If you look at the TOBA YTT site and go to the effect of Volcanic eruptions on Global Temperatures for 600 years, you’ll be able to discern a periodicity of about 76 years in world temperatures. The earth precesses about its axis over tens-of-thousands of years with a nutation (nodding) of about ten degress with a period of 18.6 years. One might note that 18.6 yrs X two (37.4 yrs) is half a nutation cycle, with a full cycle being about 75 years; close to the period of temperature change noted at the Toba site. A nutation would bring different hemispheres of the earth more or less sunlight for periods of 37.4 yrs. The southern hemisphere has relatively more water than the northern hemisphere. And since water has a higher heat capacity than terra firma, it would hold the heat better and transmit it to the oceans and around the Globe. When the Northern hemisphere was heated more, it would heat up faster and cool faster. One half cycle would yeild higher temperatures and the other would be cooler. This appears at first glance to be a better explanation for the minor world temperature increase since the mid 1970′s (when the “Experts” were predicting a coming Ice Age). Taking this cycle into account and that the earth’s temperature changed slightly from cooling to warming in 1976, we can expect the “Experts” to start predicting another Ice Age in 2013.