Short-term Predictions - Climate Change: Identification and Projections - page 117

Let us now study the bundle determined by Meehl and Teng (oblique
hatching area), using an initialization updated in 2006. Although at the time
the stagnation was hardly perceptible, it had already started, and
the re-initialization could (or should) have provided a bundle of predictions
able to remain accurate for at least 6 years, before being proven invalid by
observations.
These failures are explained by the stance taken by the IPCC. It maintains
that the dramatic rise seen up until 2000 is largely due to the anthropogenic
factor, with the natural fluctuations deemed insignificant, and the volcanic
factor even having some effect in the opposite direction. Curiously enough,
on the medium white line in graph (b), there is no perceptible contribution
from the Schwabe cycles. According to the correlation established by Camp
(not to mention ours), solar activity could have contributed to some extent to
the climate pause observed during the last decade. As weak - and likely - as
it may be, such a contribution of solar activity to the climate pause would
contradict the theory on the anthropogenic origin of the warming. This
would be due not so much to its amplitude over the period 2000-2010, as to
the fact that the high frequency/low frequency ratio of the models' dynamic
(EMB or GCM) would imply an equilibrium solar sensitivity which could
explain all or part of the warming observed over the 20 th Century. It is
understandable why the IPCC prefers to ignore the immediate role of the sun
in the climate pause, however small it may be.
In this context, the IPCC can only attribute the current climate pause to a
negative fluctuation in the climate's natural variability which should come to
an end sooner or later. This clearly appears on the projection bundle by
Smith et al . (vertical hatching area), which predicts, after 2013, a return to
strong temperature increases.
11.2. The climate's natural variability
Climatic variations (and especially variations in global temperature)
result either from duly identified causes, or from phenomena assumed to be
negligible (the geothermal flow), or from causes omitted because of a lack of
sufficient scientific data (geomagnetism), or simply those which are as yet
unknown. They are also caused by anything with random attributes, intrinsic
to the turbulent (chaotic) nature of tropospheric and oceanic flows, known as
internal variability .