SODBatch A&B SPM Comments co-chair response final ... - ipcc-wg3

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Comments
IPCC WGIII Fourth Assessment Report, Second Order Draft
(Government of UK)
A 5 1 5 1 It is good to learn that it is technically feasible to stabilise GHG
concentrations in the atmosphere, even at levels as low as around
450 ppmv CO2eq. However, it would be very relevant to inform the
reader also whether such scenario would still be economically
feasible or not. It is suggested to insert "and economically feasible
from a global perspective" after "technically feasible". This is to
indicate that such scenario might need imply significant changes at
the regional or local scale or for some sectors. However, it is noted
that there seems to be little evidence for such statement (see para 7
of SPM on page 8). A solution could be to link this statement to
those CO2-levels for which such statement can be made
(concentration in the range of 550 ppm) and to indicate that
stabilisation at 450 seems technically feasible (and not indicating
that it is also economically feasible). It might be useful to indicate
also the potential of the need of overshooting because the potential
of substitution of fossil fuels by biomass seems to be uncertain as
indicated in para 23 on page 14 of the SPM.
(Government of Austria)
A 5 1 5 2 Indicate what the relevance is of the 450 ppmv CO2-eq stabilisation
level for the layman (e.g. compared to pre-industrialized levels)
(Government of European Community / European Commission)
A 5 1 5 2 Add "in the long-term" or "by 2xxx" after "in the atmosphere".
(Government of European Community / European Commission)
A 5 1 5 6 The definition of "technically feasible" is vague. In Section B it
seems that GHG concentrations in the atmosphere can be stabilized
solely by mitigation technology. However, in reality, GHG
mitigation is realized through both technological and non-
Expert Review of Second-Order-Draft
Confidential, Do Not Cite or Quote
Response suggested by cochairs
REJ; economically feasible”
would be a value judgement that
IPCC cannot give
ACC footnote
REJ; superfluous
TIA; heading text to be deleted,
but wording to be used for
merging with para 6
Action
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chapter
Considerations
by the writing
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Page 85 of 348