[Coral-List] CO2 hits 400ppm

BRUCE CARLSON exallias2 at gmail.com
Thu May 9 22:00:13 EDT 2013

Probably everyone (in the U.S.) has heard the news that the Dow Jones average has surpassed 15,000 and everyone is jubilant.  

You may have missed another story that appeared at almost the same time.  Here is an excerpt of that story from The Economist:  

 "At NOON on May 4th the carbon-dioxide concentration in the atmosphere around the Mauna Loa Observatory in Hawaii hit 400 parts per million (ppm). The average for the day was 399.73 and researchers at the observatory expect this figure, too, to exceed 400 in the next few days. The last time such values prevailed on Earth was in the Pliocene epoch, 4m years ago, when jungles covered northern Canada.  There have already been a few readings above 400ppm elsewhere—those taken over the Arctic Ocean in May 2012, for example—but they were exceptional. Mauna Loa is the benchmark for CO2 measurement ... because Hawaii is so far from large concentrations of humanity."

We all know the predictions for climate change and ocean chemistry change as we now head, inevitably it appears, to 450ppm.

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