In 2006, Al Gore presented some information in his documentary, An Inconvenient Truth. (link to a 6 minute clip)
He presented the following chart:
This information is ACCURATE, but not complete.
Most critical thinkers will have a question come to mind, what would happen if there was NOT any human caused CO2 emissions?
Most critical thinkers would then speculate that the last cycle of the graph would repeat.
Most critical thinkers would then have some more questions.
Was another ice age about to start?
Did our CO2 emissions bump the earth OUT of a cycle?
Did we avoid another ice age?
Those were my thoughts in 2006, and as far as I can tell, they were correct, but for some reason, this information is usually left out of the discussions.
Al Gore also didn’t tell us anything about the CO2 levels prior to the start of his chart.
The chart below shows the CO2 levels throughout the entire history of the earth.
Most critical thinkers will wonder where Al Gore’s graph fits into the one above.
The first vertical line on the right, the one passing through QUATERNARY, represents the start of the Quaternary period, which was 2.58 million years ago. Al Gore’s graph showed only 800 thousand years, so his graph covered about one third of this. About the width of the white dot on the far lower right of this graph.
Visually, if we changed Al Gore’s graph to the same scales as the 600 million years graph, this is where it would fit:
The earth was a very different place 530 million years ago, when CO2 levels peaked near 8,000ppm, so complacently thinking that we have lots of margin is probably NOT a good idea.
Critical thinkers will wonder how the CO2 concentration increases in the atmosphere compare with the human emissions. The graph below shows that for the past 268 years.
Critical thinkers will notice that the two lines use different units of measure and different scales for the Y axis, and they will wonder what the graphs would look like if they have the SAME scales. Below is a replication of the graph that I created in Excel.
At first, I didn’t realize that I needed to plot the CUMULATIVE emissions, which is the grey line. In order to do that I had to enter data for every year, which was a little tedious and time consuming, so I only did back to 1960, but that was enough to show that the increased concentrations in the atmosphere DO correlate with the human emissions.
So, to summarize, it looks like the increased levels of CO2 in the atmosphere ARE primarily due to human emissions, but there’s a silver lining in that we will avert an ice age. Also, while the CO2 levels are higher than they would otherwise be, they are much lower than they’ve been at other times.
Why there has been such a furor about this for so many years is beyond me.
It seems to me that we need calm down and have honest discussions. We need to estimate what a reasonable level is and then be able to adjust it, up or down. Increased CO2 keeps an ice age away, and it allows us to grow more food for an increasing population. (CO2 is often pumped into greenhouses to increase plant growth.) Letting it get too high, might create some problems.