Science Made Cool

Solar Weather Forecast

According to NOAA, the next solar cycle should peak in about 2013, but with a record low number of sunspots.

The Sun follows a cycle of sunspot activity, with a roughly 11-year period between times of low activity. But the length can vary. Fewer sunspots mean fewer solar flares, less heating of the Earth's upper atmosphere, and fewer auroral displays. (The actual scale of the flares, etc., don't seem to be correlated -- as the linked article points out, one of the worst episodes of solar activity on record came during a similar low cycle.)

There's also a connection between solar activity and climate -- which is why NOAA, rather than, say, NASA, is the agency which keeps tabs on sunspots. Low sunspot activity seems to have a connection with cooler weather. The "Maunder Minimum" of the 17th Century, a period when there may have been no sunspots at all for several decades, correlates pretty neatly with the "little Ice Age" of notably cold weather in Europe.

If all this is true -- and we're talking about estimates and correlations only -- then the next few years should see warmer weather. Let's check back in, oh, 2015 or so and see how it turned out.

There Goes the Sun

Has anybody found the remote for the Sun yet? Its output is now lower than it has been at any point since 1913.

The idea of the Solar cycle dates back less than 200 years, though it stems from discoveries made in the 17th century. Bear with me: Galileo started observing the Sun around 1610 and discovered sunspots. He also went blind -- don't stare at the Sun, okay?

Anyway, in the 19th century some stereotypically methodical German astronomers, Samuel Schwabe and Rudolf Wolf, began counting sunspots and analyzing their frequency. They discovered something kind of neat: sunspots go in an 11-year cycle. Every 11 years the number of sunspots drops off to nearly zero, then starts building up again.

Right now we're in the middle of an unusually long sunspot minimum. What does this mean? Well, in good news it means less heating of the upper atmosphere, less radio interference, less solar flare risk to astronauts, and in general a quieter environment in space. On the other hand, it might plunge the Earth into an ice age. Plus no auroras.

What exactly causes this cycle is not well understood. Obviously it has something to do with how the Sun's core produced energy, or how the Sun's outer layers release that energy, but as one might imagine it's hard to study the interior of a star.

In the meantime, if you do run across the remote, turn the power back on.

Sun Down

Here's a bit of disturbing news. According to solar astronomers, the Sun's magnetic field activity is lower than it has been for decades. What does this mean? Maybe nothing. Or maybe a dip in the Sun's energy output -- leading to another Little Ice Age here on Earth.

Don't panic, and don't start hoarding guns and Polartec just yet. If the sunspot count starts to rise in the next few years, there may not be anything wrong after all. And if we are in for another cold spell -- keep in mind that the last "Little Ice Age" brought us the Renaissance, the Enlightenment, and the Industrial Revolution. Humans thrived during a major ice age with nothing but furs and fire to keep away the cold; a civilization with nuclear power and microwave popcorn should be able to get by.

A Moving Target

Climate change is hardly a new phenomenon.  Even global warming due to greenhouse gases is old hat.  How old?  A group of researchers led by University of Chicago geologist Nicolas Dauphas have been studying some of the oldest rocks on Earth, looking for clues about ancient climate.

They examined rocks from the Canadian Shield -- some of the oldest crust, exposed to view by the action of glaciers during the comparatively recent Ice Ages.  These rocks are about 3.75 billion years old, making them remnants of the first solid crust of the Earth.

What they found was consistent with an atmosphere very rich in carbon dioxide.  Earth in those days had a very high greenhouse effect, which was a Good Thing because the Sun was a lot cooler than it is now -- only 75 percent as bright.  Without a greenhouse atmosphere to trap heat, Earth would have gone through a runaway cooling, leaving it a completely ice-covered world with a few volcanic hot spots.

The story gets interesting after that.  About half a billion years after those Canadian rocks were laid down, living things began to make massive changes to the Earth's environment with waste gases, and nearly made the planet uninhabitable.  Who were the polluters?  Algae. 

Algae and plants using photosynthesis completely transformed the Earth's atmosphere.  The carbon dioxide levels dropped like a rock as they turned it into biomass.  Predictably, the temperature dropped like a rock soon after.  Some scientists are convinced the Earth spent a considerable time completely covered in ice -- the "snowball Earth" model.  Others think conditions may have only been as bad as the more recent Ice Ages.  Either way, it was only the increase in the Sun's energy output which rescued the planet from a chilly fate.

All this is by way of pointing out that climates do change, all the time.  Life and the planet adapt.  It is impossible to prevent the Earth's climate from changing, which means that humans really should be thinking about how we want the climate to change and what trade-offs we're willing to make.

The Improved Crystal Ball

The National Weather Service is now providing climate estimates up to a year in advance.  Either they're very confident or this is all some very complicated meteorological prank which will have them snickering for weeks.  Anyway, go here to check out your climate for the next twelve months.

Climate Change anyone?

For those who want to delve a little deeper into climate change issues, check out RealClimate . Eric Steig, brother of Zygote founder Joseph Steig, is a contributor  to the site. We don't have a climate change game yet but it's an interesting notion . . .