Physics for Everyone: Maunder Minimum: New Ice Age? (No)
So, a lot of people have been posting articles about the recently released papers on the next big solar minimum, all of them crying that we're going to have an ice age, and to hooey with global warming. Well, I hate to break it to you guys, but we're most likely not going to have an ice age. Pretty much all the paleo evidence we have points to the fact that solar minima, while they can lead to global cooling, do not contribute near as much to global temperatures as another factor that we're suffering badly from right now - heat retention due to carbon compounds in the atmosphere. And boy do we have a lot of them right now.
Currently, we’re at a count of 402.80 carbon dioxide particles per million particles in the air. This is up 1.65 ppm since last year (part of a trend of rising CO2 levels). The recommended sustainable maximum (sustainable for human habitation, that is), is 350 ppm. Since 1960, we have raised our CO2 levels from below 320 ppm to the current levels, an increase of over 82 ppm, or, to put it another way, an increase of over 25%.
To put that in more clear terms, the last time the carbon count was this high, our species did not exist. For most of human existence, the carbon count has been under 300 ppm, until the industrial revolution, when our pollution started to skyrocket the carbon count. Ice ages have generally been associated with very low carbon counts, down to about 180 ppm, which warm periods have all had higher carbon counts, but still lower than what we currently have. In fact, it’s been over a million years since the atmosphere had this much heat-absorbing carbon in it.
And there have been plenty of solar minima, including maunder minima, the kind we’re predicting to happen in the next 15 years. The one back in the 17th Century that froze the Thames? Well, that one didn’t coincide with a high carbon count, but instead a low one that predisposes the planet to colder weather. This one is going to be counter-balanced by a very, very high carbon count.
And why do I think this is going to prevent an ice age, and at most we’ll see a levelling of the average global temperature during the minimum? Because of just what the carbon does. While the solar minimum will reduce the sun’s output briefly, that output will only be slightly lower – our sun is actually a fairly stable star, even with its cycles. While the effect carbon in the atmosphere is, as we see in all paleo evidence (evidence gathered from ice core samples, rock layers, fossil evidence, tree rings, etc), a much bigger factor.
What that carbon does, as I’ve explained in earlier articles, is that it absorbs heat attempting to leave the planet, and then randomly reradiates that heat, resulting in about 50% of the heat that would leave the atmosphere normally being retained, heating us up. It’s like bottling the heat. So even if we receive less heat from the sun, the carbon will retain MORE of that heat balancing, and possibly even overwhelming the cooling effect of the minimum.
Also note that, during the most recent, and famous, Maunder Minimum of the 17th Century when the Thames froze in 1684, that the average Northern Hemisphere Temperature was less than 0.2 degrees Celsius below normal, and the Central England Average Temperature less than 2 degrees Celsius below normal. Further, just two years later, in 1686, England had its fifth warmest winter in a 350 year record. So even not accounting for carbon count, any drop in temperature would actually only barely compensate for the amount we’ve already warmed the globe, and would not be consistent enough to cause an ice age.
So, no, we’re not going to freeze our asses off (except in the more extreme winters that we’re already seeing as a result of global warming), and no, we can’t stop worrying about global warming. In fact, we should worry *more*. Since the Maunder Minima are part of a long-term cycle, and normally would temper out any warming that had occurred before them, this one won’t. This may affect any long-lived species that have evolved to withstand (and possibly even flourish during) minima, and will keep our global average temperature too *warm* during the period of the minimum, hurting species we rely on for our survival. While human beings are indeed a very resilient and adaptable species, most of our food sources are not near as adaptable as we are. And that is about what we need to be concerned.