SD also looks into the effects that our shiny blue marble's orbit has on the climate on the ground. In short, a lot of things effect the weather and climate.
"Parameters such as planetary gravitational attractions, the Earth's elliptical orbit around the sun and the degree of tilt of our planet's axis with respect to its path around the sun, have implications for climate change and the advent of ice ages."
While the Earth's orbit is elliptical, it is also irregular - meaning that the orbit tends to stretch further from the Sun on occaision, and when that happens, look out -it tends to get a bit chilly. These periods of more elliptical orbits happen about every 100,000 years - the same period of time that separate the more recent Ice Ages.
In addition, the summer and winter months are greatly effected by the Earth's tilt, with the summer months occuring mid year in the Northern hemisphere and at the yearly transistion in the Southern hemisphere. What most people don't realize is that the Earth is actually further away during the middle of the year. However, the Southern summer is greatly mitigated since it is mostly water, which heats five times more slowly than the land which comprises most of the Northern hemisphere. Thus the climatic effects of the seasonal swings is muted, or at least until the situation reverses itself - in 12,000 years. At that point, the seasonal variations will reinforce themselves creating more extreme temperature swings - mcuh warmer in Northern summers and much colder in Southern winters.