Obliquity, What's That?

Is it earth's obliquity or eccentricity cycles that are predominant causes of global warming? Obliquity, another anomaly of the earth's axis, ranges from 22.1 to 24.5 degrees. Right now we're at about 23.5 degrees. Our elliptical orbit changes from more circular to oval. With an oval configuration, temperature difference between the two positions of perihelion and aphelion can be 20-30 percent. The concern is what happens when these two cycles coincide, with the most perihelion and the most extreme tilt. Extremes of hot and cold, right? Now add crossing the galactic equator, which happens only every 30 million years. We're passing the outer edge right now. The part I like best is the eclipse of the galactic center by the solstice sun in 2012. The Mayans had over 20 different calendars, all synchronized. They knew all this about 3000 years before we did.