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Discovery of Carbon Dioxide and the Greenhouse Effect

Geologist, Alasdair Skelton explains how carbon dioxide was discovered and how this discovery led to the quantification of the greenhouse effect.
Joseph Black was a chemist working in Edinburgh during the Enlightenment. In a paper entitled Experiments upon Magnesia, Alba, Quick Lime and Other Alkaline Substances, which was first published in 1755, Joseph Black describes an experiment he did and conducted on Magnesia Alba. Now, Magnesia Alba is actually what we today called magnesium carbonate, and that’s actually what was used then and today to treat indigestion.
Joseph Black writes as follows: “Three ounces of magnesium alba were distilled in a glass retort and receiver, the fire being gradually increased until the magnesia alba was obscurely red hot. When all was cool, the magnesia alba, when taken out of the retort, had lost more than half of its weight.”
He goes on: “The volatile matter lost is mostly fixed air.” So what is fixed there? Let’s go and find out.
So my colleague, Lars is going to reenact Joseph Black’s experiment. Hi, Alasdair. Hi, Lars. So, some magnesium carbonate. Excellent. So magnesium carbonate is the same as magnesium alba. And we have a balance, a crucible and a furnace. So, we weigh the crucible with magnesium carbonate and put it in the furnace. Great. We heat it and it will decompose. And then we weigh it afterwards. Perfect. Excellent. Great. So, we’ll put it in the oven. Yeah. Then we should put this sample in- -the furnace, which is presently set at 665 degrees.
That’s warm. Yes. It could be a much warmer, but still. That’s it.
So now the sample will decompose, hopefully. And we have to leave it for about an hour. Something like that. OK, so we’ll come back in an hour. Yep. Thank you very much Lars. Thank you.
So we’ve been away for one hour now, and we’ve come back to the oven and we’re going to see what’s happened to the magnesium carbonate. It’s been, as I said, in the oven for one hour at a fairly high temperature, 818- -it says now. That is hot. That’s OK.
So, now into the balance.
And the crucible with contents now weighs 18.80-
-yeah, 18 point 80 grams. So nearly half of it - It started- -at 18.17. I filled it up with carbonate to 19.81, and now it’s down to, well half. It’s lost like almost a gram. Yes. So we put in roughly two grams and now there’s just about a gram left. Yeah. So, Joseph Black, when he had done this experiment, he analyzed the gas that was released and discovered that it was indeed what he called fixed air and what we now call carbon dioxide the greenhouse gas that ultimately causes global warming.
Thank you very much Lars. Thank you.
72 years later, in 1827, another scientist Fourier recognized that sunlight carries heat, that the atmosphere lets sunlight in, that the sunlight is converted to infrared at the Earth’s surface and that the atmosphere traps the infrared that would otherwise carry the heat back into space.
After another 34 years- -now we’re in 1861, Tynedale found out that it was carbon dioxide and water vapor in the atmosphere that trapped the heat.
It was 141 years after carbon dioxide was first discovered by Joseph Black that here in Sweden in 1896, the chemist Svante Arrhenius quantified the effect, and this effect is called the greenhouse effect. Arrhenius also hypothesized that by burning fossil fuels like coal, we would increase the carbon dioxide content of the atmosphere, and that would increase its ability to trap heat.
He gave the first indication of what we now call global warming.

Joseph Black was a chemist working in Edinburgh during the Enlightenment. In a paper which was first published in 1755, Joseph Black describes an experiment he did on a substance called magnesium alba. He heated this substance and found that it lost more than half of its weight. He called the matter that was lost fixed air. Today, we would have called it carbon dioxide.

In this video, geologist, Alasdair Skelton and chemist, Lars Eriksson, reenact this experiment in a laboratory in Stockholm. They confirm that magnesium alba, on heating, loses half of its mass. This was how carbon dioxide was first discovered.

In 1827, Fourier recognizing that the atmosphere traps heat from the Sun, and in 1861, Tyndall found out that it was carbon dioxide and water vapor in the atmosphere that trapped the heat. Today, we call this the greenhouse effect. This effect was quantified in 1896 by Svante Arrhenius. He also indicated that by burning fossil fuels, we would increase the carbon dioxide content of the atmosphere and thereby make the Earth warmer.

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