<P> Earth 's eccentricity can also play a large role in Earth climate change . The role is perhaps not as large of an impact as Earth 's Obliquity , but still large nonetheless . Eccentricity is defined as the difference in shape between an ellipse and a perfect circle . It is also known by a simpler definition as simply being a measurement of how elliptical something is . In the case of climate , eccentricity is applied to the shape of Earth 's orbit . In a similar fashion to Earth 's obliquity , the more uniform Earth 's orbit is ( more like a perfect circle ) , the less difference there is in climate change throughout the year . Unlike obliquity , eccentricity affects the entire planet approximately the same , instead of primarily changing polar climate . The base idea with eccentricity is this : `` How far away is the earth as a whole from the sun ? '' If there is no eccentricity to Earth 's orbit , then Earth will remain at the same distance from the sun throughout the year , therefore producing no climate change , seeing as how the Earth 's orbit would be perfectly circular around the sun . On the other hand , if Earth 's orbit has a very high eccentricity , Earth would be very close to the sun ( compared to a perfectly circular orbit ) during two opposite seasons , and very far away from the sun during the other two opposite seasons . This effect can be seen by analyzing any ellipse , and observing how flat or how skinny the ellipse becomes as its eccentricity increases . </P>
how would seasons on earth be different if earth 's orbit were less elliptical
less difference there is in climate change throughout the year