June 20th, 2011
Econintersect: An interesting climatological tug of war may be developing. Sunspots have a well established effect on the earth's climate and global temperatures. Sunspot activity appears to be headed into a period of abnormally low activity which, if it continues to develop, would have a depressing effect on global temperatures. This would be occurring at a time when the increase in the so-called greenhouse gases are projected by many scientists to be pushing global temperatures higher. Follow up:
Follow up:The sun normally follows an 11-year cycle of activity. The current cycle, Cycle 24, is now supposed to be ramping up towards maximum strength. Increased numbers of sunspots and other indications ought to be happening but they are occurring at a much reduced level compared to expectations. Scientists at the NSO (National Solar Observatory) now suspect that the current Cycle 24 may be very weak and Cycle 25 may not happen at all.
At this point in the sunspot cycle relatively accurate projections can be made about sunspot activity over the next 5-10 years. The following graph from NASA shows the projections:
The predicted size would make this the smallest sunspot cycle in over 100 years, according to NASA. The following NASA graphs show the cycles over the past several centuries:
The last time the sunspot cycle peaks were at the low levels projected for the coming decade were between 1800 and 1825. In the graph below (Wikipedia) a dip in the various estimates for temperature of the earth is clearly evident right after 1800.
An even more pronounced dip in temperature estimates occurred in the 1600s. This was a period that saw a period of sunspot activity called "The Maunder Minimum" and corresponded to a climate period known as "The Little Ice Age." From NASA:
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 (see graph below). 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. The connection between solar activity and terrestrial climate is an area of on-going research.
Scientists are not sure whether a repeat on the Maunder Minimum is at all likely, but a repeat of something like the early part of the 1800s is certainly possible based on the current data.
This will lead to the possibility of some interesting science to experimentally determine the relative importance of the impact of sunspots and greenhouse gases on the climate of the planet.
Hat tip to Naked Capitalism.