I just read an article in Slate, the online magazine, which disproved an item I had assumed, largely based on intuition, was true. I had always thought that the amount of carbon dioxide we humans exhale daily was something not accounted for in the calculations modelers make in projecting the effects of climate change. Otherwise how could human population growth not be mentioned as one of the major forcing factors on climate change?
The article told me that every ounce of carbon dioxide we exhale is balanced by the amount of carbon dioxide taken up by the plants required to sustain us via food we eat to stay alive.This would apply throughout the animal kingdom, so an unexpected expansion in any species’ population would not be the source of climate change.
This violated one of my baseline Assumptions: that human growth in population was the chief cause of the phenomenon of climate change.
I hate it when my baseline assumptions are challenged. So my mind went to work trying to find fault in the Slate article. To no avail. Where else were we getting the energy to produce the CO2 if not from the plants (animal protein comes from the plants it eats as well, so we might just as well ignore non-vegetarians in the analysis)?
But I still could not shake the firm intuitive conviction that human population growth was at the heart of the problem. I have long believed this to be true, and have almost as long wondered why the human population explosion has not been the center of the sustainability debate. Instead, it seems to be almost a forbidden topic.
The Slate article did contain some hope for my biases, though. It mentioned that fossil fuels, when converted directly to CO2, were taking long-term sequestered CO2 and converting it to atmospheric CO2, which is not balanced in the same sense that animal respiration and plant growth are.
So the Industrial revolution may be the culprit, and human population growth only secondarily to blame, since the former can only happen after the latter. (For a clarification of this point, read the excellent novel by George Stewart, Earth Abides.)
The pertinent statistic is not “How much CO2 do we each exhale?” but “How much CO2 do we each use?” The latter includes the amount required to move ourselves and the products we require in our lives about. Figuring it that way we can see how human population may still be at the root of the problem. I like that.
Now the question remains, “What are we going to do about it?”