Astronomers Forecast Spotless Sun—A New Little Ice Age to Come?

Yesterday, at the annual meeting of the American Astronomical Society, researchers released three new studies strongly suggesting that solar sunspot activity will abate considerably for the foreseeable future. As Space.com reports:

"The solar cycle may be going into a hiatus," Frank Hill, associate director of the National Solar Observatory's Solar Synoptic Network, said in a news briefing today (June 14).

The studies looked at a missing jet stream in the solar interior, fading sunspots on the sun's visible surface, and changes in the corona and near the poles.

"This is highly unusual and unexpected," Hill said. "But the fact that three completely different views of the sun point in the same direction is a powerful indicator that the sunspot cycle may be going into hibernation." …

"If we are right, this could be the last solar maximum we'll see for a few decades," Hill said. "That would affect everything from space exploration to Earth's climate."

Ah, the vexed question of the effect of solar variations on Earth's climate. One widely accepted explanation for the advent of the Little Ice Age is the reduction of solar activity (fewer sunspots) that occurred during the Maunder Minimum between 1645 and 1715. As the Cosmic Log over at MSNBC reports:

Storms from the sun are expected to build to a peak in 2013 or so, but after that, the long-range indicators are pointing to an extended period of low activity — or even hibernation.

"This is important because the solar cycle causes space weather … and may contribute to climate change," Frank Hill, associate director of the National Solar Observatory's Solar Synoptic Network, told journalists today.

In the past, such periods have coincided with lower-than-expected temperatures on Earth. The most famous example is the Maunder Minimum, a 70-year period with virtually no sunspots from 1645 to 1715. Average temperatures in Europe sank so low during that period that it came to be known as "the Little Ice Age."

The linkage between solar activity and climate change is still a matter of scientific debate. And even if there is a link, it's not clear how solar-caused global cooling might interact with industrial global warming due to greenhouse-gas emissions. Climate scientists say the swings in solar activity that they've studied so far have had little or no impact on temperatures or other climate indicators — and they don't expect to see a big impact even if the sun goes quiet for a decade or longer. …

Hill and two other solar physicists involved in formulating the forecast, NSO researcher Matt Penn and Richard Altrock of the U.S. Air Force's coronal research program, said there was not yet enough data to firm up a climate connection to solar activity. But they and other scientists have noted that historic lulls in sunspots, such as the Maunder Minimum and another solar minimum between 1790 and 1830, coincided with cooler temperatures.

Goddard Space Institute climatologist and fierce global warming proponent Gavin Schmidt tells MSNBC:

…the effects of solar activity on climate over the past 30 years have been "at the margin of what we can detect."

"They are detectable in the high atmosphere, but when you get down to the surface, there is so much other stuff going on that it's been really hard to get a clean signal."

Well, if the sunspot forecast turns out to be accurate, then climatologists and solar physicists will have a great opportunity to figure out just how much variations in solar activity really do affect the Earth's climate. Stay tuned.