Global Warming VII – Carbon Dioxide History


Continuing my series of posts (see Global Warming I, Global Warming II, Global Warming III, and Global Warming IV, Global Warming V, Global Warming VI) about Global Warming I have graphs of carbon dioxide in the atmosphere from the Scripps Institution of Oceanography. I think that these are significant for several reasons and in several contexts.

First, these data support my contention that no citizen should vote for any Republican for any office from school crossing guard and dog catcher and higher. That party must be delivered an unmistakable message from voters that it cannot invent its own reality, and it must stop damaging the world.

Second, these data show powerful evidence, through correlation, if nothing else, that human activity has led to a major and still unending increase in CO2 in the atmosphere. As the knowledge that tells us that water vapor and carbon dioxide and some other gases are major factors determining Earth’s climate and temperature goes back more than 100 years and is not in question even by global warming deniers, those deniers have the serious problem of demonstrating why the major increase in atmospheric CO2 has not caused the observed surface temperature increase of recent decades.

Third, these data show that, as many of those who deny the importance of global warming assert, the climate has always changed and will continue to do so. But those who deny the importance of global warming with this true claim, many politicians among them, neglect to mention that the change in CO2 concentrations that we are experiencing is unprecedented in the past million years, at least, and that it extends far beyond the range of any earlier fluctuations.

Fourth, those who assert that humanity should and can merely adapt to these changes, an adaptation that they claim will not be difficult, neglect to mention that the entire span of human civilized existence, about 10,000 years, has also been a span of stable CO2 and stable climate. Thus, we have no certain ideas as to what will happen to the climate in the future nor any way to predict whether civilization will be able to maintain itself. Although this will not make much difference to me, now that I am an old guy, I am an alarmist because I believe alarm is justified.

Fifth, I apologize to coming generations for the mess my generation and a few earlier ones are leaving for them. We have much to be proud of, but global warming is a horrid blot upon our reputations.

Here’s the justly famous Keeling curve:

Dr. Charles Keeling, as you can see, began hiking to the top of Mauna Loa volcano in 1958. The project continues under the direction of his son, Dr. Ralph Keeling. Those little wiggles are seasonal variations. When the data record begins the CO2 concentration was about 315 ppm, about 0.03%. Now it is a bit over 400 ppm. The trend is upward, and there is no suggestion that it may decline in the future. Dr. Keeling the younger believes that we have entered an era in which CO2 concentration will not go below 400 ppm again, unless something drastic happens.

Here’s the data going back to 1650, nearly 400 years. These data combine the Keeling curve with ice core records.

In this record, I think you can see the long term, pre-industrial age average, a bit below 280 ppm. The industrial age, burning coal appears weakly at first, and then with increasing clarity after about 1800. The rapid transformation of the lives of billions of people, in India and China, during the past few decades has been, and continues to be, the greatest enhancement in human welfare in human existence. This transformation of these immense populations to a modern advanced life is a great boon to them and to us, but it has come with greatly increase production of CO2.

Here’s the record going back 10,000 years. I take 10,000 years, to 8000 BCE, to be the span of civilized, settled human existence, and the beginning of agriculture.

Perhaps someone might see a trend in this over thousands of years, but I’d just say that CO2 concentrations have been stable around 270 ppm or so throughout this span, except for the last 150 years. This last 150 years shows an astonishing departure. In my opinion, this graph puts the lie to the pronouncements of those who believe that there is little for us to concern ourselves with in the “speculations” of ivory tower researchers. This is not within the error bars or typical fluctuations.

Here’s the record going back 800,000 years, again from ice core records with the Keeling curve calibrated and placed at the end.

In this record, you can see the coming and going of ice ages. The glaciers covered most of North America, Europe, and northern Asia, a mile thick, when CO2 levels were low, and receded when they were high. These fluctuations in CO2, and in the climate, were driven by entirely natural causes, and they are the subject of discussion among researchers. Solar cycles, volcanoes, changes in ocean circulation, are among the proposed causes. The spike at the far right of the curve, however, far beyond and faster than any of the fluctuations on this graph. (Indeed, the zero level, not shown on the graph whose y-axis begins at 150 ppm, is as far below as the spike is above its starting point.) There is no suggestion that the spike has settled down into the wiggles during war spells or cold spells. Remember that modern humans walked out of East Africa to populate the world about 60,000 years ago. It was during an ice age. Sea levels were much lower than today, so those early wanderers followed the sea shore, now underwater, all the way to Australia. Our species appears in the fossil record about 200,000 ago. No doubt the fluctuations in the climate of East Africa, over the past million years had a significant role in our evolution.

Here’s an xcdc comic that makes this same point. He goes back 20,000 years, and it is worth taking a look.


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Filed under Climate Change, Environment, Natural Science, Physics

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