Greatly Decreased Solar Radiation

An article in The Independent on 27 April 2009 called "The missing sunspots: Is this the big chill?" notes that the current decrease in solar activity and the reduced radiation due to it is more important than many scientists had thought. Marc Hairston of the University of Texas says of the solar inactivity "This is the lowest we've ever seen. We thought we'd be out of it by now, but we're not."

There is also the so-called solar wind – streams of particles the Sun pours out – that is at its weakest since records began. In addition, the Sun’s magnetic axis is tilted to an unusual degree. “This is the quietest Sun we’ve seen in almost a century,” says NASA solar scientist David Hathaway. But this is not just a scientific curiosity. It could affect everyone on Earth and force what for many is the unthinkable: a reappraisal of the science behind recent global warming.

The article also provides an interesting history of man's observances of sunspot activity:

Sunspots are dark, cooler patches on the Sun’s surface that come and go in a roughly 11-year cycle, first noticed in 1843. They have gone away before. They were absent in the 17th century – a period called the “Maunder Minimum” after the scientist who spotted it. Crucially, it has been observed that the periods when the Sun’s activity is high and low are related to warm and cool climatic periods. The weak Sun in the 17th century coincided with the so-called Little Ice Age. The Sun took a dip between 1790 and 1830 and the earth also cooled a little. It was weak during the cold Iron Age, and active during the warm Bronze Age. Recent research suggests that in the past 12,000 years there have been 27 grand minima and 19 grand maxima.

Throughout the 20th century the Sun was unusually active, peaking in the 1950s and the late 1980s. Dean Pensell of NASA, says that, “since the Space Age began in the 1950s, solar activity has been generally high. Five of the ten most intense solar cycles on record have occurred in the last 50 years.” The Sun became increasingly active at the same time that the Earth warmed. But according to the scientific consensus, the Sun has had only a minor recent effect on climate change.

It would seem reasonable to believe that the warming trend overall of the period following the end of the Little Ice Age might be due to the unusually active Sun of that period. But, no the great computer models of the climate have claimed that that was only so prior to 1950, but that after that time greenhouse gas effects were dominant. Strange that the most intense solar activity observed was post 1950, lasting to the end of the century. Nonetheless, the very inaccurate climate computer models have claimed that the solar effect is responsible for only 10 to 50% of the warming, with most of them claiming the lower end of that range.

The article notes that the Sun's radiation output varies by about 0.1 percent during the 11-year solar cycle, which is small, but the total energy involved is huge. This is about 1.3 W/sq.m. at the ground, which recent investigations have shown causes some strong regional climate changes.

What strikes me as very noteworthy is that there could be no more obvious a natural factor to the Earth's climate than the varying input of the sun. Despite that and the huge claims made with respect to the greenhouse gas effects of CO2 in the atmosphere, climatologists are clearly not on top of an understanding of the climate effects of the Sun. The computer modelers have clearly overestimated the effects of CO2, which is still increasing, despite a lack of warming since 1998. The overestimation of the greenhouse effect due to CO2 is also clearly revealed in the much lower temperatures of the atmosphere as a function of altitude compared to the predictions of the computer models. It seems clear to me that the radiative output changes of the Sun are actually playing the more important role. At least this is where I would invest my time in improving the computer models for moderately long-term climate changes, if that were my business.