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Greenhouse Gas Levels Close To Topping 400 Parts Per Million

/ Post by Polar Bears International

*Photo copyright Craig Taylor

Up, up, and up. Scientists are closely monitoring the rapid rise of carbon dioxidein the atmosphere, which has climbed at an alarming pace to nearly 400 parts per million, according to readings from Mauna Loa, Hawaii.

That level has not been seen for 3.2 million to 5 million years, during the Pliocene, according to the Scripps Institution of Oceanography at the University of California, San Diego—and it has never climbed with such speed. During the Pliocene, the average temperature rose as much as 18 degrees Fahrenheit and sea levels ranged between 16 to 131 feet higher than they are today, said Richard Norris, a Scripps geologist, in an interview with the Los Angeles Times.

Scripps has released a daily Keeling curve update showing the upward climb of carbon dioxide levels from the late 1950s on. They predict that CO2 levels could top 400 parts per million later this month and could reach 450 within a few decades.

“The 400-ppm threshold is a sobering milestone, and should serve as a wake-up call for all of us to support clean-energy technology and reduce emissions of greenhouse gases, before it’s too late for our children and grandchildren,” said Tim Lueker, an oceanographer and carbon cycle researcher who is a longtime member of the Scripps CO2 Group.

Dr. Steven C. Amstrup, our chief scientist, agreed. “We’re reaching dangerous levels of greenhouse gas concentrations that are already affecting polar bear habitat,” he said. “Our research has confirmed that, other things being equal, polar bears are likely to persist in relevant numbers over significant portions of the Arctic if we can keep CO2 at or below 450 parts per million. But the relentless climb in CO2 means if we are to stay below that value, the time to act is now. If we don’t, we’ll no longer be worried about polar bears—but life as we know it on Earth.”