Chapter 8: In Terms of CO2, We Are Returning to the Carboniferous Period

Since 1750, we have increased carbon in the atmosphere by around 50%. We measure atmospheric CO₂ in parts per million (ppm). Using core samples of ice and trees, we can accurately measure historical levels of CO₂ in the atmosphere. From these data, we know that 250 years ago the amount of CO₂ in the atmosphere was around 280 ppm.

When Charles David Keeling first started measuring atmospheric CO₂ levels at the Mauna Loa Volcano back in the 1950s, the atmospheric CO₂ was at 313 ppm, around 13% higher than it had been in the mid-1700s. Seventy years later, we are already at 417 ppm. This is the highest it has been in at least 14 million years. To make matters worse, this number is likely going to rise at an accelerating rate since oceans have been absorbing tremendous amounts of CO₂ from the atmosphere. At some point they will reach their limit.

It is no coincidence that this dramatic rise has occurred during the period in which we have cut down half of forests and grasslands, turned half of soil back to dirt, and killed life in droves. Recall that photosynthesis is the pump driving the movement of carbon from the atmosphere to a sequestered state within plants, soil, and other life. The pump grows stronger with more native plants, soil, and fresh water. The amount of sequestered carbon increases with growing populations and diversity of life. Yet we are damaging all parts of this system.

In addition, we are also pumping carbon into the atmosphere as we burn a tremendous amount of coal, oil, and natural gas to produce electricity. We learned in Chapter 4 that most of these fossil fuels were formed by plants during the Carboniferous Period. By mining and burning fossil fuels at an increasing rate, we release the carbon captured during that period and undo millions of years of photosynthesis.

Given that we are damaging the natural systems responsible for sequestering carbon while simultaneously emitting record levels of carbon previously captured by these same natural systems across millions of years, it should come as no surprise that CO₂ levels in the atmosphere are skyrocketing. Many scientists think we will hit 500 ppm within the next 30 years. Perhaps we will even hit 1,500 ppm at some point, which was the norm during the Carboniferous Period. Whatever happens, we know temperatures will get hotter due to basic climate science (see the sidebar).

But that is only the start. I’m more worried about the many things we cannot even begin to predict. How will unforeseen changes affect human economies, societies, and institutions? How might they derail the progress of life on Earth—or worse? Nassim Taleb wrote the following in Black Swan: “The position I suggest should be based both on ignorance and on deference to the wisdom of Mother Nature, since it is older than us, hence wiser than us, and has been proven much smarter than scientists. We do not understand enough about Mother Nature to mess with her.” I could not agree more.