physically bizarre. (The WMO report did not take it seriously, so their expert judgment can be relied on in this respect.) In an assessment such as this SAP, good information should be sifted from the bad. To be fairly considered, this information should be presented with an assessment of its reliability.

  • P. 12, L. 248-260: These three bullets should either be expanded upon, moved, or eliminated. The first bullet uses the term “EESC” and mentions “different scenarios” again without explaining these concepts. In fact, the first sentence of the first bullet is incorrect because changes in CH4 and N2O and climate will dominate the future UV trend; furthermore, using the term “more dominated” is confusing and raises the question of more dominated in comparison to what? The second bullet talks about “the new method”, but it is not clear what this is or why it is important or different from a previously used method. The third bullet appears to be a partial restatement of information on P. 7 and 9.

  • P. 12, L. 260: “The (Special Report on Emissions Scenario) SRES A1B scenario” is not helpful without an explanation of this “scenario” and its source. Why not give a range of outcomes beyond just one scenario?

  • P. 12, L. 268 - P. 13, L. 278: How can ozone in midlatitudes increase if it is influenced by Arctic springtime total ozone values that have been lower than 1980 values? These two bullets seem to present a contradiction.

  • P. 13, L. 274-275: What is the basis for the statement that a significant part of the midlatitude ozone decreases over the U.S. have come from the Arctic?

  • P. 13, L. 280-284: This sentence is repeated almost verbatim from P. 9, L. 176 -P. 10, L. 181.

  • P. 13, L. 286: Are the effects “masked”, or is it just that the signal is too hard to discern from the noise and instrument uncertainties?

  • P. 13, L. 288-292: This bullet should include not just U.S. emissions but also production of ODSs by U.S. companies.

  • P. 13, L. 289-291: Perhaps the intended meaning of this sentence is better conveyed by rewriting it as follows: “The U.S. has also contributed to … attenuating surface UV changes, and mitigating the radiative forcing of the climate”.

  • P. 14, L. 293-295: The accuracy of this statement depends on how much of the bank gets released.

  • P. 14, L. 301-306: This bullet should also discuss radiative forcing.

  • P. 14, L. 304: Change “would have had” to “would have resulted in”.


In Chapter 1 of the draft SAP, the background information on ozone should be expanded and revised to accommodate readers who may not have technical knowledge in this area. The committee provides some suggestions below for improving the presentation of this background information.

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