the Air Vent

Because the world needs another opinion

WUWT Cloud Creation

Posted by Jeff Id on July 1, 2009

Everyone who hasn’t seen the slide show on cloud aerosol should take a look at this post at WUWT.

6 Responses to “WUWT Cloud Creation”

  1. Hal said

    Great slide show

    Completely off-topic, I ran across this, where a a few guys searched the AGW literature about tipping points and decided to publish a paper about:

    “Imprecise probability assessment of tipping points in the climate system”

    here is the abstract:

    Major restructuring of the Atlantic meridional overturning circulation, the Greenland and West Antarctic ice sheets, the Amazon rainforest and ENSO, are a source of concern for climate policy. We have elicited subjective probability intervals for the occurrence of such major changes under global warming from 43 scientists. Although the expert estimates highlight large uncertainty, they allocate significant probability to some of the events listed above. We deduce conservative lower bounds for the probability of triggering at least 1 of those events of 0.16 for medium (2–4 °C), and 0.56 for high global mean temperature change (above 4 °C) relative to year 2000 levels.

    The best that they can say about their work is that it is imprecise..

    I probably should have put this into the prediction folder, but I won’t be around when these probabilities potenntially become fact.


  2. John D said

    I noticed on WUWT that attention was called to the divergence between the temperature and isotope lines in the most recent segment of one of the charts. What I thought interesting is that while the discussion seem to focus on the divergence of temperature, there is a divergence between the isotopes as well. That suggests that something has changed in the production of light isotopes in the recent past. Since these are believed to be produced by cosmic ray bombardment, the nature of the cosmic rays seems to have changed. I would really appreciate someone who understands the theory better addressing that fact.

  3. Amabo said

    The idea that the nature of cosmic rays has changed seems rather unlikely.

  4. John D said

    You’re right of course. I was thinking that a shift in the energy distribution of incoming cosmic rays (they’re all cosmic rays, but the energy spectrum extends from 10^8 to about 10^21 eV) may have taken place in the recent past. Unfortunately early mornings are not the best time to write for me and clarity can suffer. Another alternative is that the mix of precursors to the light isotopes in the atmosphere has changed in composition, leading to a change in isotope production under normal bombardment rates. Regardless, the two light elements produced by cosmic rays are closely coupled up until the recent past on that graph. Then, at the same time that the temperature curve seems to depart from the former pattern of correlation, so does the relative production abundance of those two isotopes.

  5. DeWitt Payne said

    A quick search finds that 14C is created by radiation emitted by the sun and 10Be is formed by galactic cosmic rays. Shaviv’s hypothesis was that the sun modulates both kinds, but internal galactic rotation relative to the sun also modulates galactic cosmic rays. So the formation rates of the two isotopes can, in principle, vary independently.

  6. Amabo said

    I guess the problem with this hypothesis is how easy or hard it will be to test. If this change in the energy distribution happened in the 18-somethings, how likely is it to have been reported, or event noticed, etc.

    A theoretical case could probably be built from it, I don’t have the know-how of cosmic radiation to make a statement one way or the other…

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