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View Diary: European Space Agency's CryoSat-2 satellite: Antarctica shedding 160 billion tonnes of ice a year (56 comments)

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  •  Shape of the curve (8+ / 0-)

    Notice that the time to maximum CO2 from previous minimum is relatively much shorter than the time from maximums to relative minimums. This means that the increasing mechanisms are faster than the decreasing mechanisms, not good for us. It takes along time on the average for the planet to absorb high levels of CO2, and these "high levels" are much less than the current anthromorpic era.

    WAIS is past its tipping point. The general principle here is that there is a lot of change already built in. We are both nowhere near equillibrium and we are nowhere close to decreasing the yearly increase in CO2, in fact it looks to me like the second derivative is locally positive.

    If you want to know when to panic, it's now. The concept that we must do something "in the future" to avoid global warming is dead. The future is way too late. What we are dealing with now is limiting the ultimate intensity of the coming climate catastrophe(s).

    •  even if we altogether stopped (6+ / 0-)

      burning and clearcutting, the temperature and melting trends wouldn't slow overnight. we can still reduce the level of damage, and that's what the target co2 levels are about. but we're not going back to the old normal.

      The cold passion for truth hunts in no pack. -Robinson Jeffers

      by Laurence Lewis on Mon May 19, 2014 at 11:19:10 AM PDT

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    •  The shape of the curve is glacial... (3+ / 0-)
      Recommended by:
      Roger Fox, The Wizard, JVolvo

      ...except for the past 200 years.

      The atmospheric CO2 curve shown is entirely from ice core studies in Antarctica and Greenland, where annual layers of snow get added each winter, and atmospheric gasses get trapped.  In a clean room, it's possible to count back the layers (with somewhat more error with time) and extract the CO2 and other atmospheric gasses and get a record of atmospheric composition with time.  

      The shape of the curve almost perfectly matches the volume of ice on the Earth over time.  Glacial cycles typically about 100,000 years, with slow buildups of continental glaciers in North America and Europe over about 80,000 years, a rapid deglaciation and about 10,000 years of relatively ice-free times.  These in turn are driven by the Milankovich cycles, changes in Earth's orbit over time.  The basic research showing this pattern was done by Jhn Imbrie, of Brown University as part of the CLIMAP project over 40 years ago.

      The last "high" carbon episode was about 120,000 to 130,000, a period of time known as the "Sangamon Interglacial", when conditions were slightly warmer than they have been over the past 10,000 years, and soils today seen in Georgia were developed in central Illinois.  Our current warm period (known to geologists as the Holocene) has been going on for about the last 7,000 to 8,000 years, although the start of the Holocene is pegged at about 10,000 years.

      With the geologic doctrine of "the present is the key to the past", the orbital cycles predict that a new ice age will begin in about 5,000 years or so, and once again, large ice sheets will grow on the continents.  The West Antarctic ice sheet will form again, and we'll continue on as before.

      And what about the current spike?  As shown by the data, it's unprecedented.  CO2 is now 33% more abundant than it ever has been over the past half million years.  Isotopically, the added CO2 is "old" carbon, long depleted of C14, and thus it's all from burning fossil fuels.

      The bad news is, all of the global warming effects are likely to occur in the short term.  The good news (from a geologic perspective) is that even if we don't stop burning fossil fuels as a matter of climate control, we'll eventually stop using them when we run out of them - in a few thousand years.  Once we've quit burning fossil fuels, the natural sinks for CO2 will start absorbing the excess, and we'll be back to "normal" in less than 10,000 years - just in time for the next ice age to start.

      Of course, that's much too long a time frame for us, our children and our grandchildren.

      The Scout Law (trustworthy, loyal, helpful...) is a GREAT liberal manifesto.

      by DaytonMike on Mon May 19, 2014 at 11:56:48 AM PDT

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