Carbon dioxide levels dating far back
During the Jurassic Period, dinosaurs — ranging from the plant-eating Diplodocus and Brachiosaurus to the meat-craving Ceratosaurus and Megalosaurus — ruled the world.
During this time, the Earth's interior was not standing still; rather, the supercontinent Pangaea had started to split into two smaller landmasses, called Laurasia and Gondwana.
These tectonic movements made the oceans close up and the tectonic plates sink into the Earth.
This process, called subduction,led to volcanism at the surface, with rocks constantly melting and emitting CO2 into the atmosphere.
Neither the principal investigators nor CDIAC is responsible for misuse of these data. At the Bern laboratory, four to six samples of approximately 8 grams from each depth level (0.55m intervals) in the ice core are crushed under vacuum conditions.
The sample container is connected to a cold trap for several minutes to release air from the clathrates and the air is then expanded to a measuring cell where a laser measures absorption in a vibration–rotation transition line of the CO-in-air standard gas of 251.65 parts per million by volume (ppmv) scaled on the WMO mole fraction scale.
The Keeling Curve, the iconic graph that presents these data, is a powerful symbol of the human impact on the environment and the role of fossil fuels in global climate change.
Keeling says that by November this year, we could be pushing towards new highs, and perhaps even breaking the 410 ppm barrier.
"[I]t already seems safe to conclude that we won’t be seeing a monthly value below 400 ppm this year - or ever again for the indefinite future," he adds.
According to the latest figures, levels of atmospheric carbon have officially surpassed 400 parts per million (ppm), and there’s little hope of returning them to safe levels - the situation is now permanent. Well, the 'safe' level of CO2 in the atmosphere is considered to be 350 ppm, and the last time Earth experienced levels that were consistently this high was roughly 4 million years ago.
That means humans have literally never experienced CO2 like this before.