Government Comments on the Final Draft of the SPM IPCC Working ...

<strong>Government</strong> <strong>Comments</strong> on the Final Draft of the SPM
IPCC Working Group I Fourth Assessment Report
Batch
Page:line
No.
From To Comment
[Govt. of Australia (Reviewer’s comment ID #: 2002-127)]
SPM-840 A 13:30 13:32 The first sentence places the dominant emphasis on 'uncertainty' and not on what is known. TS page 45 lines 50-55
characterise a more definite and clear presentation of the issue, which should be reflected here.
[Govt. of Australia (Reviewer’s comment ID #: 2002-128)]
SPM-841 A 13:30 13:35 A large number of studies and scientific literature indicate that if average global surface temperature rises by more than 2°C
above its pre-industriel level, the risks to ecosystems and human societies increase sharply. Reducing this risk would require
that the CO2 concentration be stabilized below 400-450 parts per million. This is notably the basis for the European Union
position on long term reduction targets. It would be very helpful that the SPM addresses this question and also clarifies by
when such a 2°C increase would be reached under various scenarios . This is all the more important since this is a crosscutting
themes of AR4.
[Govt. of Belgium (Reviewer’s comment ID #: 2003-60)]
SPM-842 A 13:30 13:35 This bullet is very complex and needs to be simplified, particularly the second sentence. For example, suggest, at line 32,
saying "...require additional reductions…" and then also changing line 34 to read "…feedback, of 105 to 300 GtC and of 165
to 510 GtC..."
[Govt. of Canada (Reviewer’s comment ID #: 2004-57)]
SPM-843 A 13:30 13:35 Awkwardly written paragraph. Also, it does not address the subject in the bolded heading so it is not clear to the reader why
this paragraph is here. IF used, suggest rewording as follows: The magnitude of the positive feedback between climate change
and the carbon cycle is uncertain. This leads to uncertainty about how to achieve any particular atmospheric CO2 stabilization
level.
[Govt. of Canada (Reviewer’s comment ID #: 2004-58)]
SPM-844 A 13:30 13:35 Feedbacks with Climate. This is a very important and critical analysis that should be expanded. Increase risk of positive feedback
should be described in terms of ocean vs land feed backs and within the component (oceand/land) an assessment of
potential risks of positive (or negative) feed backs should be highlighted. For example in the case of land the role of
permafrost melting and increase of soil organic carbon oxydation or increase of fires should be synthetized at least with their
uncertainties.
[Govt. of Italy (Reviewer’s comment ID #: 2012-24)]
SPM-845 A 13:30 13:35 Line 34 states ”450 and 1000ppm”, however, a state of “ppm” is not clear to indicate if it is of a unit of CO2 concentration or
of a one of GHG concentration in CO2 equivalent. It may confuse policy makers.
In order to avoid confusion, please clearly state the unit for instance, ppm(CO2) or ppm(GHG) throughout SPM.
[Govt. of Japan (Reviewer’s comment ID #: 2013-20)]
SPM-846 A 13:30 13:35 This paragraph covers some complex concepts. It would be more useful to policy makers if the meaning of the paragraph was
clarified. Our suggestion is: "The magnitude of the positive feedback between climate change and the carbon cycle is
uncertain. This leads in turn to uncertainty over the atmospheric concentrations that will result from particular emissions
scenarios. A number of models suggest that cummulative emissions in the 21st century require to be 105 to 300 Gt lower
because of this positive feedback, than without this feedback, to stabilise at 450 ppm. To stabilise at 1000 ppm emissions
require to be 165 to 510 Gt lower."
[Govt. of New Zealand (Reviewer’s comment ID #: 2015-9)]
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