Last May, the world hit a major milestone when levels of atmospheric carbon dioxide surpassed 400 parts per million for the first time in what may have been 3 million years of Earth's history. It was a big deal, even though it was only temporary.
This year, we hit 400ppm in record time, crossing the symbolic barrier on March 12 -- a full two months earlier than the first time around. And as April came to a close, we had another record on our hands: CO2 levels not only surpassed 400ppm, they stayed there for the entire month.
A new video from the Cooperative Institute for Research in Environmental Sciences shows just how extreme and unprecedented the rise in human-emitted greenhouse gases has been, beginning with the Industrial Revolution and accelerating at a nearly unbelievable pace in recent decades.
And it helps to explain another key message: as was made clear Tuesday in a landmark U.S. report, climate change is happening now, and we're all already experiencing its impacts. Speaking with reporters, Dr. John P. Holdren, the president's chief science and technology advisor, called the information collected in the report the “loudest and clearest alarm bell to date” signaling the urgent need to take action.
“We know that the world is getting warmer on average because of our continued emissions of heat-trapping gases," James Butler, director of the Global Monitoring Division of NOAA’s Boulder-based Earth System Research Laboratory (ESRL), said of the rising CO2 levels. "Turning down the dial on this heating will become increasingly more difficult as concentrations of the long-lived greenhouse gases continue to rise each year.”
Check out the animation below: