I’ve been skeptical about the whole global warming issue, and I’d like to be equally skeptical about a new ice age threat:
What may be the science story of the century is breaking this evening, as heavyweight US solar physicists announce that the Sun appears to be headed into a lengthy spell of low activity, which could mean that the Earth — far from facing a global warming problem — is actually headed into a mini Ice Age.
Lower sunspot activity translates into likely lower temperatures here on earth, just like in the “Maunder Minimum” period, also known as the “Little Ice Age”.
Early records of sunspots indicate that the Sun went through a period of inactivity in the late 17th century. Very few sunspots were seen on the Sun from about 1645 to 1715. Although the observations were not as extensive as in later years, the Sun was in fact well observed during this time and this lack of sunspots is well documented. This period of solar inactivity also corresponds to a climatic period called the “Little Ice Age” when rivers that are normally ice-free froze and snow fields remained year-round at lower altitudes. There is evidence that the Sun has had similar periods of inactivity in the more distant past.
As I wrote back in 2004, “I’ve never been all that convinced of the accuracy of the scientific evidence presented in favour of the Global Warming theory, especially as it seemed to play rather too clearly into the hands of the anti-growth, anti-capitalist, pro-world government folks. A world-wide ecological disaster, clearly caused by human action, would allow a lot of authoritarian changes which would radically reduce individual freedom and increase the degree of social control exercised by governments over the actions and movement of their citizenry. “
On the other hand, as Bjorn Lomborg has pointed out, humanity is better adapted to dealing with higher temperatures than lower ones — as are most living creatures. Given a choice between the risks of increasing temperatures globally and the risks of a new ice age, it should be pretty easy to figure out which scenario allows the better chances for all of humanity to survive and thrive.
Update: Anthony Watts has more. “If we are right, this could be the last solar maximum we’ll see for a few decades,” Hill said. “That would affect everything from space exploration to Earth’s climate.”
Update, 15 June: My skepticism is overwhelmed by the skeptic-in-this-instance New Scientist‘s Michael Marshall, who does the quick math that a Maunder Minimum for the next 90 years would only lower global temperatures by 0.3C. And New Scientist is still bullish on the global warming potential of between 2 and 4.5 degrees Celsius over that same time period. They’re science writers and I’m not, but I have to say I’m still much more worried about the potential cooling than the potential warming.
You should remember, though, that the current level of warming is noticeably more than half composed of the upswing to the current maximum from the previous mid-century low (some calculations say almost 100%) – so a drop of “only” 0.3 degrees C would basically erase AGW and completely invalidate the whole theory. Sure, you can get AGW fans to claim that solar variability had nothing to do with the warmth, but those claims are pretty much erased by this week’s news.
When you look at the solar activity charts, the one striking thing you see is that they match up REALLY well to Earth’s surface temperature. Note that it’s solar cycle length that makes the difference, not amplitude. And yes, that includes the last 50 years or so.
Comment by cirby — June 15, 2011 @ 17:53