Physics Today: Is climate sensitive to solar variability? (HT: Planet Gore)
…The nonequilibrium thermodynamic models we used suggest that the Sun is influencing climate significantly more than the IPCC report claims. If climate is as sensitive to solar changes as the above phenomenological findings suggest, the current anthropogenic contribution to global warming is significantly overestimated. We estimate that the Sun could account for as much as 69% of the increase in Earth’s average temperature, depending on the TSI reconstruction used.5 Furthermore, if the Sun does cool off, as some solar forecasts predict will happen over the next few decades, that cooling could stabilize Earth’s climate and avoid the catastrophic consequences predicted in the IPCC report.
This study was funded by an Army Research Office Grant. I had no idea that the Army was now working for Exxon. 🙂
In related news, the BBC did an article back in July 2004, Sunspots reaching 1,000-year high:
Scientists based at the Institute for Astronomy in Zurich used ice cores from Greenland to construct a picture of our star's activity in the past.
They say that over the last century the number of sunspots rose at the same time that the Earth's climate became steadily warmer.
The warming is being amplified by gases from fossil fuel burning, they argue.
Sunspots have been monitored on the Sun since 1610, shortly after the invention of the telescope. They provide the longest-running direct measurement of our star's activity.
The variation in sunspot numbers has revealed the Sun's 11-year cycle of activity as well as other, longer-term changes.
In particular, it has been noted that between about 1645 and 1715, few sunspots were seen on the Sun's surface.
This period is called the Maunder Minimum after the English astronomer who studied it.
It coincided with a spell of prolonged cold weather often referred to as the "Little Ice Age". Solar scientists strongly suspect there is a link between the two events – but the exact mechanism remains elusive. …
Meanwhile, meteorologist Anthony Watts has been updating the Sun's present cycle. The Ap magnetic index measures magnetic activity from the Sun, strongly correlated with sunspot activity. As I understand it, we've reached a cyclical minimum and are due for an upswing in activity this month. However, concerning the Ap magnetic index, Watts writes:
This is the one that worries me though, as I’ve pointed out before, we have that step function (or discontinuity) in 2005 (see red arrows) which gives the impression that something just “switched off” in the solar magnetic dynamo:
See here we are on March 18, 2008. What does the Sun look like?
(Source: SOHO)
Spotless! Stay tuned.
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