Solar Changes and the Climate
By Joseph D’Aleo
The IPCC AR4 discussed at length the varied research on the direct solar irradiance variance and the uncertainties related to indirect solar influences through variance through the solar cycles of ultraviolet and solar wind/geomagnetic activity. They admit that ultraviolet radiation by warming through ozone chemistry and geomagnetic activity through the reduction of cosmic rays and through that low clouds could have an effect on climate but in the end chose to ignore the indirect effect. They stated: “Since TAR, new studies have confirmed and advanced the plausibility of indirect effects involving the modification of the stratosphere by solar UV irradiance variations (and possibly by solar-induced variations in the overlying mesosphere and lower thermosphere), with subsequent dynamical and radiative coupling to the troposphere. Whether solar wind fluctuations (Boberg and Lundstedt, 2002) or solar-induced heliospheric modulation of galactic cosmic rays (Marsh and Svensmark, 2000b) also contribute indirect forcings remains ambiguous.†(2.7.1.3) For the total solar forcing, in the end the AR4 chose to ignore the considerable recent peer review in favor of Wang et al. (2005) who used an untested flux transport model with variable meridional flow hypothesis and reduced the net long term variance of direct solar irradiance since the mini-ice age around 1750 by up to a factor of 7. T
his may ultimately prove to be AR4’s version of the AR3’s “hockey stick†debacle.Earth-sun connectionThe sun is the ultimate source of all the energy on Earth; its rays heat the planet and drive the churning motions of its atmosphere. The amount of energy the sun puts out varies over an 11-year cycle (this cycle also governs the appearance of sunspots on the sun's surface as well as radiation storms that can knock out satellites), but that cycle changes the total amount of energy reaching Earth by only about 0.1 percent (though this unusually weak minimum the drop was 0.15%). A conundrum for meteorologists was explaining whether and how such a small variation could drive major changes in weather patterns on Earth.
Though the sun’s brightness or irradiance changes only slightly with the solar cycles, the indirect effects of enhanced solar activity including warming of the atmosphere in low and mid latitudes by ozone reactions due to increased ultraviolet radiation, in higher latitudes by geomagnetic activity and generally by increased solar radiative forcing due to less clouds caused by cosmic ray reduction may greatly magnify the total solar effect on temperatures. The following is our assessment of the ways the sun MAY influence weather and climate on short and long time scales. The Sun Plays A Role In Our Climate In Direct And Indirect Ways.
http://icecap.us/images/uploads/Solar_Changes_and_the_Climate.pdf
