You would think that the news of May 9 that, for the first time in human history, climate warming greenhouse gas had reached 400 parts per million (ppm), would command much greater attention than being relegated to the Environment section of The New York Times, and the back page of the weekend edition of the Brattleboro Reformer.
While admittedly symbolic, and only minutely worse than we were at 399 ppm the day before, it's nevertheless a number that should give us pause.
As The Guardian pointed out, “The last time so much greenhouse gas was in the air was several million years ago, when the Arctic was ice-free, savannah spread across the Sahara desert and sea level was up to 40 meters higher than today.”
During the 8,000 years of human civilization, carbon dioxide levels were generally stable at 280 ppm. But with the Industrial Revolution and the burning of fossil fuels, there has been a 42-percent increase.