Happy Earth Day. We Just Reached Another Scary Climate Change Milestone, is an excellent article by Kate Sheppard, on carbon Dioxide concentrations that have been measured above 400 parts per million at the Mauna Loa Observatory, in Hawaii for all of the last month.
The late renowned scientist, Charles David Keeling, , began keeping daily measurements of atmospheric carbon at Mauna Loa in 1958ma and his record is known as the "Keeling Curve.
"This is higher than it's been in millions of years," said Pieter Tans, a senior scientist with the National Oceanic and Atmospheric Administration's Climate Monitoring and Diagnostics Laboratory.
Parts per million, or ppm, is a measure of the ratio of carbon dioxide to other gases in the atmosphere. Carbon dioxide is just one type of greenhouse gas that has been found to trap heat, but it is the primary one emitted from human activities and it lingers in the atmosphere for a very long time. There is typically seasonal fluctuation in the parts per million (ppm) of carbon dioxide, according to scientists who track the levels. That explains why, after hitting 400 for the first time in recorded history last May, the levels declined soon after. But they hit 400 ppm again in mid-March, and have stayed above that level for all of April.
As of April 20, the level of carbon dioxide in the atmosphere was 401.17 ppm. That figure is based on readings from the Mauna Loa Observatory in Hawaii. The scientists who monitor atmospheric carbon dioxide levels expect that levels will stay above 400 ppm until late June or July.
Tans said that the level of CO2 in the atmosphere is now increasing at a rate that is at least 100 times faster than it has been at any time since record-keeping began. At some point next year or the year after, based on current rates, carbon dioxide levels will rise above 400 ppm and will not be likely to fall below that mark again.
400 ppm is seen as mostly a psychological level, that should be a "wake up call."
The article goes on to note that if we are going to keep CO2 levels below 500pm or the more desirable 450 ppm we are going to need significant reductions in the amounts of fossil fuels we are burning.
Kate Sheppard closes by quoting Bill McKibben, co-founder of 350.org, suggesting that the best way to interpret this number is like going to the doctor and learning you have a really high cholesterol level. Are you going to do something about it our not -- changing one's diet and exercisig. McKibben is critical of the U.S. government for not taking sufficient action in response to these warnings.