Presumed Parameters - Climate Change: Identification and Projections - page 60

The evaluation itself is in accordance with the IPCC's constant claim that,
since 1950, natural factors have only had a minimal effect of global warming 3 .
Since the variations in net irradiance are otherwise very low, just fractions of
Wm -2 , the influence on the climate would be a few hundredths of a degree,
while the impact of CO 2 can be counted in at least tenths of a degree.

Total sensitivity to solar activity

In the draft SPM, a version of which was leaked before its release 4 (p. 8,
line 41), a detailed account of climate change drivers stated that “cosmic
rays enhance aerosol nucleation and cloud condensation nuclei production in
the free troposphere, but there is high confidence that the effect is too weak
to have any significant climatic influence”.

Nevertheless, the same text adds that: “Many empirical relationships have
been reported between GCR or cosmogenic isotope archives and some
aspects of the climate system […] but the forcing from changes in total solar
irradiance alone does not seem to account for these observations, implying
the existence of an amplifying mechanism such as the hypothesized GCR 5 -
cloud link”. However, it later (Chapter 10) states “high confidence that the
effect of changes in solar irradiance are much smaller than the climatic
changes resulting from a rise in radiative forcing due to GHGs”.

The expression “amplifying mechanism” gives rise to confusion: it
suggests that an amplification could act specifically on the solar energy flow,
whereas “amplifying mechanisms” are common to all radiative forcing,
through the common reaction coefficient , the sum of all climate

reactions, whether positive or negative (see section 4.2). The “hypothetical
link” between the GCRs and clouds would therefore not be a mechanism
which amplifies the irradiance, but an alternative mechanism of solar action.
The link to GCRs is mentioned several times in the AR5, without ever
alluding to the CLOUD experiment (Kirkby, 2011, Almeida, 2013), carried
out at CERN from 2009 to 2011 by around fifteen different institutes.
Finally, the reference above to observations, correlations and GCRs was
deemed inconvenient by the IPCC, and was removed from the final version

λ

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3 See “ Change in solar irradiance” , figure SMP. 5.
4 http://www.stopgreensuicide.com/SummaryForPolicymakers_WG1AR5-SPM_FOD_Final.pdf.
5 Galactic Cosmic Rays, which we know are affected themselves by solar magnetism.