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The Times Notices the Solar Minimum

Weather eye: The Sun may have had the strangest weather of last year - Times Online

The solar minimum could also be cooling the climate on Earth because of slightly dimished solar irradiance. In fact, the quiet spell on the Sun may be masking some of the warming effects of greenhouse gases, according to recent research by two US solar scientists. The solar minimum, their study suggests, accounts for the somewhat flat temperature trend of the past decade. But even if this solar minimum is offsetting global warming, scientists stress that the overall effect is relatively slight and certainly will not last.

The Sun has gone into long quiet spells before. From 1645 to 1715 few sunspots were seen during a period called the Little Ice Age, when short summers and savage winters often plagued Northern Europe. Scotland was hit particularly hard as harvests were ruined in cold, miserable summers, which led to famine, death, migration and huge depopulation. But whether the quiet Sun was entirely to blame for it remains highly uncertain.

Heresy! I note that unusually for a Times Weather article it is anonymous. Is Paul Simons away? He was peddling the Carteret Island myth on 30th Dec, maybe he is stuck in the ice.


Re: "But even if this solar minimum is offsetting global warming, scientists stress that the overall effect is relatively slight and certainly will not last."

Not all scientists agree.
You may be interested in reading one scientific treatise that discusses the effects of Sun activity on the Earth’s environment and in particular climate variation. See at this URL. http://www.winningreen.com/site/files/621/52299/206275/277668/Sun&ClimChge.pdf
If you do not relish wading through the voluminous complex calculations, please consider the Conclusions on page 15 quoted below.

Some of the arguments and data behind the contention that the earth’s climate could be
affected by changes in cloud cover caused by variations in the galactic cosmic ray flux have been
briefly summarized. These data strongly imply that a relation between cosmic rays intensity and
cloud cover may explain how relatively small changes in solar activity can produce much larger
changes in the earth’s climate. While the correlation is robust, there is still no generally accepted
mechanism, although a number have been proposed. This is not surprising since the
microphysical processes in clouds are quite complex and this is an ongoing area of research.
Nevertheless, a lack of an accepted microphysical process for increasing cloud condensation
nuclei does not justify minimizing the impact of solar variations on climate.
A simple, phenomenological approach was used to obtain two estimates of the fraction of
the global temperature rise since 1900 due to a rise in solar activity. These methods yield a value
of 36-50% for the solar fraction. This value is consistent with other estimates in the literature.
According to the 2007 IPCC Summary for Policymakers, essentially all of the
anthropogenic radiative forcing since 1750 is due to the increase in carbon dioxide concentration.
This means that if the sun is responsible for 36-50% of the temperature rise since 1900, the IPCC
is using too large a value for its coefficient relating radiative forcing to changes in carbon dioxide
concentration. This is important because a smaller value of αreduces the sensitivity of the
earth’s climate to increases in carbon dioxide concentrations—a result that has significant policy implications.”

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