Here’s the nice thing about the sun-spot theory: It’s a testable hypothesis. We should be able to confirm or disprove the sun-spot hypothesis within a few years.
I have frequently expressed skepticism of dire Global Warming scenarios by noting that the increase in global temperatures over the past 20 years fits the lowest range of forecasts made by the climate models. Sorry, folks, I just can’t get exercised about warming-generated calamities, no matter how many after-the-fact justifications are proffered to explain the failure of reality to conform with theory.
On the other side, the anti-Global Warming crowd has advanced an alternative explanation for climate change. The extreme skeptics suggest that solar activity — sun spots, or the lack of them — have a far greater influence on earth’s climate than the level of CO2 in the atmosphere. According to this theory, solar radiation interacts with the earth’s magnetosphere to block cosmic radiation from penetrating to the atmosphere and seeding cloud formation. Boiling the argument down to its essence, more sun spots predict higher temperatures on earth, fewer sun spots predict lower temperatures. We may have reached put-up-or-shut-up time for that theory as well.
The skeptics are getting excited now because the incidence of sun spots is crashing. Indeed, sun spots have almost disappeared. The last time the sun exhibited similar characteristics was in the 1600s, the so-called Maunder Minimum which coincided with a decline in global temperatures known to history as the Little Ice Age. If the solar warming rejectionists are correct, “global warming” could disappear in a hurry.
Writes Robert Zimmerman with the Global Warming Policy Forum:
If the solar minimum has actually arrived now, this would make this cycle only ten years long, one of the shortest solar cycles on record. More important, it is a weak cycle. In the past, all short cycles were active cycles. This is the first time we have seen a short and weak cycle since scientists began tracking the solar cycle in the 1700s, following the last grand minimum in the 1600s when there were almost no sunspots.
If the planet is entering a new solar minimum, the theory would predict falling temperatures. Perhaps not immediately — there may be buffering effects that aren’t well understood — but in not too many years.
Here’s the nice thing about the sun-spot theory: It’s a testable hypothesis. The theory states in no-uncertain terms that solar radiation as measured by sun spots is a key driver of earth’s climate. The theory says that cycles in earth’s temperatures closely match cycles in sun spot activity. We appear to be entering a phase in which sun spots are going dormant. Temperatures should drop — not just for a year or two but in a sustained matter. We should be able to confirm or disprove the sun-spot hypothesis within a few years.
If the sun-spot hypothesis is confirmed by the data and we see a decisive shift in temperature trends, the theory that posits CO2 as the driving climate variable will be dashed. Conversely, if the sun-spot model is proven incorrect, a lot of moderate Global Warming skeptics (like me) will be more receptive to the CO2 model — although it still has to explain the two-decade-long pause. (“Pause” is not quite the right word. Global temperatures have crept higher. They just haven’t conformed to predictions.)
Perhaps I’m being naive to think that reality will settle the debate. Reality has a way of being frustratingly complex and ambiguous, and zealots are endlessly creative at devising fallback theories. We didn’t account for the effect of increased particulates in the atmosphere. Or temperatures didn’t rise as expected because the missing heat is lurking undetected deep in the ocean.