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Deep Solar Minimum
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Is Something Happening To The Sun?

By James Donahue

With all of the expressed concern about global warming brought on by greenhouse gas emissions from cars and industry, little notice has been given to a group of astrologers and solar physicists who are warning that some significant changes are occurring on the sun.

Some are saying these solar changes, which include a reduction in sun spots, irradiance, solar wind and radio emissions, may be signaling the start of a new ice age, or at least a looming period of colder than usual temperatures around the globe.

Finnish physicist Timo Niroma notes that the sun goes through regular cycles of activity about every 12 years. The current “Twenty-Third Cycle,” however, which began with a lot of solar activity, has now trickled down to long periods of no sun spots, reduced brightness, and a generally quiet sun. Niroma says there is an appearance that the next cycle will have a very weak beginning, or may be delayed, thus imitating something solar physicists have dubbed the Maunder minimum.

The Maunder minimum, or a prolonged sunspot minimum, marks a period from 1645 to 1715 when solar observers noted that sunspots were unusually rare. Solar astronomer Edward W. Maunder noticed how sunspot latitudes changed with time. He published two papers in which he and other researchers like Gustav Sporer, John A. Eddy and John Dalton noted that these minimum sunspot periods coincided with a period of lower-than-average global temperatures on Earth.

During one such minimum period, from 1790 to 1830, now dubbed the Dalton Minimum, the Oberlach Station in Germany recorded a two degree Celsius decline in temperatures over a 20 year period. The year 1816, which fell within this period, was known as “The Year Without a Summer.” Temperatures throughout the Northern Hemisphere were so low that crops failed and many people starved and froze to death.

To be fair, 1816 was a year when a major volcanic eruption of Mount Tambora, on the island of Sumbawa, Indonesia, also was partially blamed for the dynamic weather event. Volcanic ash was said to have caused a global cooling for months after the eruption.

One observer recently wrote that from his observations “it appears that the sun has slowed its internal dynamo to a similar level such as was seen during the Dalton minimum.” He noted that this minimum period began with a skipped solar cycle, which may be happening now.

How bad has it been? NASA reports that during 2008 there were 266 of the year’s 366 days when there were no sunspots observed. During the early months of 2009, the number of sunspots have dropped even lower.

Solar physicist Dean Pesnell of the Goddard Space Flight Center said he believes “we’re experiencing a very deep solar minimum.”

The NASA space records also show that the sun’s brightness has dropped by 0.02 percent at visible wavelengths and 6 percent at extreme UV wavelengths since 1996. Scientists say the changes are not enough to reverse the course of global warming, however.

A series of articles in the Huffington Post on the subject by Bill Chameides examined the possibilities that the solar activities may signal a future cooling of the planet that will counteract man-made global warming.

Chameides, who is dean of Duke’s Nicholas School of the Environment and a member of the National Academy of Sciences, noted that it appears obvious that past solar activities have had an effect on the world’s climate.  In his articles, he also addresses arguments by some that the sun may also be causing global warming. To this, Chameides notes that “one cannot attribute the lion’s share of global warming in the last 30 years to changes in the sun’s energy output.”

Chameides identifies sunspots as “areas of strong magnetic fields on the surface of the Sun. They are caused by disruptions in the Sun’s magnetic field.” Beyond this, no one understands the link between the appearance of these spots on the Sun and the weather patterns on Earth.

He writes that in addition to greenhouse gases and solar events, things like El Nino and La Nina oscillations over the oceans all play a part in affecting the world’s weather. But the constant heating of the planet and the obvious affect this is having on changing weather patterns has not stopped in spite of the reduction in solar activity.

Chameides notes that ice ages have occurred on Earth in the past and another one is “almost certainly in our planet’s future.” But he warns against speculation that a solar minimum appearance of sunspots is signaling a cooling trend that will offset the deadly effects of global warming at this time.

“Would I be willing to bet my children’s and grandchildren’s future on that possibility? No.” he concludes.