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Sat May 4, 2013, 06:59 PM

Yay, Humans! We're the Best: Earth's carbon dioxide levels to hit 400 ppm

Global carbon dioxide levels will likely reach 400 parts per million within days, scientists report, an ominous milestone that's unprecedented in human history. Earth's atmosphere hasn't contained that much CO2 since the Pliocene Epoch, an ancient era that ended more than 2 million years before the first Homo sapiens appeared.

This forecast is based on data from the Mauna Loa Observatory (MLO) in Hawaii, considered the gold standard in CO2 measurements due to its deep data record and isolation from major pollution sources. Located on a 13,000-foot-tall mountain in the Pacific Ocean, the monitoring station recorded a daily average of 399.5 ppm on April 29, and some hourly readings have already surpassed 400 ppm. CO2 levels fluctuate seasonally during the year, and typically peak at Mauna Loa in mid-May.

Although 400 ppm isn't a so-called "tipping point" for climate change, it is a symbolic threshold that illustrates how dramatically humans have altered the atmosphere in just a few generations. Global CO2 levels had hovered between 170 ppm and 300 ppm for thousands of centuries until the Industrial Revolution, then suddenly began to skyrocket. They had reached 317 ppm by 1958, when climate scientist Charles David Keeling established the MLO, and were up to 360 ppm by the end of the 20th century.

"I wish it weren't true, but it looks like the world is going to blow through the 400-ppm level without losing a beat," says Ralph Keeling, a geochemist at the Scripps Institution of Oceanography who has continued the work of his father, the late Charles David Keeling. "At this pace we'll hit 450 ppm within a few decades."

The following two charts demonstrate the speed of this carbon bombardment. The first a Scripps-produced plot of MLO data dubbed the "Keeling curve" shows how atmospheric CO2 concentrations have risen by about 25 percent since the late 1950s:


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Reply Yay, Humans! We're the Best: Earth's carbon dioxide levels to hit 400 ppm (Original post)
MrScorpio May 2013 OP
aristocles May 2013 #1

Response to MrScorpio (Original post)

Sat May 4, 2013, 07:29 PM

1. It goes up, it goes down


If humans et al. die some other life form will evolve to replace us... Maybe carbon dioxide breathing cockroaches. In the grand scheme of things everything achieves equilibrium and then decays into nothingness.

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