Humanity on Friday passed a milestone on the way to planetary destruction when monitoring stations registered 400 parts per million of carbon dioxide spread throughout the atmosphere.
“The last time so much greenhouse gas was in the air,” The Guardian reports, “was several million years ago, when the Arctic was ice-free, savannah spread across the Sahara desert and sea level was up to 40 metres higher than today.” Those conditions are expected to return if governments and global businesses do not severely and rapidly curtail the amount of CO2 being dumped into the atmosphere by the burning of coal, oil and gas.
“It is symbolic, a point to pause and think about where we have been and where we are going,” said professor Ralph Keeling, who oversees the measurements on a Hawaiian volcano. “It’s like turning 50: it’s a wake up to what has been building up in front of us all along.”
Professor Rajendra Pachauri, chair of the Intergovernmental Panel on Climate Change, said: “The passing of this milestone is a significant reminder of the rapid rate at which—and the extent to which—we have increased the concentration of greenhouse gases in the atmosphere. ... At the beginning of industrialisation the concentration of CO2 was just 280ppm. We must hope that the world crossing this milestone will bring about awareness of the scientific reality of climate change and how human society should deal with the challenge.”
The world’s governments have agreed to keep the rise in global average temperature, which have already risen by over 1C, to 2C, the level beyond which catastrophic warming is thought to become unstoppable. But the International Energy Agency warned in 2012 that on current emissions trends the world will see 6C of warming, a level scientists warn would lead to chaos. With no slowing of emissions seen to date, there is already mounting pressure on the UN summit in Paris in 2015, which is the deadline set to settle a binding international treaty to curb emissions.