Friday, December 20, 2013

THE END OF THE HUMAN RACE?

FROM TRUTHDIG


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Are We Falling Off the Climate Precipice?

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Posted on Dec 19, 2013
natura_pagana (CC BY 2.0)
By Dahr Jamail, TomDispatch
This piece first appeared atTomDispatch. Read Tom Engelhardt’s introduction here.
I grew up planning for my future, wondering which college I would attend, what to study, and later on, where to work, which articles to write, what my next book might be, how to pay a mortgage, and which mountaineering trip I might like to take next.
Now, I wonder about the future of our planet. During a recent visit with my eight-year-old niece and 10- and 12-year-old nephews, I stopped myself from asking them what they wanted to do when they grew up, or any of the future-oriented questions I used to ask myself. I did so because the reality of their generation may be that questions like where they will work could be replaced by: Where will they get their fresh water?  What food will be available? And what parts of their country and the rest of the world will still be habitable?
The reason, of course, is climate change—and just how bad it might be came home to me in the summer of 2010.  I was climbing Mount Rainier in Washington State, taking the same route I had used in a 1994 ascent.  Instead of experiencing the metal tips of the crampons attached to my boots crunching into the ice of a glacier, I was aware that, at high altitudes, they were still scraping against exposed volcanic rock. In the pre-dawn night, sparks shot from my steps.
The route had changed dramatically enough to stun me. I paused at one point to glance down the steep cliffs at a glacier bathed in soft moonlight 100 meters below. It took my breath away when I realized that I was looking at what was left of the enormous glacier I’d climbed in 1994, the one that—right at this spot—had left those crampons crunching on ice. I stopped in my tracks, breathing the rarefied air of such altitudes, my mind working hard to grasp the climate-change-induced drama that had unfolded since I was last at that spot.
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I haven’t returned to Mount Rainier to see just how much further that glacier has receded in the last few years, but recently I went on a search to find out just how bad it might turn out to be. I discovered a set of perfectly serious scientists—not the majority of all climate scientists by any means, but thoughtful outliers—who suggest that it isn’t just really, really bad; it’s catastrophic.  Some of them even think that, if the record ongoing releases of carbon dioxide into the atmosphere, thanks to the burning of fossil fuels, are aided and abetted by massive releases of methane, an even more powerful greenhouse gas, life as we humans have known it might be at an end on this planet. They fear that we may be at—and over—a climate change precipice hair-raisingly quickly.
Mind you, the more conservative climate science types, represented by the prestigious Intergovernmental Panel on Climate Change (IPCC), paint scenarios that are only modestly less hair-raising, but let’s spend a little time, as I’ve done, with what might be called scientists at the edge and hear just what they have to say. 
“We’ve Never Been Here as a Species”
“We as a species have never experienced 400 parts per million of carbon dioxide in the atmosphere,” Guy McPherson, professor emeritus of evolutionary biology, natural resources, and ecology at the University of Arizona and a climate change expert of 25 years, told me. “We’ve never been on a planet with no Arctic ice, and we will hit the average of 400 ppm… within the next couple of years. At that time, we’ll also see the loss of Arctic ice in the summers… This planet has not experienced an ice-free Arctic for at least the last three million years.”
For the uninitiated, in the simplest terms, here’s what an ice-free Arctic would mean when it comes to heating the planet: minus the reflective ice cover on Arctic waters, solar radiation would be absorbed, not reflected, by the Arctic Ocean.  That would heat those waters, and hence the planet, further. This effect has the potential to change global weather patterns, vary the flow of winds, and even someday possibly alter the position of the jet stream. Polar jet streams are fast flowing rivers of wind positioned high in the Earth’s atmosphere that push cold and warm air masses around, playing a critical role in determining the weather of our planet.
McPherson, who maintains the blog Nature Bats Last, added, “We’ve never been here as a species and the implications are truly dire and profound for our species and the rest of the living planet.”
While his perspective is more extreme than that of the mainstream scientific community, which sees true disaster many decades into our future, he’s far from the only scientist expressing such concerns. Professor Peter Wadhams, a leading Arctic expert at Cambridge University, has been measuring Arctic ice for 40 years, and his findings underscore McPherson’s fears.  “The fall-off in ice volume is so fast it is going to bring us to zero very quickly,” Wadhams told a reporter. According to current data, he estimates “with 95% confidence” that the Arctic will have completely ice-free summers by 2018.  (U.S. Navy researchers have predicted an ice-free Arctic even earlier—by 2016.)
British scientist John Nissen, chairman of the Arctic Methane Emergency Group (of which Wadhams is a member), suggests that if the summer sea ice loss passes “the point of no return,” and “catastrophic Arctic methane feedbacks” kick in, we’ll be in an “instant planetary emergency.”
McPherson, Wadham, and Nissen represent just the tip of a melting iceberg of scientists who are now warning us about looming disaster, especially involving Arctic methane releases. In the atmosphere, methane is a greenhouse gas that, on a relatively short-term time scale, is far more destructive than carbon dioxide (CO2).  It is 23 times as powerful as CO2 per molecule on a 100-year timescale, 105 times more potent when it comes to heating the planet on a 20-year timescale—and the Arctic permafrost, onshore and off, is packed with the stuff.  “The seabed,” says Wadham, “is offshore permafrost, but is now warming and melting. We are now seeing great plumes of methane bubbling up in the Siberian Sea… millions of square miles where methane cover is being released.”
According to a study just published in Nature Geoscience, twice as much methane as previously thought is being released from the East Siberian Arctic Shelf, a two million square kilometer area off the coast of Northern Siberia. Its researchers found that at least 17 teragrams (one million tons) of methane are being released into the atmosphere each year, whereas a 2010 study had found only seven teragrams heading into the atmosphere.
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