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SYFY WIRE Bad Astronomy

No, We’re Not Headed for a Mini–Ice Age

By Phil Plait

Sheesh, the global warming denial industry is cranked—and I do mean cranked—into overdrive. The latest is a rehash of an old claim that we may be headed for a “mini–ice age” due to changes in the Sun’s magnetic activity affecting its output.

Let me be very clear: no. I’ll repeat: NO. The overwhelming majority of scientists do not think this can happen. While changes in the Sun’s activity have a very marginal effect on global warming and/or cooling, human contributions to carbon dioxide in our atmosphere completely overwhelm the Sun’s influence. It’s like tapping on your brakes as your car plunges headlong into a brick wall at 100 kilometers per hour.

This new claim comes from a presentation at a conference by Valentina Zharkova, a mathematician and scientist at Northumbria University. To be clear, she’s not predicting a 60 percent drop in the light and heat emitted by the Sun, but a drop in magnetic activity in the Sun. This has only a marginal effect on the Sun’s light/heat output. Also, if you listen to an interview with her on Radio New Zealand, you’ll hear some unusual claims, like the climates on other planets are changing due to the Sun—a red herring when it comes to climate change on Earth. She also admits at the end she doesn’t do atmospheric research, so the claim that lowered magnetic activity of the Sun can cause an ice age here on Earth is in my opinion shaky at best.

The funny thing is, I debunked this Sun-influenced cooling idea back in 2011! I’ll be interested to see if Zharkova puts out a paper on this, but even if the Sun’s magnetic activity does lower, it almost certainly won’t cause any real cooling (at best it might slow warming a bit). Read that link for the details, but here’s a synopsis:

In a nutshell, the Sun goes through an 11-year cycle of magnetic activity. When it peaks, sunspots are more common. You might think that means less heat from the Sun, since sunspots are cooler and darker. But they have bright rims (called faculae) that more than make up for the cooler interior regions. So when solar activity is high, and sunspots abound, the Sun is actually very marginally warmer.

The sunspot cycle this go-round was weak, and it may be weak in the next cycle as well. No one really knows. There has been research asking what would happen if it is weak next time and concludes it will have moderate localized effects—not global cooling. In fact, the very first line of the abstract of that paper is this:

Any reduction in global mean near-surface temperature due to a future decline in solar activity is likely to be a small fraction of projected anthropogenic warming.

I mean, how much more clear can they be? None. None more clear: The Sun only has a small effect on climate change on Earth compared with what we humans are doing.

What about the Little Ice Age, though? Some climate change deniers have been claiming for a while that the lower number of sunspots can lead to a repeat of the brutal cold snap that gripped Europe in the 17th and 18th centuries, but that’s silly. There were several factors that came into play there (including huge volcanic eruptions that magnified cooling; volcanic gases reflect sunlight and cool the Earth a wee bit), and even then the effects were localized to Europe. And even then, summers were normal; it was just that winters were extra cold.

And again, all of this is a drop in the bucket. Any cooling effects by the Sun would be on top of a much larger heating trend due to global warming. Climate scientist Gavin Schmidt put out a series of tweets showing why (similar to what I’ve written here), and don’t forget that 2015 is gearing up to be the hottest year on record, too. My Slate colleague Eric Holthaus has written about this as well, and Think Progress also has a good article on it.

Of course, the usual suspects are running with this. The Daily Mail manages to make this sound like a certain apocalypse—it almost seems as if they’re trying to obfuscate reality—and many other publications repeated the claims without looking into them much, like the Australian, the Telegraph, and UPI.

But don’t be fooled. Global warming is real, and we’re headed, literally, for a world of trouble.

Tip o' the thermometer to Hot Whopper for some of these links.

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