Reposted from James Wilt at Vice as excerpted on daily kos: "Of all the climate change issues that have been melodramatically dubbed a "carbon bomb" in recent years—tar sands projects in Alberta, catastrophic wildfires in Indonesia, holes in Australia's seagrass meadows—it seems the thawing of permafrost in the Arctic is most likely to live up to the hype. There's a staggering amount of methane and carbon dioxide, like hundreds of gigatons worth, trapped under the permanently frozen layer of soil and rock in the form of ice crystals and biomass. If released due to the ongoing crescendo of warming in the Arctic, it could trigger a global feedback loop and burn us all to a f*ing crisp. Yet there's another very real issue associated with thawing permafrost that's received far less attention outside of industry circles, perhaps because of the lack of a catchy apocalyptic phrase to accompany it. For decades, mine operators in Northern Canada have stored waste rock and tailings waste—the "pulverized rock slurry" byproduct of mineral processing that's filled with skeevy chemicals like arsenic, lead, and mercury—in frozen dams reinforced with permafrost, an option far cheaper than constructing artificial structures to house the goop. But if such walls thaw, allowing air and water to interact with the highly reactive tailings, widespread "acid mine drainage" (AMD) could occur. Such a process can generate sulphuric acid and result in the leaching of heavy metals into nearby soil and water sources. "Permafrost degradation is going to affect everything," says Magdalena Muir, research associate at the University of Calgary's Arctic Institute of North America. "When you have frozen infrastructure, you don't have to build an artificial structure and probably get used to not having to worry too much about breaches. But as soon as you have soil that behaves just like any other soil, you have all the issues you'd have in southern Canada." The Canadian mining sector produces around one million tons of waste rock and 950,000 tons of tailings per day. As a result, the prospect of widespread AMD could be disastrous for the Canadian North: such scenarios would obviously be nightmares to contain, with the remoteness and cold climate seriously impeding cleanup. Think the Deepwater Horizon of the Arctic, except not nearly as visible and minus the dead dolphins to draw attention to the disaster. And like methane bubbling out of the permafrost, the situation only gets worse as it unfolds. [...]"

Neven and all the readers of this wonderful blog, I apologize in advance for a little mostly off-topic stuff, but I have just written three blog posts on climate science and its implications for global warming, mainly because I have been unable to find a similar comprehensive explanation elsewhere. However, I am not a scientist. I would appreciate anyone who feels competent going to waynekernochanblog.blogspot.com, reading Parts I and II of the three-post series (Part III does not depend on accurate descriptions of the science), and telling me where you believe it is inaccurate or misleading, hopefully citing chapter and verse. I can't promise I will incorporate your comments; but I can promise I will take them very seriously. Thanks in advance - Sincerely, Wayne

Sigh. Bill, let me run through the math, and then I'm going to drop the topic. As I understand it, exponential growth over time means that in the equation t * x ** e, e is greater than 1. If e is 1, the growth is linear. In this case, even using the 2014 figure (2.17), the growth percentage (e - 1, in our formulation) goes from approximately 0.6 over 320 ppm in the 1959-1964 time frame to 2.17 over 400 ppm in 2014. And if we average 2012-2015 the difference is even sharper. There is no way that's linear. This means that exponential growth is the null hypothesis, and projecting linear growth requires a sound physical explanation. As for physical explanations in general, frankly, it's very easy to come up with one for exponential growth and, because of the historical data, not so easy to come up with one that says exponential growth in the past but linear growth in the future. For example, if I simply noted that the population has risen and conjectured that energy consumption had remained constant and would do so in future, I'd wind up with an exponential curve turning linear in the future if and only if population growth percentages/year slowed and then wound up flat/zero. The explanation you cite simply does not support this: it may be "physical", but it is far from comprehensive, leaving out carbon emissions not the result of energy consumption, such as increased methane from increasing numbers of cows, increased black carbon from melting ice, burning of Amazon rain forests to clear cropland, and so on. And it assumes energy consumption per capita will be flat over time, which historically it has not been. The fact that developing nations begin to use far more energy per capita, and that nations like India and China are now in the developing stage suggests that exponential CO2 growth is, if anything, more likely than linear growth. Enough already. Btw, I was born in 1950 too. :)

http://www.esrl.noaa.gov/gmd/ccgg/trends/ and go to the scrollable column at the bottom left. Mauna Loa, btw, is the first and longest-running CO2 measurement. As noted in the comments, variability from the actual atmospheric CO2 increase should not be very large.