Special note on May 13, 2013 reading

LARGE_KC400_May13SpecialNoteReaders may have noticed that the daily average baseline value for May 13, which was originally reported on May 14 as “Too Variable”, was subsequently changed on May 15 to a value of 400.17 parts per million (ppm). The reason for this change can be understood based on how baseline data and daily average baseline values are defined.
We define baseline data to consist of periods of at least five consecutive hourly average points whose within-hour standard deviations are all less than 0.15 ppm and that agree within 0.22 ppm of each other.  Data with such high stability are expected to be representative of the larger, well mixed, background air mass and largely free of any contribution from local pollution, vegetation or volcanic activity.

When data from May 13 was retrieved early in the morning of May 14, no periods for May 13 that satisfied these conditions were found.  However, when data for May 14 was subsequently retrieved, a baseline period spanning from late in the evening of May 13 through about 5 a.m. on May 14 was identified and classified as baseline.  The portion this baseline period that occurred on May 13 averaged 400.17 ppm.   Since there was no other baseline air observed on May 13, the 400.17 ppm value was assigned as the daily average baseline for that date.

7 thoughts on “Special note on May 13, 2013 reading”

  1. This IS the most important subject…
    The thing is.
    I think it’s too late…
    To stop the cycle of Climatic Variation … and the implications … …
    In 2007 an article was published in a non academic journal,
    It exposed the CON of Carbon Offsetting … this changed Governments, Academia and green experts view!
    … by pointing out Carbon Offsetting could not be achieved by planting trees etc.
    … but there was a strategic forgetting of how Governments were misled and by who?
    … see http://www.squeakydesign.info – Carbon Cycle Explained” … I wrote it … but was not credited … there’s more …

    1. Our May 9 reading for the 24-hour period used by NOAA remains unchanged at 400.08. All readings posted are preliminary.

  2. For the record – I note you first answered Yes and then after a few days replaced it with your last answer.
    – I also note that the NOAA website showed the May 9th figure was adjusted downwards and this was reported in the LA Times “The National Oceanic and Atmospheric Administration (NOAA) revised its May 9 reading at the Mauna Loa observatory in Hawaii, saying it remained fractions of a point below the level of 400 ppm, at 399.89”
    – yes I see now for 3 days your PRELIMINARY Twitter figures crossed 400ppm (the late May13th reading, 16th & 17th)

  3. Is it my imagination, but does it not appear that the peaks shown in the 800,000 curve all seem to repeat at 120,000 years intervals and that that is where we are now, the next direction is down?

    1. Scripps geoscientist Jeff Severinghaus responds “yes, indeed, the peaks in the 800,000-year record are unevenly spaced,
      some at approximately 90,000 years (4 precession cycles) and others at approximately
      115,000 years (5 precession cycles). As for where we are now, and what is likely to happen
      in the future, the best analog is the period 440,000 years ago, when Earth’s orbit was most
      like it is today. At that time, CO2 stayed high for about 20,000 years, so by analogy, we
      are halfway through that period now. In other words, we are not about to enter a new period
      of low CO2 for another 10,000 years or so.”
      Scripps geochemist Ralph Keeling adds “also, human emissions of CO2 from fossil-fuel burning are overwhelming the natural cycling of carbon and this excess CO2 will stick around for least tens of thousands of years. It may take hundreds of thousands of years before CO2 returns to natural levels.”

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