Every month or so I go on SETI’s "Are We Alone" radio show/podcast with Seth Shostak, and we discuss some weird scientifically distorted news item in a segment we call "Skeptic Check". The latest one is now online, where Seth and I talk about the recent news about the Sun’s potentially weakening magnetic field, and some folks who have leapt to the conclusion that we’re facing a new ice age because of it.
Here’s an article I wrote about this topic, and here’s the direct link to the show. [UPDATE: I just found out the AWA blog has links to the various show segments as stand-alone audio files, so here's the link to mine.]
The conclusion? Spoiler alert: don’t stock up on portable heaters just yet.
Much ado was made over the recent news that the Sun’s magnetic activity may be cooling off over the next few years. Can this mean the Earth itself will literally cool off, slipping into an ice age? Some news sites are reporting it that way (of course, the execrable Daily Mail uses the headline "Earth facing a mini-Ice Age ‘within ten years’ due to rare drop in sunspot activity"; which isn’t even within a glancing blow of reality).
The answer — spoiler alert! — is almost certainly "no". I want to make sure that’s clear, because I will bet essentially any amount of money that some climate change denial sites will run with this story and claim that we don’t need to worry about global warming. That’s baloney, and what follows is why. The reasons take a minute to explain, but of course that’s where the cool stuff (haha!) is. So let’s take this one step at a time. And if you have the attention span of an E. coli bacterium, you can skip down to the conclusion section.
[Note: a lot of this is taken from my book "Death from the Skies!", where I interviewed approximately a bazillion people. One in particular was Caspar Ammann, who was very helpful in explaining the solar connection with the Little Ice Age to me.]
The Quiet Sun
The Sun has a magnetic cycle, its magnetic field waxing and waning in strength roughly every 11 years. The strength and complexity of the solar field governs a lot of the surface activity, including sunspots, solar flares, prominences, and coronal mass ejections.
Right now, in 2011, we’ve just left a period of an extended minimum, and the next max is due in late 2013 and early 2014. But scientists studying the Sun have seen three independent lines of reasoning indicating that the next rise to the solar peak, in 2022 or so, may be delayed or even not occur at all. I wrote about this in an earlier post, so you can get the details there. It’s the core of the "oncoming ice age" claim, so you should read it.
I’ll note right off the bat that not everyone agrees with these findings. Doug Biesecker, a solar physicist NOAA Space Weather Prediction Center [full disclosure: Doug is an acquaintance of mine; I interviewed him for an episode of "Bad Universe" about solar storms] , has written a document calling the findings into question. It’s not exactly a rebuttal; it’s more of a warning not to over-interpret the results. He also points out that a weak cycle may not have an effect on our climate; we simply don’t know for sure.
At this point you may be asking, so what? If the Sun has fewer sunspots and no flares, what difference does that make here on Earth? And how could it possibly trigger an ice age?