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Lack Of Sun Activity Could Bring New Ice Age Sun Seems Eerily Calm Andrea Thompson The sun's surface has been fairly blank for the last couple of years, and that has some worried that it may be entering another Maunder minimum, the sun's 50-year abstinence from sunspots, which some scientists have linked to the Little Ice Age of the 17th century. Could a new sunspot drought plunge us into another decades-long cold spell? It's not very likely, says David Hathaway a solar physicist at NASA's Marshall Space Flight Center in Huntsville, Ala. The question came up after an international solar conference held last week at Montana State University, where scientists discussed the dearth of solar activity in the last couple years.
(Article continues below) "It continues to be dead," said Saku Tsuneta with the National Astronomical Observatory of Japan and program manager for the Hinode solar mission. "That's a small concern, a very small concern," because the period of inactivity seems to be going on longer than normal. Some scientists think such inactive periods, such as the Maunder minimum, are responsible for cold spells in the past, such as the Little Ice Age. The sun's energy drives all climate and weather on Earth. And Hathaway does agree there are good indications that fluctuations in solar output related to sunspot cycles influence the Earth's climate. And the Maunder minimum isn't the only evidence — scientists have linked two smaller sunspot minimums (periods of time with very few sunspots) in the early 19th century to cold spells, as well as periods before the Maunder minimum deduced from tree ring records, he said. But the sun isn't the only thing that influences our climate: volcanic eruptions, large-scale phenomena such as El Nino, and, more recently, the accumulation of greenhouse gases in the atmosphere also affect the global climate. Prior to the industrial revolution, the sun probably accounted for about 10 to 30 percent of climate variability, Hathaway told SPACE.com, but now that greenhouse gases have started to build up, "the sun's contribution is getting smaller and smaller," he added. Short solar cycle? Solar cycles are the ebb and flow of the sun's magnetic activity over a roughly 11-year period, which affects the formation of solar features such as solar flares and sunspots. Sunspots are cooler, dimmer areas on the sun's surface. The last solar cycle, which peaked in 2001, was a particularly intense one, with an upsurge in solar storms between 2000 and 2002. Such intense activity in the peak of the solar cycle tends to lead to less activity at the end of the cycle. Signs of the current, new solar cycle (which actually overlaps with the last cycle) showed up in November 2006, and its first sunspots were seen in January of this year, and again in April, Hathaway said. So already that rules out another Maunder minimum, Hathaway says, since this solar cycle has already begun producing spots, even if there haven't been many of them yet.
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