in the atmosphere has been fairly consistent at about 275 ppm. At this level, the greenhouse effect controls the average temperature at the surface of Earth at about + 15 °C, which is 33 °C higher than if there were no carbon dioxide (Module 2704 Does carbon dioxide affect Earth’s energy balance?).

Carbon dioxide is good!
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The industrial era arrives .....

In return for the benefits that we have enjoyed from the industrial era, is there a payoff coming? During this period, the concentration of carbon dioxide in the atmosphere has increased dramatically – although it could still be considered low (42 carbon dioxide molecules in every 100 000 molecules in the air).
 

Carbon dioxide concentrations 1760 - 2020. Carbon dioxide concentrations have been measured directly at Mauna Loa, Hawaii, since 1958. Data before 1958 are derived from gases trapped in ice.

The mean concentration of carbon dioxide in the atmosphere has now reached 421 ppm – a massive 50% increase over the past couple of centuries.

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Just natural variation?
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Some people say, dismissively .....
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“The carbon dioxide concentration has been high before! No problem.”

They should stop trying to confuse the voters ....
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For the past 800 000 years, the carbon dioxide concentration has not exceeded 300 ppm – the same as it was in 1950. It is now 421 ppm. Graph courtesy of NASA.

There is no doubt. Ignore the discombobulators.


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A link: Carbon dioxide concentration and temperature
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Since carbon dioxide in the atmosphere is responsible for warming of the surface of Earth (the “greenhouse effect”) we should expect that increasing concentrations will lead to still higher temperatures.
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There is an evident link between the increasing concentration of carbon dioxide in the atmosphere and the higher global temperatures.

Since increasing concentrations of carbon dioxide are enhancing global temperatures, this phenomenon is called the “enhanced greenhouse effect”. This refers to the increase in global temperature due to increasing carbon dioxide concentration since the pre-industrial era.
 

There has always been the “greenhouse effect” – natural and beneficial to life – with carbon dioxide being the good guy. Now we are experiencing the “enhanced greenhouse effect” – leading to many potential problems facing the human race. Is our perception of carbon dioxide deservedly changing from “good” to “bad”.

Of course, these problems cannot be attributed to carbon dioxide. The fault lies with human beings. Us.
 

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Is the link scientifically proven?
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Some people say ....
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“Scientists can’t agree on Earth’s temperature changes, so it is all a fraud.”

Yeah well ….
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Here’s what “disagreement” looks like! The four sets of data are measurements, obtained by different methods, from four different high-level research institutions in various countries.

An analogy would be if two different international astronomers have simultaneously, but independently, identified a previously unknown exoplanet. One publishes an estimate that it is 195 742 light years from Earth, but the other has estimated that it is 195 751 light years away.

​Do we conclude that they don’t agree, so their findings are untrustworthy – so let’s not believe anything they say?
 
There is no doubt.
 

And just for interest .....
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You may have noticed the wavy values in the concentrations in the graph of increasing carbon dioxide concentrations since direct analyses have been carried out. Let’s have a closer look …..
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The concentration of carbon dioxide in the atmosphere has one maximum, and one minimum, each year.

Zooming in further, to the past few years .....
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The data points on the red line are month-by-month measurements. After a maximum each March-April, concentrations begin to decrease each May, bottoming out each November before increasing again. Hawaii is in the Northern hemisphere.

Can you explain that natural phenomenon?
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LEARNING CHEMISTRY FOR UNDERSTANDING

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