By David Levy.
A milestone on the road to catastrophic climate change was reached last Thursday, May 9th, when the Mauna Loa research center in Hawaii recorded atmospheric CO2 levels above 400 parts per million (ppm) for the first time. The level during pre-industrial times was around 280 ppm, and has been rising at an accelerating pace due to burning fossil fuels and clearing forests. For the last 400,000 years or so, CO2 levels have fluctuated between about 180 ppm, at the depths of ice ages, and 280 ppm during relatively short warm periods, or interglacials (see graphic). The last time CO2 levels reached 400 ppm was at least 3 million years ago, a much warmer world where sea levels were 60-80 feet higher. Continue reading