The Keeling curve of CO2

We have all heard by now that we've pushed atmospheric CO2 to dangerously high levels. You've seen the now-ico0nic graph of carbon dioxide ascending, oscillating through the season, but inexorably rising over the years. This, perhaps the most recognizable, frightening, and convincing diagram in all of earth science, is called the Keeling curve, after Charles David Keeling, who in 1958 somewhat quixotically began monitoring airborne carbon dioxide from Mauna Kea, in Hawaii. Over the intervening decades, up to his death in 2005, he staunchly maintained a continuous set of observations that allowed us to see what we are doing with stark clarity. After just a few years the emerging pattern in Keeling's curve was key to getting scientists to realize that human industrial intervention really was changing our atmosphere at an accelerating rate. Now it has become key for our efforts to communicate this reality to everyone else. Keeling's measurements started a year before I was born (in 1959) Since then, the amount oc CO2 has risen almost 30 percent. That's not a tweak; it's a jolt.

Our planet has not experienced four hundred parts per million of CO2 for almost two million years. The details of our ancestry are still being worked out, but it seems that the last time there was this much greenhouse warming, some of the first humans (that is, members of the genus Homo) had recently appeared on Earth. These Homo habilis were using early stone tools along the drying rivers and spreading savannahs of East Africa as the climate warmed. Anatomically modern Homo sapiens first appeared in East Africa around three hundred thousand years ago. Nobody from our species has ever breathed air as thick with CO2 as we do today. ~ Page 117 / 118