Keeling Over: Carbon Dioxide Levels Higher Than At Any Time In Human Evolution

Keeling CurveEvery day, millions of tons of carbon dioxide are spewed into our planet’s atmosphere as a result of extracting and consuming fossil fuels. According to the GAO, global CO2 emissions have increased over 2.5 percent a year over the last century. Decades ago, Charles Keeling noted that CO2 levels were increasing steadily over time, along with emissions and global temperatures. Thus was born the “Keeling Curve”, a widely used measure of atmospheric CO2. Now, Keeling’s curve is about to breech a new record. For the first time in human history, the concentration of CO2 in the atmosphere will reach 400 parts per million. Keeling’s son Ralph, a researcher at Scripps Institute of Oceanography, says “There’s no stopping CO2 from reaching 400 ppm. That’s now a done deal.”

Two hundred, four hundred, a thousand parts per million. What does that number mean, exactly? According to NOAA , before the Industrial Revolution, global average CO2 was about 280 ppm. During the last 800,000 years, CO2  fluctuated between 180 ppm during ice ages and 280 ppm during warmer periods. Today’s rate of increase is more than 100 times faster than the increase that occurred when the last ice age ended.

Andrew Freeman, writing at Climate Central, puts the new CO2 figure in terrifying context: These carbon dioxide levels haven’t been seen on planet earth during the whole of human evolution. In case that 800,000 year figure cited by NOAA doesn’t grab your attention, Freeman points to research indicating such levels haven’t been seen in 15 million years.

‘The last time there was this much carbon dioxide in the Earth’s atmosphere, modern humans didn’t exist,” writes Freeman. “Megatoothed sharks prowled the oceans, the world’s seas were up to 100 feet higher than they are today, and the global average surface temperature was up to 11°F warmer than it is now.”

The notion that human evolution has brought our species to the point where we can alter the basic planetary conditions which allowed us to thrive in the first place is sobering, to say the least. Given that the Keeling curve’s trajectory is likely take us beyond 450 ppm or higher, bending that curve down should be a global priority. There’s no guarantee we could survive a precipitous plunge back into a climate like that which prevailed fifteen million years ago.

One response to this post.

  1. […] recently wrote about how the concentration of CO2  in the environment has reached a point higher than it has been […]


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