Nature: Declining solar activity linked to recent warming

[bystander]

Declining solar activity linked to recent warming
Nature News | 06 Oct 2010

The Sun may have caused as much warming as carbon dioxide over three years.

Waning solar activity between 2004 and 2007 has unexpectedly been linked to a warmer Earth. [i](Credit: Science Photo Library)[/i]

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An analysis of satellite data challenges the intuitive idea that decreasing solar activity cools Earth, and vice versa. In fact, solar forcing of Earth's surface climate seems to work the opposite way around — at least during the current Sun cycle.

Joanna Haigh, an atmospheric physicist at Imperial College London, and her colleagues analysed daily measurements of the spectral composition of sunlight made between 2004 and 2007 by NASA's Solar Radiation and Climate Experiment (SORCE) satellite. They found that the amount of visible light reaching Earth increased as the Sun's activity declined — warming the Earth's surface. Their unexpected findings are published today in Nature.

The study period covers the declining phase of the current solar cycle. Solar activity, which in the current cycle peaked around 2001, reached a pronounced minimum in late 2009 during which no sunspots were observed for an unusually long period.

Sunspots, dark areas of reduced surface temperature on the Sun caused by intense magnetic activity, are the best-known visible manifestation of the 11-year solar cycle. They have been regularly observed and recorded since the dawn of modern astronomy in the seventeenth century. But measurements of the wavelengths of solar radiation have until now been scant.

An influence of solar spectral variations on radiative forcing of climate - JD Haigh et al

• Nature 467 696 (07 Oct 2010) DOI: 10.1038/nature09426

Study sheds new light on how the Sun affects the Earth's climate
PhysOrg | Earth Sciences | 06 Oct 2010

Sun's activity flies in face of climate expectations
New Scientist | Environment | 06 Oct 2010

Sun's Surprise: Even As It Relaxes, It May Heat Earth's Climate
Space.com | Science | 06 Oct 2010

[neufer]

Declining solar activity linked to recent warming
Nature News | 06 Oct 2010

Joanna Haigh, an atmospheric physicist at Imperial College London, and her colleagues analysed daily measurements of the spectral composition of sunlight made between 2004 and 2007 by NASA's Solar Radiation and Climate Experiment (SORCE) satellite. They found that the amount of visible light reaching Earth increased as the Sun's activity declined — warming the Earth's surface. Their unexpected findings are published today in Nature.

The study period covers the declining phase of the current solar cycle. Solar activity, which in the current cycle peaked around 2001, reached a pronounced minimum in late 2009 during which no sunspots were observed for an unusually long period. Sunspots, dark areas of reduced surface temperature on the Sun caused by intense magnetic activity, are the best-known visible manifestation of the 11-year solar cycle.

I was under the impression that it has been known for a long time that sunspots reduced
the visible output of the sun (by about 0.1%); however the ultraviolet output increases by about 10%.

[BMAONE23]

We might not have to worry about that now
http://www.larouchepac.com/node/16011
http://www.eworldpost.com/europe-is-exp ... 15546.html

[neufer]

Solar irradiance through June 2010 (from Fröhlich & Lean 2004, and PMOD/WRC)

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